Harken 7410.11 User Manual

MKIV UNDERDECK JIB REEFING & FURLING

Unit 0

Installation Manual – Intended for specialized personnel or expert users

Preassembly

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

Hub Assembly

Install Hub Assembly in Bow 9
Under-Deck Lead Block 10

Preassembly

Top Foil Length 11
Short Top Foil 12
Foil Length Check 13

Assembly

Foils/Connectors 14–20
Halyard Swivel 20
Torque Tube Assembly 21
Rod Rigging 22
Attach Turnbuckle/Foils to Boat 23–24
Feeder/Final 25

4427 01/14

Commissioning

Turnbuckle 26–27
Lead Line to Cockpit 28
Halyard Swivel Height/Angle 29

Halyard Restrainer/Tension 30

Operation

Halyard/Headstay Tension 31
Raise Sails/Storm Sails/Reefing 32–33
Secure Sail 33
Race Conversion 33

Maintenance/Troubleshooting

Clean/inspect 34
Replace Line 34
Storage/Transporting/Remove 34
Troubleshooting 35
Parts List 36–37
Drilling Template 38

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

Safety Precautions/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.

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/

g

h

manuals for general warnings and instructions.

f

b

c

a

e

d

1

2

Size Check

1. Check headstay in chart below.

Part No. Size Wire Size Rod Size

7410.11 Unit 0

Parts Descriptions

Hub Assembly

a) Bridge Fairlead Assembly
b) Ball Spool Guard Assembly

2 MKIV Underdeck Unit 0 07/14/10

c) Keeper
d) Deck Plate
e) Tack Shackle

3

/16", 7/32"

5 mm, 6 mm

-4, -6

4.37 mm, 5.03 mm

Standard

Headstay Length

38'4"

11.7 m

f) Torque Tube
g) Torque Tube Screws
h) Foil Clamp

Max.

Headstay Length

45' 4"

13.8 m

Preassembly Sizing Check

10

9

8

7

6

3

4

3

5

Online Product Registration

www.harken.com/FurlingWarranty

11

C

D

B

A

Unit Part No. A B C D

0

7410.11

1

/2"

5

140 mm

325/32"

96 mm

57/16"

138 mm

629/32"

175 mm

Will Drum Fit in Bow?

Note: See dimensions above. Unit requires a connection to underdeck chainplate for stay loads.
See page 38 for deck plate dimensions.

Furler Requires Drained Compartment

Harken’s Underdeck Furler is designed to keep much of the water from entering the bow compartment. Water
will drip through the furler when it rains or when sailing in heavy weather. The furling compartment must drain.

Upper Unit

1) Bottom Foil

2) Feeder

07/14/10 MKIV Underdeck Unit 0 3

3) Connector Bushing

4) Bottom Connector

5) 7' (2.13 m) Foil

6) Connector Wedge

7) Connector Screws

8) Connector

9) Halyard Swivel

10) Trim Cap Screws

11) Trim Cap

Preassembly Parts

Foil Screws

Hub Assembly

Bottom

Connector

Connectors

Halyard Swivel

Feeder

2.5, 3, 5 mm
Hex Keys

7' (2.13 m)

Foils

2' (610 mm)

Bottom Foil

Plastic Connector

Wedges

Connector Bushings

Trim Cap Screws

Bow Shackles

Prefeeder

Trim Cap

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.

5200

Adhesive

Injector

Red Loctite

®

Main Components

Part No. Quantity Description

HFG951 1

H-39923 1

Hub assembly with foil clamp

Halyard swivel

Foils (Standard Package)

Part No. Quantity Description

7410.30 5

7410.33 1

7'(2.13 m) foil

2'(610 mm) Botton foil

Tools

Quantity Description

1 Each

4 MKIV Underdeck Unit 0

2.5, 3, 5 mm Hex keys

Line Specifications

Forward Ø Min Break Strength Aft Ø

3

/16" (5 mm) 1300 lb (590 kg)

Other Components

Part No. Quantity Description

7410.31 4

7410.32 1

HFG294 1

HFG298 1

HFG341 1

HFG679 1

HFG629 1

947 1

H-39713 1

2110 3

HFG725 1

HFG739 2

6.5" (165 mm) Connector

10" (254 mm) Bottom Connector

Connector bushing set (10-H-42067/10-H-42068)

Plastic connector wedge set (12-H-39625)

Foil screw set (26-HFS1105)

Trim cap set (H-37335/H-37336)

Trim cap screw set (3-HFS1126)

Prefeeder

Feeder with screw and tab

6 mm Bow shackles

Injector, 1 oz. 5200 Adhesive (HFG722)

®

Red Loctite

(for foil screws)

1

/4" (6 mm)

Preassembly Rigging Parts Check/Tools

1. Turnbuckle components are not included and
must be purchased separately.

2. Rod rigging requires Harken rod adapter stud.

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

3

4. Furling Line - Use

/16 to 1/4" (5 to 6 mm). To figure
line length, measure the distance from the furler to
the furling cleat. Add 15' (4.5 m).

7404 Lead Block Kit

(Sold Separately)

131

349

Recommended Furling
Compartment Lead Blocks

Unit Turning Thru-Deck

0 349 131

Tools You Will Need

ROD RIGGING

Harken Rod Adapter

Stud Required

(Sold Separately)

7420 -4
7421 -6

Rod Adapter Stud

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.

5

3

Unit Drill Ø

0

1

2

7

4

8

12

1

/8"

(3 mm)

15

16

18

19

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

6

9

1. Long tape measure 6. Side cutters 11. Center punch 16. Hole saw 41/4" (110 mm)*

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

1

4. Drill bits

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

*Requires some beveling of bottom edge of deck hole to provide a good fit. Alternatively a smaller hole may be used to fashion a socket in deck to conform
to ball shape. This may improve appearance and reduce amount of water that enters. A 4

09/17/10 MKIV Underdeck Unit 0 5

/8" (3 mm) 9. Slotted/Phillips screwdrivers 14. Metal straight edge 19. 6 mm bolts, nuts, and washers

10

11

13

14

1

/2" (115 mm) hole saw may also be used if no beveling is desired.

thickness. Minimum thread

engagement must be 9 mm.

17

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 30).
If luff of sail is not long enough to put halyard swivel near top of

headstay foil, a pendant must be added. See page 29.

Tack Setback

Note setback for tack shackle and cut the sail accordingly.

B

A

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 18–24" (450–600 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

Make sure tack and head shackles fit sail

A

rings. The minimum inside dimensions
of standard head and tack shackles are:

E

Unit A B

1

0

1

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

B

Suncover

7410.11 Furls in one direction only.

IMPORTANT! Suncover must be installed on starboard side of sail.

C

D

F

Unit Part No. A B C D E F

0 7410.11

3

/4"

3

96 mm

61/4"

158 mm

119/64"

33 mm

15

/64"

6 mm

345/16"

817 mm

319/32"

91.5 mm

6 MKIV Underdeck Unit 0

Preassembly Rigging Options — Turnbuckle

The stay runs up the center of the MKIV Unit
0 Underdeck furler. It does not attach to the
furler in any way. Choose one of the follow­ing three turnbuckle locations based upon
diameter of turnbuckle body and access to
the turnbuckle below deck. The interior of
the furler components are shown below.

A

B

Unit A B C D E F G H

7

/16"

1

0

36.4 mm

101/8"

258 mm

1"

25.4 mm

71/2"

190.5 mm

51/2"

140.5 mm

17/8"

47.6 mm

25/16"

58.6 mm

11/2"

38.1 mm

C

D

E

F

G

H

Turnbuckle Options

Turnbuckle Below Furler

Make sure that the upper stud wrench
flats are accessible. If necessary, the bridge
fairlead assembly can be lowered below the
turnbuckle to allow access to wrench flats.

07/14/10 MKIV Underdeck Unit 0 7

Preassembly Turnbuckle Options

Turnbuckle inside torque tube

Set up a pendant below making sure
to have a turnbuckle toggle.

Use a swage to swage turnbuckle
located just above the lower unit.
Check turnbuckle fit inside torque
tube. Requires a “third hand” to adjust.

Turnbuckle above swage

On smaller size wires 3/16" (4 mm)
a small turnbuckle should fit. Check
dimensions above for clearance.

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 22.

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 0

Assembly Deck Plate

71°

–

73°

Note: Deck plate angle
matches a stay angle of
72° when compared to
deck. Angles can vary
between 71° and 73°. If
deck does not fall within
these angles, shims must
be made using structural
adhesive to avoid exces­sive pressure on deck
and deck bearings.

Tip: Run line through fairlead
and dead end line into spool
before mounting lower unit.

Carefully locate center point in deck to locate deck plate. Line from mast to underdeck
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. Mark center hole for drilling large hole.

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
plate 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.

Use 6 mm screws, washers, locknuts and deck sealant to fasten lower unit to deck.

3

Note: There must be a minimum of

/8" (9 mm) thread engagement into deck flange.

MKIV Underdeck Unit 0 9

Assembly Under-Deck Lead Block

Mount lead block so furling line is 90° to
hub assembly.

90°

Mount thru-deck block. Be sure to angle
it toward stanchion lead block.

10 MKIV Underdeck Unit 0

UNIT 0

Preassembly Unit 0—Top Foil Length

Measure A and add to this chart
and length chart below

Inches mm

A

B .4* 10*

E 24 610

F 14 359

G

Total A+B+E+F+G

*Add 1" (25 mm) if using a Halyard
Deflector.

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

Example–If result from Step 3 is:

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

500 inches “D” = 420 inches

12,000 mm “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 underside of deck 14 359

Length Chart

Dimensions Inches mm

.40*

Pin-to-Pin Length

10*

E

F

*Add 1" (25 mm) if using a Halyard Deflector.

MKIV Underdeck Unit 0 11

Preassembly Short Top Foil

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.

/8" (162 mm)

3

63/8" (162 mm) No special treatment required.

/8" (159–117 mm)

5

/4"–4

1

6

1

/4"–45/8" (159–117 mm) Do not use plastic bushing

6

Cut-Offs

Do Not Use

above top connector.

/2 (63 mm)

/2" (38 mm)

1

2" (51 mm)

2

/2" (13 mm)

1

1" (25 mm)

1

1

Cut-Offs

Do Not Use

21/2"–1/2" (63–13 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

2

/2"

(63 mm)

2"

(51 mm)

1

/2"

1

(38 mm)

1"

(25 mm)

1

/2"

(13 mm)

1. Initial
top foil
cut length

(143 mm)

(130 mm)

(117 mm)

(105 mm)

(92 mm)

55/8"

1

/8"

5

45/8"

1

/8"

4

35/8"

2. Cut through
middle hole in
top foil.*

Resulting Top

Foil Length Length

41/16"

(103 mm)

39/16"

(90 mm)

31/16"

(78 mm)

29/16"

(65 mm)

21/16"

(52 mm)

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

4. Shorten
connector

(83 mm)

(83 mm)

(83 mm)

(76 mm)

(70 mm)

31/4"

31/4"

31/4"

3"

23/4"

5. Shorten
trim cap

No

No

No

Yes

Yes

/2" (114–89 mm) 6

1

Cut-Offs

/2"–3

1

4

Do Not Use

41/2"–31/2" (114–89mm) Do not use plastic bushing

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

/8" (86–67 mm)

5

/8"–2

3

3

3

/8"–25/8" (86–67 mm) Do not use plastic bushing

3

Cut-Offs – Do Not Use

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

12 MKIV Underdeck Unit 0

Cut-Off

Do Not Use

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

middle hole is preserved.

/2" (13 mm)

1

Under

Under 1/2" (13 mm) Eliminate top foil and run foil higher

in drum assembly.