Harken 7411.11 User Manual

MKIV UNDERDECK JIB REEFING & FURLING

Unit 1, 2, 3

Installation Manual – Intended for specialized personnel or expert users

Preassembly

Parts 4–5
Rigging Parts Check/Tools 6
Dimensions/Sailmaker's Instructions 7
Stay Length Deductions/Stay Into Foil Options 8

Hub Assembly

Deck Flange 9
Install Hub Assembly in Bow 10–11
Assemble Drum Components 11
Underdeck Lead Block 12

Preassembly

Top Foil Length (Unit 1) 13
Top Foil Length (Unit 2) 14
Top Foil Length (Unit 3) 15
Short Top Foil (Unit 1) 16
Short Top Foil (Unit 2) 17
Short Top Foil (Unit 3) 18
Confirm Foil Length 19

Assembly

Foils/Connectors 20–26
Halyard Swivel 26
Torque Tube Assembly 27
Rod Rigging 28
Attach Turnbuckle/Foils to Boat 29–31
Feeder/Final 32

Commissioning

Turnbuckle 33–34
Lead Line to Cockpit 35
Halyard Swivel Height/Angle 36
Halyard Restrainer/Tension 37

Operation

Halyard/Headstay Tension 38
Raise Sails/Storm Sails/Reefing 39–40
Secure Sail 40
Race Conversion 41

Maintenance

Clean/Lubricate/Inspect 42
Confirm Deck Flange/Tack Swivel Gap 42
Replace Line 42
Storage/Transporting 42
Remove Furler 42

Troubleshooting/Warranty

4656 01/14

Please read these instructions carefully before installing, servicing, or operating the equipment.

This manual may be modified without notice. See: www.harken.com/manuals for updated versions.

PLEASE SAVE THESE INSTRUCTIONS

Parts Description

Introduction

This manual gives technical information on installation and service. This information is destined exclusively for
specialized personnel or expert users. Installation, disassembling, and reassembling by personnel who are not
experts may cause serious damage to property or injury to users and those in the vicinity of the product. If you
do not understand an instruction contact Harken.

The user must have appropriate training in order to use this product.
Harken accepts no responsibility for damage or harm caused by not observing the safety requirements and

instructions in this manual. See limited warranty, general warnings, and instructions in www.harken.com/manuals.

Purpose

®

Harken

Jib Reefing and Furling is designed for rolling sails on sailboats to reduce sail size or to completely roll
so wind has little effect on the sail. Use of this product for other than normal sailboat applications is not covered
by the limited warranty.

Safety Precautions

WARNING! This symbol alerts you to potential hazards that may kill or hurt you and others
if you don't follow instructions. The message will tell you how to reduce the
chance of injury.

18

CAUTION! This symbol alerts you to potential hazards that may hurt you and others if
you do not follow instructions. The message will tell you how to reduce the
chance of injury.

WARNING! Strictly follow all instructions to avoid potential
hazards that may kill or hurt you and others. See www.harken.com/
manuals, for general warnings and instructions.

14

6

7

5

4

2

1

3

Parts Descriptions

1) Lower Jaw/Jaw Toggle

2) Threaded Stud

3) Length Adjuster Nut

4) Hub Assembly

2 MKIV Underdeck Unit 1, 2, 3

11

9

8

5) Flange Assembly

6) Guard Assembly

7) Cover Assembly

8) Deck Flange

13

12

WARNING! Do not drill boat's chainplate or toggle.
This may result in rig failure. Use the correct
size toggle and clevis pin.

10

2. Harken does not recommend drilling boat’s chainplate or toggle.
Bushings may be available to fit boats with smaller clevis pin sizes.

Part No. Size Wire Size Rod Size Clevis Pin Ø

7411.11

7412.11 5/

7413.11

7413.11

1

/

2

Unit 1

8

Unit 2

3

/

4

Unit 3

7

/

8

Unit 3

1

/4", 9/32", 5/16"

6 mm, 7 mm, 8 mm

5

/16", 3/8"

8 mm, 10 mm

7

/16", 1/2"

11 mm, 12 mm

7

/16", 1/2"

11 mm, 12 mm

15

Size Check

1. Check headstay and clevis pin
dimensions in chart below.

-8, -10

5.72 mm 6.35 mm

-12, -17

14 mm, 8.38 mm

-22, -30

9.53 mm, 11.1 mm

-22, -30

9.53 mm, 11.1 mm

9) Tack Swivel

10) Tack Shackle

11) Bearing Caps

12) Upper Jaw/Jaw Toggle

12.7 mm

15.9 mm

19.1 mm

22.2 mm

5

3

7

½"

/8"

/4"

/8"

16

Standard

Headstay Length

45' 11"

13.99 m
60' 4"

18.38 m
75' 1"

22.88 m
75' 1"

22.88 m

13) Torque Tube Universal

14) Torque Tube Assembly

15) Foil Clamp

16) Bottom Foil

19

17

Max.

Headstay Length

52' 11"

16.12 m
67' 4"

20.51 m
82' 1"

25.02 m
82' 1"

25.02 m

Preassembly Sizing Check

25

19

20

21

22

23

A B

24

26

E

D

F

C

Will Drum Fit in Bow?

H

Note: If length of stud does not allow attachment to chainplate, link plates

G

between chainplate and toggle must be fabricated.

Furler Requires Drained Compartment

Harken’s Underdeck Furler is designed to keep much of the water from

I

entering the bow compartment. Water will drip through the furler during
rain or when sailing in heavy weather. Furling compartment must drain.

Unit Part No. A B C D Max E F G Min G Max H Min H Max I J

1

2

3

3

7411.11

7412.11

7413.11

7413.11

1

/

2

51/2"

140 mm

5

/

8

65/8"

167 mm

3

/

4

83/16"

208 mm

7

/

8

83/16"

208 mm

49/16"

116 mm

51/16"

129 mm

61/2"

166 mm

61/2"

166 mm

411/16"

119 mm

51/4"

134 mm

3

6

/4"

172 mm

63/4"

172 mm

11/2"

38 mm

113/16"

46 mm

21/2"

64 mm

21/2"

64 mm

11

/

16

3

94 mm

3

/

16

"

4

106.5 mm

7

/

16

"

5

138.5 mm

7

/

16

"

5

138.5 mm

5

2

"

/16"

58 mm

3

2

/4"

70 mm

5

3

/8"

92 mm

5

3

/8"

92 mm

45/8"

117 mm

53/8"

137 mm

67/8"

175 mm

75/16"

186 mm

95/8"

244 mm

115/16"

287 mm

143/8"

365 mm

15"

381 mm

105/8"

270 mm

1211/16"

322 mm

161/8"

410 mm

169/16"

421 mm

J

155/8"

397 mm

189/16"

471 mm

5

23

/8"

600 mm

241/4"

616 mm

1

/2"

12.7 mm

5

/8"

15.9 mm

3

/4"

19.1 mm

7

/8"

22.2 m

41/8"

105 mm

5"

127 mm

65/16"

160 mm

65/16"

160 mm

17) Feeder

18) Connector Bushing

19) Bottom Connector

MKIV Underdeck Unit 1, 2, 3 3

20) 7' (2.13 m) Foil

21) Connector Screws

22) Connector Wedge

23) Connector

24) Halyard Swivel

25) Trim Cap Screws

26) Trim Cap

Preassembly Parts

Halyard Swivel

Cover Assembly

Flange Assembly

7' (2.13 m)

Foils

2' (610 mm)

Bottom Foil

Guard Assembly

Torque Tube

Assembly

Hub Assembly

Main Components

Part No.

Description Unit 1 Unit 2 Unit 3-3/4 Unit 3-7/8 Qty

Halyard swivel H-39812 H-39794 H-39392 H-39392 1

Torque Tube Assembly HFG927 HFG928 HFG929 HFG929 1

Hub Assembly HFG923 HFG924 HFG925 HFG926 1

Cover Assembly HFG683 HFG686 HFG689 HFG689 Pair

Flange Assembly HFG684 HFG687 HFG690 HFG690 Pair

Guard Assembly HFG685 HFG688 HFG691 HFG691 Pair

4 MKIV Underdeck Unit 1, 2, 3

Line (Not included with Furler)

Note: Line is not included with furler. Drum of
unit is smaller to allow it to fit into narrow bow
sections. If overlapping sails are used, standard
diameter line will fill up drum and jam furler. To
prevent this, use small diameter, high strength
line at forward end and have a rigger add a
cover at aft end where line is handled.

Line Specifications

Unit Forward Ø

1

1

/4" (6 mm) 2500 lb (1130 kg)

5

2

/16" (8 mm) 3740 lb (1700 kg)

3

3

/8" (10 mm) 5000 lb (2270 kg)

Foils (Standard Package)

Description Unit Part No. Qty

7' (2.13 m) Foil

2' (610 mm) Bottom foil 7411.33 1

7' (2.13 m) Foil

2' (610 mm) Bottom foil 7412.33 1

7' (2.13 m) Foil

2' (610 mm) Bottom foil 7413.33 1

Min Break

Strength Aft Ø

5

/16" (8 mm)

3

/8" (10 mm)

7

/16" (12 mm)

7411.30 6

1

7412.30 8

2

7413.30 10

3

Preassembly Parts

Connector Bushings

Trim Cap Screws

Bottom

Connectors

Connector

Hex Keys (Supplied)

Description Unit Qty

2.5, 4, 5 mm 1 1 Each

3, 4, 5, 6 mm 2 1 Each

3, 4, 6, 10 mm 3 1 Each

Other Components

Unit 1 Unit 2 Unit 3 (3/4, 7/8)

Description Part No. Qty Size Part No. Qty Size Part No. Qty Size

Connector

Bottom connector

Bow shackle

7411.31 5 7" (177.8 mm) 7412.31 7

7411.32 1 10.75" (273 mm) 7412.32 1

2110 3 6 mm 2117 3

Plastic

Connector

Wedges

Prefeeder

Bow Shackles

Hex Keys

Blue Loctite

Foil Screws

®

Red Loctite

9" (229 mm)

13" (330 mm)

8 mm

Feeder

®

7413.31

7413.32

2124

Trim Cap

Injector

Adhesive

9 9.75"(248 mm)

1 14" (356 mm)

3 10 mm

5200

Unit 1 Unit 2 Unit 3 (3/4, 7/8)

Description Part No. Qty Part No. Qty Part No. Qty

Connector bushing set

Plastic connector wedge set

Foil screw set

Trim cap set

Trim cap screw set

Prefeeder

Feeder with screw and tab

Injector, 1 oz. 5200 Adhesive

®

Loctite

Blue

®

Loctite

Red

MKIV Underdeck Unit 1, 2, 3 5

HFG295

(12-H-42062/12-H-42063)

HFG299

(14-H-39625)

HFG343

(28-HFS1105)

HFG680

(H-37361/H-37362)

HFG629

(3-HFS1126)

947

H-39683

HFG725

833

HFG739

1

1

1

1

1

1

1

1

1

2

HFG296

(16-H-42032/16-H-42033)

HFG300

(18-H-39487)

HFG348

(36-HFS1106)

HFG681

(H-37403/H-37404)

HFG672

(3-HFS1127)

947

H-39559

HFG725

833

HFG739

1

(20-H-42073/20-H-42074)

1

1

1

1

1

1

1

1

2

HFG297

HFG324

(22-H-39487)

HFG349

(44-HFS1106)

HFG682

(H-39751/H-39752)

HFG672

(3-HFS1127)

947

H-39756

HFG725

833

HFG739

1

1

1

1

1

1

1

1

1

2

Preassembly Rigging Parts Check/Tools

1. Stud/eye turnbuckle components are not included and
must be purchased separately. See page 8.

2. Rod rigging requires Harken rod adapter stud.

3. Order Harken Lead Blocks and one additional
7403 if necessary. Fits 1" (25 mm) stanchions.

Unit 1, 2

7404 Lead Block Kit

(Sold Separately)

131, 047

349, 2652

Recommended Furling
Compartment Lead Blocks

Unit Turning Thru-Deck

1 349 131

2 2652 047

3 2600/137/071 HC7981

Tools You Will Need

ROD RIGGING

Harken Rod Adapter

Stud Required

(Sold Separately)

Rod Adapter Stud

Unit Part No. Thread Ø

7422 -8

1

7423 -10

7424 -12

2

7425 -17

7426 -22

3

7427 -30

1

/2" - 20RH

1

/2" - 20RH

5

/8" - 18RH

5

/8" - 18RH

3

/4" - 16RH

7

/8" - 14RH

Adhesive Alert

MKIV Furlers are shipped with 3M 5200
adhesive. Use adhesives on dry connectors
and foils using the special injection system
described in the assembly section. Parts
may immediately be exposed to rain. Cure
is best at 70F (22C) with 50% humidity. Do
not apply at temperatures below 40F (5C)
and above 100F (38C).

Although adhesive has not cured it will
remain in place on foil joints whether
they are left on the ground or raised up
on boat. Foils can be raised immediately
after assembly and sails fitted.

Note: A small amount of adhesive may
bulge out of injection ports. If possible
let system sit for a couple days before
sailing. If adhesive gets on sails remove
using acetone. For faster-curing adhesive,
purchase 4200 Fast Cure.

Note: Damaged foils can be repaired.
Use a hand-held propane torch to heat
joints until foils can be pulled apart.

Unit

5

16

3

1

8

Unit Drill Ø

1
2

3 (3/4, 7/8)

4

12

5
5

1

/32"
/32"

/8"

(3 mm)

(4 mm)
(4 mm)

, 1/4"

, 1/4"
, 1/4"

(6.25 mm)

(6.25 mm)
(6.25 mm)

15

Unit

18

2

Deck

Flange Ø

1 3.7"

(94 mm)

2 4.2"

(106.5 mm)

3 5.45"

(138.5 mm)

Wrench Size

for Length Adjuster

1

2 1"

3 1.25"

7

(22 mm)

(25 mm)

(32 mm)

Saw Size

(95 mm)

(110 mm)

(140 mm)

/8"

19

6

10

13

Use 6 mm bolts and washers to
mount deck flange. To figure bolt
length, add 3/8" (10 mm) to deck
thickness. Minimum thread

7

9

11

14

1. Long tape measure 6. Side cutters 11. Center punch 16. Hole saw

2. Short tape measure 7. Rat-tail file 12. Rigging or black tape 17. Deck sealant

3. Power drill 8. Hex Keys (provided) 13. Scissors 18. Box end wrench

4. Drill bits (see chart) 9. Slotted/phillips screwdrivers 14. Metal straight edge 19. 6 mm bolts, nuts and washers

5. Hacksaw 10. Needle-nose pliers 15. Hammer

6 MKIV Underdeck Unit 1, 2, 3

17

engagement must be 9mm.

Hole

3 ¾"

4 ¼"

5 ½"

Preassembly Dimensions/Sailmaker's Instructions

Luff Length

Note offsets above and below sail.
A shorter luff may be required if a halyard restrainer is necessary

(page 37) or a toggle or long toggle assembly is used to raise drum.
If luff of sail is not long enough to put halyard swivel near top of

headstay foil, a pendant must be added. See page 36.

A

B

Tack Setback

Find setback "C" for tack shackle in chart below and modify sail
accordingly. Setback is measured to luff tape of sail.

Luff Tape Size

6

All units require #6 (

/32" or 5 mm) luff tape.

Luff Tape Length

Cut off top of luff tape so it is 18 to 24" (450 to 600 mm) below
head of sail. This allows head to lag behind rest of sail to help
flatten sail. It will also help head to roll more smoothly.

Note feeder height and extend bottom of luff tape downward so
it is below feeder. This will prevent luff tape from catching in
feeder as sail is lowered.

Tack and Head Shackles

F

Make sure tack and head shackles fit sail
rings. The minimum inside dimensions
of standard head and tack shackles are:

A

Unit A B

1

1

/16" (27 mm)1/2" (13 mm)

1

3

2

/4" (44 mm)

1

7

3

/8" (48 mm)

C

1

11

/16" (17 mm)

13

/16" (21 mm)

B

Suncover

Suncovers may be installed on either side of sail. Be

E

D

G

Unit Part No. A B C D E F G

1 7411.11 1/

2 7412.11

3 7413.11

3 7413.11

sure to match other sails in the customer's inventory.

43/4"

2

120 mm

55/8"

5

/

8

143 mm

75/16"

3

/

4

186 mm

75/16"

7

/

8

186 mm

7"

177 mm

91/8"

231 mm

115/8"

296 mm

115/8"

296 mm

115/16"

49 mm

25/16"

59 mm

33/16"

81 mm

33/16"

81 mm

1

/16"

2 mm

1

/16"

2 mm

1

/16"

2 mm

1

/16"

2 mm

—

9

/16"

14mm

7

/16"

11mm

—

13

/16"

37

960 mm

411/16"

1043 mm

473/16"

1199 mm

1

/16"

46

1170 mm

35/8"

92 mm

41/16"

104 mm

53/8"

136 mm

513/16"

148 mm

MKIV Underdeck Unit 1, 2, 3 7

Preassembly Deduction for Stay Length/Stay Into Foil Options

Use dimensions of Harken toggle below to build stay to correct length.

Tip: Turnbuckles should be 1/2 to 2/3rds open to allow shortening for new wire stretch and for fine-tuning mast rake.

A

B

C

D

Unit Part No. A B C D

1 7411.11

2 7412.11

3 7413.11

3 7413.11

1

/

2

5

/

8

3

/

4

7

/

8

1

/16"

2 mm

1

/16"

2 mm

1

/16"

2 mm

1

/16"

2 mm

5

3

/8"

92 mm

1

4

/8"

104 mm

53/8"

136 mm

513/16"

148 mm

105/8"

270 mm

1211/16"

322 mm

1

16

/8"

410 mm

169/16"

421 mm

155/8"

397 mm

189/16"

471 mm

235/8"

600 mm

241/4"

616 mm

Options for Snaking Stay into Foils

1. Swage stud at end of wire.

2. Open end of wire and install Norseman or Sta-Lok

®

stud after

foil is assembled.

3. Rod adapter nosepiece for Harken rod adapter stud: Threaded
nosepiece must have a positive lock as well as adhesive.
Use Harken stud with cotter pins. See page 28.

WARNING! Using a threaded nosepiece with only
adhesive at the upper rod eye terminal may result
in headstay system failure. Make sure there is a
mechanical lock.

8 MKIV Underdeck Unit 1, 2, 3

Assembly Deck Flange

1

/2°

–

74

1

/2°

72

Note: Deck flange angle
matches a stay angle of

1

/2° when compared

73
to deck. Angles can vary

1

between 72

/2° and 741/2°.

Carefully locate center point in deck to
locate deck flange. Line from mast to
under deck chainplate must intersect this
center point. Mark center fore/aft and
athwartships line. Use template to mark
four outer holes and center pilot hole.
Make sure closer pair of holes is forward.

Once you are certain hole is located in
line with chainplate and any required
shimming is done, drill hole 90° to deck.

Make sure hole is just large enough so deck
flange bears against deck. It is better to
make hole slightly smaller and file opening
larger to fit. Use template to mark large hole
and bolt holes. Use hole saw to drill deck.

Tip: After pilot drill bit clears deck, drill final
hole from bottom using pilot hole to line up
hole drilled from top. This will prevent glass
from chipping.

If deck does not fall within these angles,
shims must be made using structural
adhesive to avoid excessive pressure
on deck and deck bearings.

Use 6 mm screws and compound to fasten
deck flange.

3

Note: There must be a minimum of

/8"

(9 mm) thread engagement into deck flange.

MKIV Underdeck Unit 1, 2, 3 9

Assembly Install Hub Assembly in Bow

Slide hub assembly into deck
flange. Turn adjusting nut to
lengthen or shorten threaded
stud as needed.

Stud Length Turn Adjusting Nut

Shorten Clockwise

Lengthen Counter-Clockwise

Adjust length so toggle is lined up with chainplate hole. Slide pin
into chainplate and secure with cotter pin.

1

1

/16"–

/8"

2–4 mm

Distance between bottom of
tack swivel and deck flange

1

must be

/16"–1/8" (2–4 mm).

From on-deck, pull up on unit to check height between deck flange and
tack swivel. Make sure tack swivel is free to rotate when there is upward
pressure on unit. Check this again when stay is up and tensioned.

10 MKIV Underdeck Unit 1, 2, 3

Assembly Assemble Drum Components

Place halves of plastic flange in
lower groove on hub assembly
so smooth side of flange is up.

Tip: Line up flats in flange with
flats in groove.

Place halves of plastic cover in
grooves so flats in cover align
with flats in groove.

Tip: Rotate each screw hole
towards the stern.

Use blue Loctite

®

screws (provided).

Use blue Loctite

®

screws (provided).

on flathead

on flathead

Tighten screws using hex key
(provided).

Tighten screws using hex key
(provided).

Assemble line guard so enclosed
opening faces lead block. Do not

®

use Loctite

on threads.

Tip: Loosely thread both screws
turning guard so it can be rotated
to its final position. Finish
tightening final screw when
enclosed opening faces lead
block.

MKIV Underdeck Unit 1, 2, 3 11

Assembly Underdeck Lead Block

Mount lead block so that line exits furler
at 90° to line of headstay as shown.
Remember block will split angle and raise
up slightly under load. Mount thru-deck
block. You may want to angle it toward
stanchion block.

90°

Mount thru-deck block. You may want to
angle it toward stanchion lead block.

12 MKIV Underdeck Unit 1, 2, 3

UNIT 1

Preassembly Unit 1—Top Foil Length

Measure A and add to this chart
and length chart below

Inches mm

A

B .50 13

E 24 610

F 15.25 387

Total A+B+E+F

Make sure upper
measurement points
of A and pin-to-pin

Alternate

Measurement

Point

A

are the same.

TOP FOIL LENGTH WORKSHEET

1

2

3

4

To find “D” pick number from chart below that is clos­est to, but not greater than total from step 3.

5

Result (Pin-to-Pin – ABEF)

Inches mm

3 x 84 = 252
4 x 84 = 336
5 x 84 = 420
6 x 84 = 504
7 x 84 = 588
8 x 84 = 672

Example–If result from Step 3 is:

500 inches “D” = 420 inches 12,000 mm

Result (C) Top Foil Length

Pin-to-Pin Length

Subtract ABEF

Subtract D

3 x 2133.6 = 6400.8
4 x 2133.6 = 8534.4
5 x 2133.6 = 10668
6 x 2133.6 = 12801.6
7 x 2133.6 = 14935.2
8 x 2133.6 = 17068.8

“D” = 10,668 mm

–

–

Pin

to

Pin

A

B

C

D

Pin

to

Pin

Length Check

After completing worksheet above fill in A, C and D below. Add “A”
through “F” to confirm total equals your pin-to-pin measurement.

A Center of Pin to Bottom of Terminal
B Bottom of Terminal to Top of Foil
C Top Foil Length

D Number of Foils ________ x 84" (2133.6 mm)

E Bottom Foil 24 610
F Bottom of Foil to Jaw/Jaw Toggle 15.25 387

Length Chart

Dimensions Inches mm

.50

Pin-to-Pin Length

13

E

F

MKIV Underdeck Unit 1 13

UNIT 2

Preassembly Unit 2—Top Foil Length

Measure A and add to this chart
and length chart below

Inches mm

A

B .63 16

E 24 610

F 18.45 469

Total A+B+E+F

Make sure upper
measurement points
of A and pin-to-pin

Alternate

Measurement

Point

A

are the same.

TOP FOIL LENGTH WORKSHEET

1

2

3

4

To find “D” pick number from chart below that is clos­est to, but not greater than total from step 3.

5

Result (Pin-to-Pin – ABEF)

Inches mm

5 x 84 = 420
6 x 84 = 504
7 x 84 = 588
8 x 84 = 672
9 x 84 = 756

Example–If result from Step 3 is:

500 inches “D” = 420 inches 12,000 mm

Result (C) Top Foil Length

Pin-to-Pin Length

Subtract ABEF

Subtract D

5 x 2133.6 = 10668
6 x 2133.6 = 12801.6
7 x 2133.6 = 14935.2
8 x 2133.6 = 17068.8
9 x 2133.6 = 19202.4

“D” = 10,668 mm

–

–

Pin

to

Pin

A

B

C

D

Pin

to

Pin

Length Check

After completing worksheet above fill in A, C and D below. Add “A”
through “F” to confirm total equals your pin-to-pin measurement.

A Center of Pin to Bottom of Terminal
B Bottom of Terminal to Top of Foil
C Top Foil Length

D Number of Foils ________ x 84" (2133.6 mm)

E Bottom Foil 24 610
F Bottom of Foil to Jaw/Jaw Toggle 18.45 469

Length Chart

Dimensions Inches mm

.63

Pin-to-Pin Length

16

E

F

14 MKIV Underdeck Unit 2

UNIT 3

(

3/4, 7/8

)

Preassembly Unit 3—Top Foil Length

Measure A and add to this chart
and length chart below

Inches mm

A

B 1 25

E 24 610

F 23.4 594

Total A+B+E+F

Make sure upper
measurement points
of A and pin-to-pin
are the same.

Alternate

Measurement

Point

A

TOP FOIL LENGTH WORKSHEET

1

2

3

4

To find “D” pick number from chart below that is clos­est to, but not greater than total from step 3.

5

Result (Pin-to-Pin – ABEF)

Inches mm

7 x 84 = 588
8 x 84 = 672
9 x 84 = 756

10 x 84 = 840
11 x 84 = 924

Example–If result from Step 3 is:

800 inches “D” = 756 inches 20,000 mm

Result (C) Top Foil Length

Pin-to-Pin Length

Subtract ABEF

Subtract D

7 x 2133.6 = 14935.2
8 x 2133.6 = 17068.8
9 x 2133.6 = 19202.4
10 x 2133.6 = 21336

11 x 2133.6 = 23470

“D” = 19,202 mm

–

–

Pin

to

Pin

A

B

C

D

Pin

to

Pin

Length Check

After completing worksheet above fill in A, C and D below. Add “A”
through “F” to confirm total equals your pin-to-pin measurement.

A Center of Pin to Bottom of Terminal
B Bottom of Terminal to Top of Foil
C Top Foil Length

D Number of Foils ________ x 84" (2133.6 mm)

E Bottom Foil 24 610
F Unit 3-
F Unit 3-

3

/4–Bottom of Foil to Jaw/Jaw Toggle 24 610

7

/8–Bottom of Foil to Jaw/Jaw Toggle 23.4 594

Length Chart

Dimensions Inches mm

1

Pin-to-Pin Length

25

E

F

MKIV Underdeck Unit 3 15

Preassembly Unit 1—Short Top Foil

UNIT 1

If top foil is shorter than 7" (177.8 mm), use one of the following special techniques to ensure sufficient bearing
surface for the foil in the area of the halyard swivel.

" (38 mm)

/2 (64 mm)

7" (178 mm)

/2

1

1

2" (51 mm)

2

1" (25 mm)

1

Cut-Offs

Do Not Use

7" (178 mm) No special treatment required.

21/2"–1" (64–25 mm) Shorten top foil and adjoining

full length foil so two screws are used to assemble joint
instead of four. Do not use plastic bushings above top
connector.

6"–5" (150–130 mm)

Cut-Offs

Do Not Use

6"–5" (152–130 mm) Do not use plastic bushing above

top connector.

/2"–4" (115–100 mm)

1

4

41/2"–4" (115–102 mm) Do not use plastic bushing

above top connector. Shorten top of connector and if
necessary shorten trim cap.

Cut-Offs

Do Not Use

Top Foil

Length from

Worksheet

1

2

/2"

(64 mm)

2"

(51 mm)

1

/2"

1

38 mm)

1"

(25 mm)

1. Initial
top foil
cut length

57/8"

(149 mm)

5

(137 mm)

47/8"

(124 mm)

4

(111 mm)

3

/8"

3

/8"

2. Cut through
middle hole in
top foil.*

Resulting Top

Foil Length Length

41/8"

(105 mm)

35/8"

(92 mm)

31/8"

(79 mm)

25/8"

(67 mm)

3. Shorten
full length
adjoining
foil by
cutting
through
middle
hole.*

4. Shorten
connector

(89 mm)

(89 mm)

(89 mm)

(83 mm)

5. Shorten
trim cap

31/2"

31/2"

31/2"

31/4"

*To allow for saw cut, position blade so upper half of
middle hole is preserved.

No

No

Yes

Yes

/2" - 3" (90 - 75 mm)

1

3

Cut-Offs – Do Not Use

31/2"–3" (90–75 mm) Do not use plastic bushing above

top connector. Cut connector right at cross formed by
glue dispersion channels. Use single foil screw in top
foil only.

16 MKIV Underdeck Unit 1

Under 1" (25 mm)

Under 1" (25 mm) Eliminate top foil and run foil higher

in torque tube.

Preassembly Unit 2—Short Top Foil

UNIT 2

If top foil is shorter than 8

11

/16" (221 mm), use one of the following special techniques to ensure sufficient

bearing surface for the foil in the area of the halyard swivel.

/16" (221 mm)

11

8

811/16" (221 mm) No special treatment required.

/8" (219–162 mm)

3

/8"–6

5

8

Cut-Offs

Do Not Use

85/8" – 63/8" (219–162 mm) Do not use plastic bushing

above top connector.

2" (64 mm)

2" (38 mm)

/

1

3" (76 mm)

/

1

2" (51 mm)

2

1" (25 mm)

1

Cut-Offs

Do Not Use

3"–1" (76–25 mm) Shorten top foil and adjoining full

length foil so two screws are used to assemble joint
instead of four. Do not use plastic bushings above top
connector.

Top Foil

Length from

Worksheet

3"

(76 mm)

1

/2"

2

(64 mm)

2"

(51 mm)

1

/2"

1

(38 mm)

1"

(25 mm)

1. Initial
top foil
cut length

7

(184 mm)

63/4"

(172 mm)

6

(159 mm)

53/4"

(146 mm)

5

(133 mm)

1

/4"

1

/4"

1

/4"

2. Cut through
middle hole in
top foil.*

Resulting Top

Foil Length Length

51/8"

(130 mm)

45/8"

(117 mm)

41/8"

(105 mm)

35/8"

(92 mm)

31/8"

(79 mm)

3. Shorten
full length
adjoining
foil by
cutting
through
middle
hole.*

4. Shorten
connector

(114 mm)

(114 mm)

(114 mm)

(95 mm)

(95 mm)

41/2"

41/2"

41/2"

33/4"

33/4"

5. Shorten
trim cap

No

No

No

Yes

Yes

/2" (152–140 mm)

1

6"–5

Cut-Offs

Do Not Use

Cut-Off

Do Not Use

6"–51/2" (152–140 mm) Do not use plastic bushing

above top connector. Shorten top of connector and if
necessary shorten trim cap.

*To allow for saw cut, position blade so upper half of
middle hole is preserved.

/8" (133–92 mm)

5

Cut-Offs – Do Not Use

/4"–3

1

5

Under 1" (25 mm)

51/4"–35/8" (133–92 mm) Do not use plastic bushing

above top connector. Cut connector right at cross formed
by glue dispersion channels. Use single foil screw in top
foil only.

MKIV Underdeck Unit 2 17

Under 1" (25 mm) Eliminate top foil and run foil higher
in torque tube.

Preassembly Unit 3—Short Top Foil

UNIT 3

If top foil is shorter than 9

3

/4" (248 mm), use one of the following special techniques to ensure sufficient bearing

surface for the foil in the area of the halyard swivel.

/4" (248 mm)

3

9

93/4" (248 mm) No special treatment required.

/8" (244–181 mm)

1

/8"–7

5

9

Cut-Offs

Do Not Use

95/8"–71/8" (244–181 mm) Do not use plastic bushing

above top connector.

2" (89 mm)

2" (64 mm)

/

1

2

2" (38 mm)

/

1

2" (51 mm)

1

/

1

3" (76 mm)

3

Cut-Offs

Do Not Use

31/2"–11/2" (89–38 mm) Shorten top foil and adjoining

full length foil so two screws are used to assemble joint
instead of four. Do not use plastic bushings above top
connector.

Top Foil

Length from

Worksheet

1

3

/2"

(89 mm)

3"

(76 mm)

1

/2"

2

(64 mm)

2"

(51 mm)

1

/2"

1

(38 mm)

1. Initial
top foil
cut length

69/16"

(167 mm)

6

(154 mm)

69/16"

(167 mm)

5

(129 mm)

49/16"

(116 mm)

1

1

/16"

/16"

2. Cut through
middle hole in
top foil.*

Resulting Top

Foil Length Length

5"

(127 mm)

41/2"

(114 mm)

4"

(102 mm)

31/2"

(89 mm)

3"

(76 mm)

3. Shorten
full length
adjoining
foil by
cutting
through
middle
hole.*

4. Shorten
connector

(124 mm)

(124 mm)

(124 mm)

(111 mm)

(95 mm)

47/8"

47/8"

47/8"

43/8"

33/4"

5. Shorten
trim cap

No

No

No

Yes

Yes

/2" (178–140 mm)

1

7"–5

Cut-Offs

Do Not Use

7"–51/2" (178–140 mm) Do not use plastic bushing

above top connector. Shorten top of connector and if
necessary shorten trim cap.

/8"–4" (137–102 mm)

3

5

Cut-Offs – Do Not Use

53/8"–4" (137–102 mm) Do not use plastic bushing

above top connector. Cut connector right at cross formed
by glue dispersion channels. Use single foil screw in top
foil only.

18 MKIV Underdeck Unit 3

Cut-Off

Do Not Use

*To allow for saw cut, position blade so upper half of

middle hole is preserved.

2" (38 mm)

/

1

Under 1

Under 11/2" (38 mm) Eliminate top foil and run foil

higher in torque tube.

Preassembly Confirm Foil Length

Confirm foil length by laying foils along­side stay with turnbuckle components
and torque tube assembly. Pull stay out
straight. Line up turnbuckle eye with a
point just above bottom of torque tube
assembly. This point will line up with

Unit Pin

1

1

/2" (12.7 mm)

5

2

/8"(15,9 mm)

3

3

/4" (19.1 mm)

7

3

/8"(22.2 mm) 1" (25 mm)

Jaw/Jaw Toggle Pin to Bottom of

Torque Tube Assembly

7

/16" (11 mm)

1

/4" (6 mm)

5

/8"(16 mm)

Jaw/Jaw toggle pin. See chart above right.

Line up bottom foil so foil clamp is just
above or below center of notches in
bottom foil.

Note: Position top foil so that with top
cap the foil will ride 5/8" (16 mm) below
terminal. If wire fitting at top of stay is
swage, foil must ride just below shoulder
of swage. Mark cut line on foil. Wrap tape
around foil as a guide so cut is straight.

MKIV Underdeck Unit 1, 2, 3 19

Assembly Top Foil

Cut foil to length using hacksaw.

Deburr inside edge using rat-tail file.

Prepare top foil for drilling.

Tip: Mark top foil to distinguish
from cutoff piece.

Scribe line on top of foil to mark drill
holes. Lay top foil alongside cutoff
piece and use a flat metal object
(i.e. metal ruler) to scribe top
line of foil.

20 MKIV Underdeck Unit 1, 2, 3

Assembly Top Foil

Cut out template at right. Line template up
with top of foil and scribed line. Tape in
place. Use a center punch to mark holes.

Check center punch marks to confirm
they from top of foil (see chart below).

Unit Center Punch Marks

1
2

3 (3/4, 7/8)

3

/16" (5 mm) 1" (25 mm)

3

/8" (10 mm) 1

3

/8" (10 mm) 1

3

/16" (30 mm)

3

/8" (35 mm)

!

Foil

3

/16" (5 mm)

Top

Unit 1

1" (25 mm)

Drill two (2) holes for trim cap. See chart
below for correct drill size

Unit Drill Ø

1 1/8" (3 mm)
2 5/32" (4 mm)

3 (3/4, 7/8) 5/32" (4 mm)

!

Foil

3

Top

/8" (10 mm)

Unit 2

13/16" (30 mm)

!

Foil

3

Top

Unit 3 (3/4, 7/8)

/8" (10 mm)

13/8" (35 mm)

Lay top foil in line with others. Slide stay
into top foil and down line of foils or slide
each foil up stay.

MKIV Underdeck Unit 1, 2, 3 21

Assembly Top Foil

Install trim cap. Place each side over wire.

Push trim cap into foil to start, then tap
in using hammer.

Install trim cap screws.

Place halves of plastic bushings on stay so
hooked part of longer section faces out.

Tip: With foil screw holes up as shown
below, place longer half of bushing
with hook on upper half.

22 MKIV Underdeck Unit 1, 2, 3

Assembly Top Foil/Connectors

Slip connector on wire, mating hook of
plastic bushing with connector.

Put a drop of red Loctite® into screw holes.

MKIV Underdeck Unit 1, 2, 3 23

Assembly Foils/Connectors

Hold plastic wedge in place with thumb
as you insert into foil. Line foil holes
with connector screw holes.

Loading Injector with Adhesive

Tip: In cooler weather, keep sealed
adhesive in pocket to keep warm. Use
instructions below to fill injector less
than half way; you will only use a small
amount of adhesive. Refill if needed
but do not keep open sealant for long
periods. Use adhesive within 3 hours.

Use cap of adhesive to break seal. Remove
injector tip cap and plunger. Hold injector
at an angle with applicator tip facing down.
Squeeze adhesive into tube so lower half
of injector is full as shown. Keep tip free
of sealant to let air inside.

Adhesive in
lower half

Start plunger into injector and immediately
hold upright so plunger is down and
applicator tip is up.

As sealant runs down towards plunger an
air pocket will form near tip. Push plunger
to evacuate air. You are now ready to begin
injecting adhesive.

24 MKIV Underdeck Unit 1, 2, 3

Assembly Foils/Connectors

Inject only a small amount of adhesive
into middle hole. See chart below for
amount.

Tip: When you see a small amount of
adhesive enter one of the screw holes,
stop. You have applied enough adhesive.

Unit Adhesive (ml)

1
2

3 (3/4, 7/8) 1 – 1

1

/3 – 1/

3

/4 – 1

2

1

/

4

Stop when you see a small
amount of adhesive enter
one of the screw holes.

Use “ml”

marks to
estimate
adhesive

Tighten screws into connector holes. Make

®

sure a drop of red Loctite

entered each

screw hole. If not, apply to screw.

Red Loctite

®

Use bushings, connector, wedge and
adhesive in other screw hole and
insert into other foil. Use adhesive (see
chart below for amount).

Unit Adhesive (ml)

1
2

3 (3/4, 7/8) 1 – 1

MKIV Underdeck Unit 1, 2, 3 25

1

/3 – 1/

3

/4 – 1

2

1

/

4

Assembly Bottom Foil/Connectors/Halyard Swivel

Continue installing connectors and wedges.

®

Make sure to use red Loctite

in screw

holes.

Red Loctite

®

Continue assembly. Use bottom connector
to assemble bottom foil.

Slide halyard swivel onto foil above feeder
window. Make sure taller “half” is up as
shown.

26 MKIV Underdeck Unit 1, 2, 3

Assembly Torque Tube Assembly

Loosen foil clamp screws at top of
drum assembly.

Slide drum assembly onto foils.

Tip: Face clamp downward so it
clears foil notches during installation.

Temporarily clamp torque tube assembly
to top of bottom foil, leaving feeder gap
partially exposed as shown at right. Gap
will be used to rig a foil system lifting line.

MKIV Underdeck Unit 1, 2, 3 27

Assembly Rod Rigging: Rod Adapter Stud

Apply a few drops of red

®

Loctite
nosepiece.

Screw main threaded stud
portion onto bronze nosepiece
until flats align with two cotter
pin holes in terminal body.

Tip: Turn nosepiece completely
into threaded stud portion.
Flats will be close and may
only require a small half turn
to align with cotter pin holes.

to threads of

Insert two cotter pins and

®

spread. Clean excess Loctite
from terminal body using
special care to ensure that
there is no red Loctite
threaded stud.

®

on

ROD RIGGING

28 MKIV Underdeck Unit 1, 2, 3

Assembly Attach Turnbuckle/Foil System to Boat

Thread turnbuckle and threaded eye to stud
protruding from foil. Assemble
turnbuckle.

Note: If using Sta-Lok

®

or Norseman

®

stud, you must use a washer above
stud as shown below.

Washer

Taking care not to lose parts, remove bearing caps from
drum assembly.

Tip: Rig a large round plastic wash basin below furler
to catch any parts that may be lost overboard.

MKIV Underdeck Unit 1, 2, 3 29

Assembly Attach Turnbuckle/Foil System to Boat

Carefully Raise foil and stay up onto boat.
Raise foils using line attached to feeder
gap as shown.

Attach eye to jaw/jaw toggle deck level
using clevis pin. Adjust turnbuckle.
Secure with cotter pin.

Secure with cotter pin.

Adjust turnbuckle.
When stay length is set,

use side cutters or needle­nose pliers to bend cotter pin to secure turnbuckle.

30 MKIV Underdeck Unit 1, 2, 3

Assembly Attach Turnbuckle/Foil System to Boat

Check to make sure there is a 1/16"–1/8"
(2–4 mm) gap between the deck flange and
tack swivel. If necessary loosen adjusting
nut below and take up on turnbuckle to
increase gap between deck flange and
tack swivel when turnbuckle is tightened.

Check to make sure
there is a 1/16" –1/8"
(2–4mm) gap

Loosen foil clamp while holding torque tube assembly
and carefully lower into place.

Note: Do not remove screws, just loosen them.

Check foil height at top, set and
secure using hex key.

See tip on next page.

Capture posts on universal posts with caps and

®

secure with screws. Do not use Loctite

on screws.

Tip: If it is hard to capture posts in cap, push against
stay to help align universal. If necessary loosen
backstay.

MKIV Underdeck Unit 1, 2, 3 31

Assembly Feeder/Final

Tip: Do not remove foil clamp screws to adjust foil.
Loosen screws, hold foils and bring clamp away
from foils. Adjust and reclamp.

Slide halyard swivel above feeder. Place feeder in foil
recess. Push screw down so tab catches under foil.

Tighten screw.
Note: Screw will turn with some difficulty. It is plastic

coated to prevent loosening due to vibration.

Important! When removing feeder, loosen screw no more
than one full turn. Slide screw up and remove feeder.

32 MKIV Underdeck Unit 1, 2, 3

Commissioning Turnbuckle on Boat

Have extra cotter pins on hand to replace used ones
at base of unit and for turnbuckle.

Hold foils and loosen torque tube screws until you
can pull clamp part way out in order to lower foils.

Lower foils.
Rig a screw catcher. Remove screws holding bearing

caps and remove taking care to not lose parts.

Loosen, but do

not remove

MKIV Underdeck Unit 1, 2, 3 33

Commissioning Turnbuckle on Boat

Slide torque tube assembly onto foil and clamp just
below top of feeder gap as shown. Use halyard to lift
foil assembly.

CAUTION! Foils can drop suddenly causing injury
to hands. Make sure drum assembly and foils are
securely lifted using a halyard before adjusting
turnbuckle.

Check to make sure there is a 1/16"–1/8" (2–4 mm)
gap between deck flange and tack swivel. If necessary
loosen adjusting nut below and take up on turnbuckle to
increase gap between deck flange and tack swivel when
the turnbuckle is tightened.

Reassemble Torque Tube Assembly to Hub Assembly.

®

Do not use Loctite

on screws.

Tip: If it is hard to capture posts in cap, push against
stay to help align universal. If necessary loosen
backstay.

Lift foils so top is 1/2"–3/8" (12 mm–16 mm) below
upper terminal.

Slide foil clamp into foil notches and tighten screws
to secure.

Adjust turnbuckle

Check to make sure
there is a 1/16" - 1/8"
(2 - 4mm) gap

34 MKIV Underdeck Unit 1, 2, 3

Commissioning Lead Line to Cockpit

Run line through enclosed window in guard and into
hole in bottom plate of spool. Tie a small overhand
knot and pull it up under drum assembly.

WARNING! Lead line through enclosed
window. If line is led through opening
between two enclosed windows it can ride
above lineguard and jam furler which can

Enclosed Window

cause loss of control of boat.

Note location of sun cover. Charge system by rotating furler to wrap line on drum.

Tip: Sun cover to starboard—turn clockwise to charge. Sun cover to port—turn counter-clockwise.
Tension line while charging.

Mount Lead Blocks

Furling line can be led down either side of boat. If boat is in slip, consider mounting opposite dock.
Remove four screws on stanchion blocks. Clamp blocks to stanchions. See instructions below.

Tip: Start all four screws before tightening.

BOW

7401 Forward Lead Block

349 – Unit 1, 2
2652 – Unit 3

088 – Unit 1, 2
131 – Unit 3

7401

FORWARD

LEAD

BLOCK

7403

OUTBOARD

STANCHION

BLOCK

7403

OUTBOARD

STANCHION

BLOCK

Position Forward Lead Block so line enters drum
at right angles to headstay and centers vertically

90°

in opening. Install so line is inside stanchion.

Correct block position is critical to even
line spooling and ease of furling.

7403 Outboard Stanchion Blocks

Install 7403 Outboard Stanchion Blocks so line is
outside stanchions.

Number and placement of leads depends on boat
length and number/configuration of stanchions.

7402 Ratchet Stanchion Block

Mount 7402 Ratchet Stanchion Block as furthest-aft
lead to prevent line overrides in drum when unfurling.
Position ratchet block so line turns at least 90°.

Install so line is inside stanchion.

Lead line through block so ratchet makes
clicking sound when pulling line to furl sail.

Tip: Make sure ratchet switch is in “ON” position. If there is
no clicking sound, lead line through block in opposite direction.

Lead line to Furling Line Cleat in cockpit.

HCP168 Furling Line Cleat

Install so line is angled as shown.
Use #10 (5 mm) fasteners.

7402

RATCHET

STANCHION

BLOCK

STERN

MKIV Underdeck Unit 1, 2, 3 35

Note: As furling line lead changes, make sure line
doesn’t chafe against line guard. Rotate line guard
if necessary.

Drum Full

(sail unfurled)

Drum Empty

(sail furled)

Commissioning Halyard: Swivel Height/Lead Angle

Halyard Wrap

The most serious problem with furling systems occurs when the jib halyard
wraps around the headstay foil. Halyard wraps will keep you from furling or
unfurling and may cause serious damage to the unit and the halyard.

WARNING! In severe cases, a halyard wrap can cause loss
of control of boat and/or headstay can break suddenly. Make
sure halyard is clear of top foil before using system.

If Halyard Wraps

If halyard wraps, do not force unit to turn. Attempt to open sail by carefully
furling in and out a little at a time. If sail will unfurl, lower it by releasing jib
halyard. Severe halyard wraps can only be cleared by a professional going
aloft and freeing halyard.

If sail will not furl or unfurl, try to remove jib sheets and manually wrap
sail around headstay.

WARNING! Do not go aloft on boat’s halyards if there has been a halyard wrap. Do not use boat. Damage
to halyard, headstay, stay terminals, or connections as a result of a halyard wrap may cause these parts to
break suddenly causing mast to fall down while person is aloft. Sailing or motoring with boat after a wrap
can result in the headstay breaking and mast falling down. Before using boat, have a professional rigger
inspect and replace parts as necessary using following methods.

A professional rigger must carefully inspect the masthead area using a secure hoisting method. Inform rigger that
there has been a halyard wrap so they can avoid an accident by relying on standing rigging or halyards. Inspection
must be done while rigger is suspended from a separate crane or mast must be lowered to perform inspection. Some
professionals may rig a new line through internal masthead sheaves to serve as a temporary headstay to hold mast in
place. Wire, rod rigging, terminals, toggles, clevis pins, or cotter pins must be inspected and replaced if they show any
signs of damage.

Prevent Halyard Wrap

To prevent wraps, the halyard must exert a slight pull to the rear. This
allows the foils to turn while halyard remains stationary.

WARNING! Sail must be fitted to foil length before using
to prevent halyard wraps and possible headstay loss.

1. Halyard swivel should be within top 4–6" (100–152 mm) of foil unless
a halyard restrainer is used.

8–10°

2. Halyard must pull slightly to rear (8–10°).

3. Halyard must be snug, but not too tight.

Test furler at dock, but if water is smooth an incorrect lead angle may not
be apparent. Halyard wraps usually occur in wave action when lead angle
is not correct. The 8–10° angle shown at right is critical.

36 MKIV Underdeck Unit 1, 2, 3

Commissioning Halyard: Restrainer/Tension

Pendants

If the your sail luff is not long enough to position halyard swivel high
enough to create an 8–10° angle as shown, you must add a pendant.
Pendants should be made of plastic-coated wire and be permanently
attached so sail height will be correct. Adjustable- length pendants
are not acceptable, as they might not be adjusted correctly during
a sail change.

1. Raise sail, but do not attach tack shackle.

2. Position halyard swivel correctly near top of headstay.

3. Secure halyard.

4. Tie a piece of rope to sail tack.

5. Lead line through tack shackle on furling drum.

6. Tension sail.

7. Measure distance from tack shackle to sail tack and permanently
attach pendant of this length to head of sail.

8. Repeat procedure for every jib in your sail inventory.

Halyard Deflector/Halyard Restrainer

To prevent wraps, jib halyard must pull slightly to rear. On most boats,
halyard lead angle is acceptable if halyard swivel is raised to top of foil.

On some boats halyard sheaves are located too close to headstay and
a Halyard Deflector or Halyard Restrainer must be used.

Halyard restrainers should be used only when required by masthead
geometry. Restrainers tend to limit sail luff length and may cause
problems if not installed properly.

If your boat needs a Halyard Deflector, use Part No. 7302 or a Halyard
Restrainer, use Harken Part No. 944.

Restrainer should be mounted as high as possible on face of mast.
Position restrainer so that foils will not hit it when under load.

The restrainer should deflect halyard as little as possible or you may
experience difficulty in tensioning sail luff, friction when furling, and
possible damage to foils. To decrease deflection angles, shorten sail luff.

Halyard Deflector

Tip: Boats used in charter service should have a halyard restrainer,
regardless of masthead geometry.

Halyard Tension

The jib halyard should be firm, but not too tight.

Tip: The luff foil system supports sail along its length so halyard
tension is used only to shape sails, not to support them. Use enough
halyard tension to remove some wrinkles along luff of sail. Do not
tension halyard enough to cause vertical wrinkles in luff of sail.
Tension to adjust position of draft in sail to suit sailing conditions.
Halyard should be firm but not tight. If in doubt, release halyard
tension. To protect sail, ease halyard when boat is not in use.

Halyard Restrainer

MKIV Underdeck Unit 1, 2, 3 37

Operation Halyards/Headstay Tension

Spinnaker Halyards

Spinnaker halyards occasionally cause problems
with furling.

WARNING! In severe cases, spinnaker halyards
can jam furler causing loss of control of boat
which can cause an accident, damage to your
vessel, personal injury or death. See www.
harken.com/manuals for additional safety
information.

On many boats it will not be possible to attach spinnaker
halyard to bow pulpit or it may be "sucked" into jib when
furling.

On some boats the spinnaker halyard lays across
headstay and will catch on halyard swivel, foils or
jib halyard. To prevent problems it may be necessary
to install a masthead bail to move spinnaker halyard
block forward and to one side.

Boats with external halyards may find it necessary to
flip both ends of spinnaker halyard behind spreaders
to prevent fouling with furling system.

Headstay Tension

A furling system will work best if headstay is tight.
A loose headstay is difficult to rotate and can cause

unusual wear on foil joints.
To adjust headstay tension, remove sail and furling line

from unit and follow instructions on page 30.

Tip: Before adjusting headstay tension, slack
mainsheet and vang.

Backstay Adjusters

Backstay adjusters allow headstay tension to be varied to change sail shape to match
conditions. They permit a very tight headstay to be eased when boat is not in use.
For best performance, consider adding a backstay adjuster; either a block and tackle,
a mechanical adjuster like those offered by Harken, or a hydraulic adjuster.

Remember to keep headstay tight for best performance when furling or reefing.
If your boat is fitted with an adjuster be sure that it is tensioned before the

halyard is tensioned. If not, backstay adjuster may increase halyard tension
and could damage the sail or furling system.

Racing boats often slack the headstay completely when sailing downwind.
Check to be sure that foil does not jam against upper headstay terminal when
backstay is released. To prevent this, it may be necessary to shorten foil slightly.

38 MKIV Underdeck Unit 1, 2, 3

Operation Raise Sail/Storm Sail/Reef

Raise Sails

1) Install prefeeder by securely tying end of line to a deck fitting or to
toggle below furler so it is 2' (610 mm) below feeder.

2) Shackle tack of sail to tack shackle. Install shackle so screw pin head
is on same side as sun cover.

3) Secure genoa sheets to clew of sail.

4) Attach genoa halyard to halyard swivel.

5) Pass luff tape through prefeeder and feeder into foil groove.

6) Attach head of sail or pendant at head of sail to halyard swivel.

7) Hoist sail.

Tip: New sails are often stiff and may hang up on prefeeder during
raising. Do not force sail when it hangs up—lower and remove
twist. Sails "break in" with use and will become easier to raise.

Storm Sails

Most people will use one multipurpose genoa for all their sailing, but it is not good seamanship to go offshore
without storm sails.

Heavy-air working jibs and storm sails may be used with your unit. These sails need to have luff tape added to
allow them to be raised in headstay foils.

These sails will generally require pendants to ensure that halyard swivel is properly positioned at top of headstay.
See page 36.

Remember that heavy-air working jibs and storm jibs may be reefed and furled like any other sail.

Furl and Reef

To furl or reef, ease the jib sheets and pull
furling line.

In very light air, it may be necessary to place
some tension on jib sheet to insure a tight furl.

In a breeze, you must completely luff sail by
totally slacking jib sheets before furling.

The furling line should pull readily. The amount
of force required is related to amount of wind,
but Unit should never require use of a winch
to furl. If the sail will not furl, or if furling
requires a great deal of effort, there is a problem with system. Consult the Troubleshooting Guide on page 43.
Do not use a winch to force a system to turn. If you are certain that the system is operating properly, you may
use a winch to make furling easier.

MKIV Underdeck Unit 1, 2, 3 39

Operation Reef/Secure Sail

Reef

A sail may be partially furled before you resume
sailing. This is known as reefing.

Many sailors find it helpful to place marks on
foot of sail so that they can reef to a variety of
predetermined jib sizes. This allows marks to be
placed on jib lead tracks or toe rail so that lead
block position can be changed to correspond
to reefed jib.

Sails are generally reefed to balance boat and to
reduce heeling moment. Sails may also be reefed
to improve visibility or to slow boat while sailing
in congested areas or entering or leaving harbors.

Secure Sail

When furling the sail completely, make sure sheets and furling line are
secured. Check amount of line on the spool compared to the furled sail
before using the system.

A furled sail must have:

a. Two to three wraps of jib sheet wrapped around sail.
b. Two wraps minimum of line wound on spool.
c. Furling line securely cleated.

d. Jib sheets securely wrapped on winch and held in self-tailing jaws.
Furl at dock with tension on sheets to duplicate furling in high wind.
Remember sails furled in light wind and left loosely secured can be a

problem if wind increases.

IMPORTANT! Remove sail from furler if extreme winds are predicted,
especially if boat is left unattended.

IMPORTANT! Check all points above—a, b, c, and d—when leaving
boat to avoid damage to furler or boat.

A loosely rolled sail can catch wind in a storm. Sheets or furling lines can
loosen as winds increase and allow furler to unroll. If no wraps of line are
on spool, the line deadend can break the drum when the boat motors
through waves.

Be sure mooring lines are not placed across furling line where they may
cause chafe.

a. 2–3 wraps

b. 2–3 wraps

If you want to:
Add more wraps of
jibsheet on furled sail.
Add more wraps of line
on spool.

40 MKIV Underdeck Unit 1, 2, 3

Untie jib sheets and keep sail
completely rolled. Secure with
sail tie.

Turn spool to unroll a
couple of wraps of line.

Turn spool to add a
couple of wraps of line.

Retie sheets.

Operation Race Conversion

Race conversion allows use of both
grooves for sail changes and tacking
genoas on deck for use of maximum
luff length genoas.

Halyard Swivel Below Feeder

Use halyard to lift halyard swivel up, away
from feeder. Loosen screw one revolution
only. Slide screw up and hold. Remove
feeder carefully—bottom end first. Don’t
lose the feeder overboard! Lower swivel
onto torque tube. Replace feeder.

Halyard Swivel Off Furler

Serious racers may want to remove the
halyard swivel.

1) Remove drum assembly.

2) Rig a secure, temporary headstay.

3) Loosen backstay, mainsheet and vang
so that headstay goes slack.

4) See procedure on pages 29 - 31.
Note: It is not possible to remove halyard

swivel on a unit with a Norseman/Sta-Lok

®

or rod adapter stud unless you disassemble
terminal stud. Make sure you use a new

®

Norseman/Sta-Lok
Norseman/Sta-Lok

wedge to reassemble

®

fitting.

Remove Feeder

Loosen screw one revolution only. Slide screw up and hold.

To Remove
Feeder For

Racing

1.

2.

1. Loosen screw
one revolution only.

2. Slide screw up.
Remove feeder.

3. Lower halyard
swivel.

Carefully remove feeder–bottom
end first. Don't drop the feeder

overboard!

MKIV Underdeck Unit 1, 2, 3 41

Maintenance Clean/Inspect/Remove Furler

Clean and Lubricate

Keep unit clean. When you wash boat, flush unit with
soap and fresh water. Occasionally lower sail and
flush halyard swivel with soap and fresh water.

At least twice a year unit should be cleaned more
thoroughly by removing line (first note direction of
spool) and flushing bearings with soap and fresh
water. After unit has dried, apply a dry spray lubricant

®

such as McLube

.

Foils may be cleaned by washing with soap and water.
A scrap of luff tape may be run up foil to scrub inside

WARNING! Periodically inspect items listed
below and any others as necessary. Failure
to inspect can cause an accident.

Inspect

grooves. If lubrication is required, spray a thin coat of

®

McLube

SailKote on sail luff tapes away from boat deck.

WARNING! Do not spray foil on boat. McLube
will cause slippery decks which may result in
loss of footing, falling overboard.

Inspect unit for signs of chafe, wear, or damage.
Inspect locking devices below drum and inside torque tube

for signs of loosening. Check headstay tension for signs of
loosening.

Inspect swage fitting and lower toggle for signs of stress
corrosion.

®

Inspect Norseman or Sta-Lok

terminal or rod terminal for

signs of loosening.
Inspect all screws on unit to be sure they have not loosened.
Inspect foil to make sure that it has not dropped into torque

tube. Periodically inspect wire for signs of wear or unraveling.

Confirm Gap Between Deck Flange and Tack Swivel

Check to make sure there is a 1/16"–1/8" (2–4 mm) gap
between the deck flange and tack swivel. If necessary
loosen adjusting nut below and take up on turnbuckle

Check to
make sure
there is

1

/16"–1/8"

a
(2 - 4mm)
gap

to increase gap between deck flange and tack swivel
when turnbuckle is tightened.

Storage – Mast Down

In areas where it freezes, do not store system where water
can accumulate in foils. When water freezes it will rupture
aluminum. Store foils under cover, with grooves facing down or on an angle so water will run out.

Storage/Transporting

Do not store or transport system with drum assembly extending beyond mast. Remove masthead clevis pin and
shift furler up so drum assembly can be strapped securely to mast. Some people remove drum assembly and
halyard swivel for storage and transport.

After Storage or Transport

After storing or transporting unit, clean thoroughly including ball bearings. See instructions above.

Remove Furler From Boat

In order to prevent foils from locking against upper stay terminal when backstay is released, loosen torque tube screws
and lower foil before loosening backstay.

42 MKIV Underdeck Unit 1, 2, 3

®

Troubleshoot

Problem Probable Cause Solution

Sail will not furl or
is difficult to furl.

Jib halyard is wrapping around headstay because
angle between mast and and halyard is too shallow

Jib halyard is wrapping around the headstay
because halyard swivel is too low.

Jib halyard is too tight. Ease jib halyard.
Foils riding on turnbuckle. Raise foils. See adjusting turnbuckle on page 34.
Foils too high, binding on swage eye. Lower foils until clear. See adjusting turnbuckle on page 34.
Spare halyard is wrapping in sail as it furls. Secure spare halyards away from furling headstay by flipping them behind spreaders
Salt or dirt in bearings. Flush bearings frequently with fresh water and a detergent solution.
Furling line tangled in drum. Overrides are best prevented by using a 7402 ratchet block as the last furling line lead to

Stop knot catching. Make sure knot is a single overhand and is pushed up inside drum.
Sail full of wind. Luff completely before furling or reefing.
Sail flogging too much. Release a short length of sheet, pull some furling line and repeat.
Jib sheets are not free. Free jib sheets.
Foil out of torque tube. Reinstall foil in torque tube and tighten clamp screws.
No wraps of furling line on drum. Remove sheets. Rotate stay wrapping as much furling line on drum as possible.
Lineguard assembly has slipped down. Tighten line guard assembly screws securely.
Line through 7402 ratchet backwards. Rerun line.
Halyard swivel installed upside down. Remount swivel correctly.

Sail will not unfurl
or will not unfurl
completely.

Jib halyard is wrapping around headstay because
angle between mast and halyard is too shallow.

Jib halyard is wrapping around the headstay
because the halyard swivel is too low.

Foils riding on turnbuckle. Raise foils. See adjusting turnbuckle on page 34.
Foils too high, binding on swage eye. Lower foils. See adjusting turnbuckle on page 34.
Jib halyard is too tight. Ease jib halyard.
Spare halyard is wrapping in sail as it furls. Secure spare halyards away from furling headstay by flipping them behind spreaders
Salt or dirt in bearings. Flush bearings with freshwater and lubricate with dry spray lubricant such as McLube
Furling line is not free. Free furling line.

Sail will not furl
completely.

Insufficient furling line on drum. Remove sheets. Rotate stay, wrapping as much furling line on drum as possible.
Too much line on drum. Adjust amount of line on drum or change position of forward lead block to allow line

Spare halyard catching in sail as it furls. Move halyards away from furling headsail as above.

Headstay rotates in

Insufficient tension on headstay. Tighten headstay and/or backstay to eliminate sag in headstay.

jerks or elliptically.

Sail does not stay
furled.

Sail will not go up.

Sail not furled tightly on stay. Maintain drag on sheets while furling.
Furling line not secure. Secure furling line.
Luff tape will not go into groove. Check luff tape for fraying.

Sail catching at prefeeder. Flake sail more loosely on deck.
Dirt in groove. Clean groove.

Sail will not raise
completely or luff
will not tension.

Sail will not

Halyard swivel is hitting end stop. Luff of sail is too long and must be recut.
Angle between halyard and mast is too sharp

and halyard is pulling too much to the rear.
Halyard is wrapping on headstay. Angle between headstay and halyard is too shallow and must be optimized per installation

come down.

Halyard swivel off foil. Sail luff too long or foil is too short or low and must be lengthened or raised.

Ultravoilet cover rolls

Furling line is wrapped on drum in wrong direction. Remove sheets. Pull line to remove all furling line from drum. Turn stay to rewind line on

up inside of sail.

Line jams between

Line is not led through windows. Pull line through enclosed window.

guard and plastic
spool plate.

Delrin® is a registered trademark of E. I. du Pont de Nemours and Company or its affiliates.
Igus® is a legally registered trademark of Igus® GmbH and/or Igus® Inc.
Loctite® is a trademark of Henkel AG & Company KGaA

See installation instructions regarding optimal halyard angle. It may be necessary
to mount a halyard restrainer on front of your mast to hold halyard to rear.

See installation instructions regarding optimal halyard swivel height. A wire pendant
may be needed at head of sail to raise halyard swivel to proper height.

maintain proper drag on line while unfurling.

See installation instructions regarding optimal halyard angle. It may be necessary to
mount a halyard restrainer on front of your mast to hold halyard to rear.

See installation instructions regarding optimal halyard angle.

to roll evenly on drum.

Check luff tape size.

Halyard must be routed from a point higher on mast. This may require that any halyard
turning blocks aloft be replaced or sail shortened.

instructions.

drum in opposite direction. Line guard and cowling alignment may need to be adjusted.

McLube™ is a registered trademark of McGee Industries, Inc.

®

is a registered trademark of Sta-Lok Terminals, Ltd.

Sta-Lok

®

is a registered trademark of Solvay Advanced Polymers

Torlon

®

Online Product Registration

www.harken.com/FurlingWarranty

MKIV Underdeck Unit 1, 2, 3 43

Warranty: www.harken.com/manuals

or call, write, email, or fax Harken, Inc.,

Pewaukee, WI USA

MKIV Underdeck Unit 1 Parts List

HFG684 HFG683HFG685

HFS980

H-38817

HFS980

H-38818

H-38293

HFS1052

1 2

1

2

No. Description Order Part No.

Top Cover Assembly w/Screws 1 HFG683

1

2

3

4

Top Cover 2 H-38817
Top Cover Screw (M4 x .7 x 10MM) 2 HFS980

Bottom Flange Assembly w/Screws 1 HFG684

Flange 2 H-38818
Bottom Flange Screw (M4 x .7 x 10MM) 2 HFS980

Guard Assembly 1 HFG685

Guard Set 2 H-38293
Guard Screw (M6 x 1 x 40MM SHCS) 2 HFS1052

No. Description Order Part No.

Torque Tube Assembly 1 HFG927

1 Clamp 1 H-42954
2 Clamp Screw (M5 x .08 x 12MM SHCS) 4 HFS827

Hub Assembly 1 HFG923

1 Cotter Pin (
2 Clevis Pin (
3 Bearing Cap w/Insert 2 HFG931

A Bearing Cap 1 AL-8101
B IGUS

4 Socket Head Cap Screws (M5 x .8 x 10MM) 4 HFS334

Ball Plug 5 H-35144A
Torlon
Delrin

5 Deck Flange 1 H-42461

5

/32" x 1.250") 4 HFS203

1

/2" x 1.146") 4 H-42395

®

Bushing 1 H-43838

®

Ball Bearing (5/16") 28 MP-129

®

Ball Bearing (5/16") 134 MP-118

MP-129
H-35144A

4

H-35144A
MP-118
H-35144A
MP-118
H-35144A

MP-118

H-35144A
MP-118

3

HFG927

1

2

3

3

B

A

B

A

4

HFG923

Pin Measurements

*Grip

Length

*Pin measurements

are "Grip Length."

1

2

1

2

5

44 MKIV Underdeck Unit 1

4

3

2

1

7424 -12

3

7424 -17

7422 -8
7423 -10

5

5

No. Description Order Part No.

Rod Adapter Stud (-8) w/Nosepiece 1 7422 -8

1 Stud (Main Body) 1 H-41536
2 Nosepiece (-8) 1 H-41534
3 Cotter Pin (

Rod Adapter Stud (-10) w/Nosepiece 1 7423 -10

1 Stud (Main Body) 1 H-41536
2 Nosepiece (-10) 1 H-41535
3 Cotter Pin (

3

/32" x 1") 2 HFG193

3

/32" x 1") 2 HFG193

MKIV Underdeck Unit 1 Parts List

Please read these instructions carefully before installing, servicing, or operating the equipment.
This manual may be modified without notice. See: www.harken.com/manuals for updated versions.

PLEASE SAVE THESE INSTRUCTIONS

MKIV UNDERDECK JIB REEFING & FURLING

Unit 1, 2, 3

Installation Manual – Intended for specialized personnel or expert users

5003/11-01-2012

Preassembly

Parts 4–5
Rigging Parts Check/Tools 6
Dimensions/Sailmaker's Instructions 7
Stay Length Deductions/Stay Into Foil Options 8

Hub Assembly

Deck Flange 9
Install Hub Assembly in Bow 10–11
Assemble Drum Components 11
Underdeck Lead Block 12

Preassembly

Top Foil Length (Unit 1) 13
Top Foil Length (Unit 2) 14
Top Foil Length (Unit 3) 15
Short Top Foil (Unit 1) 16
Short Top Foil (Unit 2) 17
Short Top Foil (Unit 3) 18
Foil Length Check 19

Assembly

Foils/Connectors 20–26
Halyard Swivel 26
Torque Tube Assembly 27
Rod Rigging 28
Attach Turnbuckle/Foils to Boat 29–31
Feeder/Final 32

Commissioning

Turnbuckle 33–34
Lead Line to Cockpit 35
Halyard Swivel Height/Angle 36
Halyard Restrainer/Tension 37

Operation

Halyard/Headstay Tension 38
Raise Sails/Storm Sails/Reefing 39–40
Secure Sail 40
Race Conversion 41

Maintenance

Clean/Lubricate/Inspect 42
Confirm Deck Flange/Tack Swivel Gap 42
Replace Line 42
Storage/Transporting 42
Remove Furler 42

Troubleshooting/Warranty

HFG629

7411.FOIL SET

7411.32

7411.31

H-36125A

MP-129

MP-129

MP-129

H-36125A

HFG343

HFG625

HFS1126

HFG680

H-39812

HFS1105

7411.30

7411.33

7411.31

7411.32

6

Description Order Part No.

Trim Cap Set w/o Screws 1 HFG680

6

Trim Cap Screw Set 1 HFG629

Trim Cap Screw 3 HFS1126

Halyard Swivel w/o Shackles 1 H-39812

®

Torlon

Ball Bearings 96 MP-129

Clip/Smalley Ring 2 H-36125A

Foil Set 1 7411.FOIL SET

Foil (7' / 2.13 m) Luff 6 7411.30
Foil (2' / 610 mm) Bottom 1 7411.33

Foil Screw Set 1 HFG343

Foil Screw 30 HFS1105

Connector Set w/o Bushings 1 HFG625

Connector (7" / 178 mm) 5 —
Connector Bottom (10.75" / 273 mm) 1 —

Connector Bushing Set 1 HFG295

Connector Bushing (Curved / Longer) 12 H-42062
Connector Bushing (Flat / Shorter) 12 H-42063

Connector w/Bushings 1 7411.31

Connector (7" / 178 mm) 1 —
Connector Bushing (Curved / Longer) 2 —
Connector Bushing (Flat / Shorter) 2 —

Connector w/Bushings Bottom 1 7411.32

Connector Bottom (10.75" / 273 mm) 1 —
Connector Bushing (Curved / Longer) 2 —
Connector Bushing (Flat / Shorter) 2 —

Connector Wedge Set 1 HFG299

Connector Wedge 14 H-39625

Feeder Set 1 H-39683

Feeder 1 H-35623B
Feeder Screw 1 HFS1129
Tab 1 H-35666A

Description Order Part No.

Instruction Manual 1 4656

7

Prefeeder 1 947

H-42062

H-42063

HFG295

H-39625

®

Loctite

Blue 1 833

®

Loctite

Red 2 HFG739

5200 Adhesive Set 1 HFG725

5200 Marine Adhesive Sealant 1 HFG722

Injector 1

HFG200
HFG201

Hex Keys

5 mm 1 HFG643

H-39683

HFG299

4656

4 mm 1 HFG640

2.5 mm 1 HCP1387

Description Order Part No.

Lead Block Kit 1 7404

HFG739

8

29 mm Outboard Lead Assembly 3 7403
57 mm Carbo Ratchet Assembly 1 7402
40 mm Carbo Assembly 1 7401
Horn Cleat 1 HCP168

Additional Lead Blocks

29 mm Carbo Stand-Up Fixed 1 349
Big Bullet Thru-Deck 1 131

Shackle (6 mm) 3 2110

833

HFG722

947

7

7404

349
131

8

Halyard Restrainer 1 945

HFG200 / HFG201

HFG643
HFG640

HCP1387

2110

945

7302

MKIV Underdeck Unit 1 45

Sheave/SS Inner Race Only 1 945ASSY
Clevis Pin (

5

/16" x 11/4") 1 SP-038
Bracket-Large 1 HCP394
Cotter Pin (

3

/32" x 3/4") 1 HFS181

Halyard Deflector 1 7302

MKIV Underdeck Unit 2 Parts List

HFG687 HFG686HFG688

HFS980

H-35665D

HFS980

H-35600C

H-35199E

HFS1052

1 2

1

2

Description Order Part No.

Top Cover Assembly w/Screws 1 HFG686

1

2

3

4

Top Cover 2 H-35665D
Top Cover Screw (M4 x .7 x 10MM) 2 HFS980

Bottom Flange Assembly w/Screws 1 HFG687

Flange 2 H-35600C
Bottom Flange Screw (M4 x .7 x 10MM) 2 HFS980

Guard Assembly 1 HFG688

Guard Set 2 H-35199E
Guard Screw (M6 x 1 x 40MM SHCS) 2 HFS1052

No. Description Order Part No.

Torque Tube Assembly 1 HFG928

1 Clamp 1 H-42346
1 Clamp Screw (M6 x 1 x 16MM SHCS) 4 HFS747

Hub Assembly 1 HFG924

1 Cotter Pin (
2 Clevis Pin (
3 Bearing Cap w/Insert 2 HFG933

A Bearing Cap 1 H-43231
B IGUS

4 Socket Head Cap Screws (M6 x 1 x 12MM) 4 HFS876

Ball Plug 5 H-33860A
Torlon
Delrin

5 Deck Flange 1 H-43100

5

/32" x 1.250") 4 HFS203

5

/8" x 1.460") 4 H-42397

®

Bushing 1 HCP1707

®

Ball Bearing (3/8") 28 MP-127

®

Ball Bearing (3/8") 134 MP-123

MP-127
H-33860A

H-33860A
MP-123

H-33860A
MP-123
H-33860A
MP-123

H-33860A
MP-123

3

HFG928

1

2

3

3

4

B

A

B

A

HFG924

4

Pin Measurements

*Grip

Length

*Pin measurements

are "Grip Length."

1

2

1

2

5

46 MKIV Underdeck Unit 2

4

3

2

7424 -12

3

7424 -17

5

1

7424 -12

5

7425 -17

No. Description Order Part No.

Rod Adapter Stud (-12) w/Nosepiece 1 7424 -12

1 Stud (Main Body) 1 H-41531
2 Nosepiece (-12) 1 H-41527
3 Cotter Pin (

Rod Adapter Stud (-17) w/Nosepiece 1 7425 -17

1 Stud (Main Body) 1 H-41531
2 Nosepiece (-17) 1 H-41526
3 Cotter Pin (

3

/32" x 1") 2 HFG193

3

/32" x 1") 2 HFG193

MKIV Underdeck Unit 2 Parts List

PLEASE SAVE THESE INSTRUCTIONS

7412.FOIL SET

7412.31

7412.32

HFG672

H-38028A

H-38028A

HFG348

MP-127

MP-127

MP-127

HFG626

HFG681

HFS1127

H-39794

HFS1106

7412.30

7412.33

7412.31

7412.32

6

Description Order Part No.

Trim Cap Set w/o Screws 1 HFG681

6

Trim Cap Screw Set 1 HFG672

Trim Cap Screw 3 HFS1127

Halyard Swivel w/o Shackles 1 H-39794

®

Torlon

Ball Bearings 92 MP-127

Clip/Smalley Ring 2 H-38028A

Foil Set 1 7412.FOIL SET

Foil (7' / 2.13 m) Luff 8 7412.30
Foil (2' / 610 mm) Bottom 1 7412.33

Foil Screw Set 1 HFG348

Foil Screw 38 HFS1106

Connector Set w/o Bushings 1 HFG626

Connector (9" / 229 mm) 7 —
Connector Bottom (13" / 330 mm) 1 —

Connector Bushing Set 1 HFG296

Connector Bushing (Curved / Longer) 16 H-42032
Connector Bushing (Flat / Shorter) 16 H-42033

Connector w/Bushings 1 7412.31

Connector (9" / 229 mm) 1 —
Connector Bushing (Curved / Longer) 2 —
Connector Bushing (Flat / Shorter) 2 —

Connector w/Bushings Bottom 1 7412.32

Connector Bottom (13" / 330 mm) 1 —
Connector Bushing (Curved / Longer) 2 —
Connector Bushing (Flat / Shorter) 2 —

Connector Wedge Set 1 HFG300

Connector Wedge 18 H-39487

Feeder Set 1 H-39559

Feeder 1 H-33931B
Feeder Screw 1 HFS1129
Tab 1 H-35671A

Description Order Part No.

Instruction Manual 1 4656

7

Prefeeder 1 947

®

Loctite

Blue 1 833

®

Loctite

Red 2 HFG739

5200 Adhesive Set 1 HFG725

5200 Marine Adhesive Sealant 1 HFG722

Injector 1

Hex Keys

6 mm 1 HFG644

HFG200
HFG201

HFG296

HFG300

H-42032

H-42033

H-39487

H-39559

5 mm 1 HFG643
4 mm 1 HFG640

MKIV UNDERDECK JIB REEFING & FURLING

Unit 1, 2, 3

Installation Manual – Intended for specialized personnel or expert users

Preassembly

Parts 4–5
Rigging Parts Check/Tools 6
Dimensions/Sailmaker's Instructions 7
Stay Length Deductions/Stay Into Foil Options 8

Hub Assembly

Deck Flange 9
Install Hub Assembly in Bow 10–11
Assemble Drum Components 11
Underdeck Lead Block 12

Preassembly

Top Foil Length (Unit 1) 13
Top Foil Length (Unit 2) 14
Top Foil Length (Unit 3) 15
Short Top Foil (Unit 1) 16
Short Top Foil (Unit 2) 17
Short Top Foil (Unit 3) 18
Foil Length Check 19

Assembly

Foils/Connectors 20–26
Halyard Swivel 26
Torque Tube Assembly 27
Rod Rigging 28
Attach Turnbuckle/Foils to Boat 29–31
Feeder/Final 32

Commissioning

Turnbuckle 33–34
Lead Line to Cockpit 35
Halyard Swivel Height/Angle 36
Halyard Restrainer/Tension 37

Operation

Halyard/Headstay Tension 38
Raise Sails/Storm Sails/Reefing 39–40
Secure Sail 40
Race Conversion 41

Maintenance

Clean/Lubricate/Inspect 42
Confirm Deck Flange/Tack Swivel Gap 42
Replace Line 42
Storage/Transporting 42
Remove Furler 42

Troubleshooting/Warranty

Please read these instructions carefully before installing, servicing, or operating the equipment.
This manual may be modified without notice. See: www.harken.com/manuals for updated versions.

5003/11-01-2012

4656

HFG739
HFG833

HFG722

947

HFG200/HFG201

HFG644
HFG643

HFG640

HCP1089

7

7404

2652

047

2117

944

7303

8

8

3 mm 1 HCP1089

Description Order Part No.

Lead Block Kit 1 7404

29 mm Outboard Lead Assembly 3 7403
57 mm Carbo Ratchet Assembly 1 7402
40 mm Carbo Assembly 1 7401
Horn Cleat 1 HCP168

Additional Lead Blocks

40 mm Carbo Stand-Up Fixed 1 2652

2.25" Thru-Deck 1 047

Shackle (8 mm) 3 2117
Halyard Restrainer 1 944

Sheave/SS Inner Race Only 1 944ASSY
Clevis Pin (

1

/4" x .9") 1 HFG467
Bracket-Small 1 HCP393
Cotter Pin (

1

/16" x 1/2") 1 HFS118

Halyard Deflector 1 7303

MKIV Underdeck Unit 2 47

MKIV Underdeck Unit 3 Parts List

HFG690 HFG689HFG691

MP-128
H-38168

4

H-38168
MP-116
H-38168
MP-116
H-38168

MP-116

HFS1060

H-35025D

HFS1060

1

H-35465C

H-33758E

2

HFS873

1 2

3

HFG929

1

2

3

3

B

A

4

B

A

Top Cover Assembly w/Screws 1 HFG689

1

2

3

4

4

Top Cover 2 H-35025D
Top Cover Screw (M5 x .8 x 12MM) 2 HFS1060

Bottom Flange Assembly w/Screws 1 HFG690

Flange 2 H-35465C
Bottom Flange Screw (M5 x .8 x 12MM) 2 HFS1060

Guard Assembly 1 HFG691

Guard Set 2 H-33758E
Guard Screw (M8 x 1.25 x 50MM SHCS) 2 HFS873

No. Description Order Part No.

Torque Tube Assembly 1 HFG929

1 Clamp 1 H-42967
2 Clamp Screw (M8 x 1.25 x 25MM SHCS) 4 HFS1107

Hub Assembly (3/4") 1 HFG925

1 Cotter Pin (
2 Clevis Pin (
3 Bearing Cap w/Insert 2 HFG935

A Bearing Cap 1 H-44674
B IGUS

4 Socket Head Cap Screws (M6 x 1 x 12MM) 4 HFS876

Ball Plug 5 H-38168

®

Torlon

Ball Bearing (1/2") 27 MP-128

®

Delrin

Ball Bearing (1/2") 128 MP-116

5 Deck Flange 1 H-44680

Hub Assembly (7/8") 1 HFG926

1 Cotter Pin (
2 Clevis Pin (
3 Bearing Cap w/Insert 2 HFG935

A Bearing Cap 1 H-44674
B IGUS

4 Socket Head Cap Screws (M6 x 1 x 12MM) 4 HFS876

Ball Plug 5 H-38168

®

Torlon

Ball Bearing (1/2") 27 MP-128

®

Delrin

Ball Bearing (1/2") 128 MP-116

5 Deck Flange 1 H-44680

Description Order Part No.

5

/32" x 1.250") 4 HFS203

3

/4" x 1.766") 4 H-42403

®

Bushing 1 HCP1684

5

/32" x 1.250") 4 HFS203

7

/8" x 1.958") 4 H-42404

®

Bushing 1 HCP1684

Pin Measurements

H-38168
MP-116

HFG925 (3/4")

HFG926 (7/8")

1

2

1

2

5

4

*Grip

Length

*Pin measurements

are "Grip Length."

3

2

1

3

7424 -12
7424 -17

7426 -22

5

5

7427 -30

48 MKIV Underdeck Unit 3

No. Description Order Part No.

Rod Adapter Stud (-22) w/Nosepiece 1 7426 -22

1 Stud (Main Body) 1 H-41812
2 Nosepiece (-22) 1 H-41811
3 Cotter Pin (
4 Stud Cap (

Rod Adapter Stud (-30) w/Nosepiece 1 7427 -30

1 Stud (Main Body) (not shown) 1 H-41814
2 Nosepiece (-30) 1 H-41813
3 Cotter Pin (
4 Stud Cap (

3

/32" x 13/4") 2 HFG319

7

/8") ID (not shown) 1 HFG303

3

/32" x 13/4") 2 HFG319

7

/8") ID (not shown) 1 HFG303

MKIV Underdeck Unit 3 Parts List

HFG672

H-39916

MP-128

MP-128

MP-128

H-39916

7413.10 FOILSET

HFG349

H-39751

HFS1127

H-39752

H-39392

7413.30

7413.31

H-42073
H-42074

6

Description Order Part No. (

Trim Cap

6

Top (with Holes) 1 H-39751
Bottom (with Pegs) 1 H-39752

Trim Cap Screw Set 1 HFG672

Trim Cap Screw 3 HFS1127

Halyard Swivel w/o Shackles 1 H-39392

Foil Set 1 7413.10 FOILSET

Foil (2'/610 mm) Bottom 1 7413.33
Foil Screw Set 1 HFG349

Connector Set 1 HFG627

Connector Bushing Set 1 HFG297

Connector Wedge Set 1 HFG324

Feeder with Screw and Tab 1 H-39756

®

Torlon

Ball Bearings 88 MP-128

Clip/Smalley Ring 2 H-39916

Foil (7' / 2.13 m) Luff 10 7413.30

Foil Screw 46 HFS1106

Connector (9
Bottom Connector (14" / 356 mm) 1 7413.32

Connector Bushing Top (Curved / Longer) 20 H-42073
Connector Bushing Bottom (Flat / Shorter) 20 H-42074

Connector Wedge 22 H-39487

Feeder 1 H-38332B
Feeder Screw 1 HFS1130
Tab 1 H-38372A

3

/4" / 248 mm) 9 7413.31

3

/4, 7/8)

7413.32

HFG297

Description Order Part No. (

Instruction Manual 1 4656

7

H-39756

HFG324

7413.33

HFG627

4656

HFG739

MKIV UNDER-DECK

Jib Reefing & Furling

Installation Manual

Unit 1, 2, 3

WARNING!: Strictly follow all instructions
to avoid an accident, damage to your vessel,
personal injury or death. See www.harken.com
for additional safety information.

833

HFG722

7

7404

2600

137

8

947

HFG200/HFG201

HFG647
HFG644

HFG640

HCP1089

MKIV Underdeck Unit 3 49

071

2124

945

7304

Prefeeder 1 947

®

Loctite

Blue 1 833

®

Loctite

Red 2 HFG739

5200 Adhesive Set 1 HFG725

5200 Marine Adhesive Sealant 1 HFG722

Injector 1

Hex Keys

10 mm 1 HFG647
6 mm 1 HFG644
4 mm 1 HFG640
3 mm 1 HCP1089

Description Order Part No.

Lead Block Kit 1 7404

8

29 mm Outboard Lead Assembly 3 7403
57 mm Carbo Ratchet Assembly 1 7402
40 mm Carbo Assembly 1 7401
Horn Cleat 1 HCP168

Additional Lead Blocks

57 mm Carbo Single Swivel 1 2600
Stainless Steel Eyestrap 1 137
Stand-Up Spring 1 071
Thru-Deck (2.25") (not shown) 1 HC7981

Shackle (10 mm) 3 2124
Halyard Restrainer 1 945

Sheave/SS Inner Race Only 1 945ASSY
Clevis Pin (
Bracket-Large 1 HCP394
Cotter Pin (

Halyard Deflector 1 7304

5

/16" x 11/4") 1 SP-038

3

/32" x 3/4") 1 HFS181

HFG200
HFG201

3

/4, 7/8)

This Page Intentionally Left Blank

UNIT 1 — Deck Drill Template

UNIT 1

Deck Drill Template

IMPORTANT! If you print this template from a computer file, measure

to confirm that template is the correct size before drilling.

2.362" (60 mm)

BOW

4.694"

(119.25 mm)

Deck Flange Diameter

3.7" (94mm)

Hole Saw Size
33/4" (95mm)

3.351"

(85.1 mm)

Ø 4.5" (114.3 mm)

Measure this distance to verify
that template printed correctly

3.464" (88 mm)

!

4.54" (115.4 mm)

MKIV Underdeck Unit 1 45

This Page Intentionally Left Blank

UNIT 2 — Deck Drill Template

UNIT 2

Deck Drill Template

IMPORTANT! If you print this template from a computer file, measure

to confirm that template is the correct size before drilling.

2.678" (68 mm)

Deck Flange Diameter

4.2" (106.5 mm)

5.28"

(134.1 mm)

3.698"

(93.9 mm)

BOW

Ø 5.032" (127.82 mm)

Measure this distance to verify
that template printed correctly

3.936" (100 mm)

Hole Saw Size
41/4" (110 mm)

5.07" (128.8 mm)

46 MKIV Underdeck Unit 2

!

This Page Intentionally Left Blank

UNIT 3 (3/4, 7/8) — Deck Drill Template

UNIT 3 (3/4, 7/8)

Deck Drill Template

IMPORTANT! If you print this template from a computer file, measure

to confirm that template is the correct size before drilling.

3.444" (87.5 mm)

BOW

Deck Flange Diameter

5.45" (138.5 mm)

Hole Saw Size
51/2" (140mm)

4.665"

(118.5 mm)

6.77"

(172 mm)

Ø 6.471" (164.36 mm)

Measure this distance to verify
that template printed correctly

5.2" (132.1 mm)

!

6.531" (165.9 mm)

MKIV Underdeck Unit 3 47

Corporate Headquarters

N15W24983 Bluemound Rd, Pewaukee, WI 53072 USA

Telephone: [phone] • Fax: [phone]

Web: www.harken.com • Online Catalog: www.harkenstore.com

1B Green Street, Brookvale, N.S.W. 2100, Australia

Telephone: [phone] • Fax: [phone]

Web: harken.com.au • Email: [e-mail]

ZA Port des Minimes, BP 3064, 17032 La Rochelle Cedex 1, France

Telephone: [phone] • Fax: [phone]

Via Marco Biagi, 14, 22070 Limido Comasco (CO) Italy
Telephone: [phone] • Fax: [phone]

30-36 Fanshawe Street, P.O. Box 1951, Auckland 1001, New Zealand

Telephone: [phone] • Fax: [phone]

Web: harken.co.nz • Email: [e-mail]

ul. Rydygiera 8, budynek 3A, lokal 101, I pi

Tel: [phone] • Fax: [phone]

Main Office and Harken Brandstore: Västmannagatan 81B

Telephone: [phone] • Fax: [phone]

Mailing address: Harken Sweden AB, Box 64, SE -440 30 Marstrand

Bearing House, Ampress Lane, Lymington, Hampshire S041 8LW, England

Telephone: [phone] • Fax: [phone]

Web: harken.co.uk • Email: [e-mail]

Email: [e-mail]

Harken Australia Pty, Ltd.

Harken France

Web: harken.fr • Email: [e-mail]

Harken Italy S.p.A.

Web: harken.it • Email: [e-mail]

Harken New Zealand, Ltd.

Harken Polska SP ZOO

ętro, 01-793 Warszawa, Poland

Web: harken.pl • Email: [e-mail]

Harken Sweden AB

SE-113 26 Stockholm Sweden

Web: harken.se • Email: [e-mail]

Harken UK, Ltd.

Please visit: http://www.harken.com/locator.aspx

to locate Harken dealers and distributors

Printed in USA 4656 01/14