Pub. 988-0152-101
www.eaglesonar.com
& Cuda 250i S/Map
Fish-finding Sonar & GPS
Installation and Operation
Instructions
Copyright © 2005 LEI-Eagle
All rights reserved.
No part of this manual may be copied, reproduced, republished,
transmitted or distributed for any purpose, without prior written
consent of Eagle Electronics. Any unauthorized commercial
distribution of this manual is strictly prohibited.
Eagle
®
, Cuda® 250 S/Map and Cuda® 250i S/Map are registered
trademarks of LEI.
eXitSource Database, copyright 2001-2005 Zenrin Co.
Ltd. Exit Authority and eXitSource are trademarks of
Zenrin Co. Ltd.
Eagle Electronics may find it necessary to change or end our policies,
regulations, and special offers at any time. We reserve the right to do so
without notice. All features and specifications subject to change without
notice. All screens in this manual are simulated. On the cover: Cuda
250 S/Map shown. Other models covered in the manual are similar.
For free owner's manuals and the most current information on
this product, its operation and accessories,
visit our web site:
www.eaglesonar.com
Eagle Electronics
P.O. Box 669
Catoosa, OK USA 74015
Printed in USA.
i
Table of Contents
Section 1: Read Me First!........................................................ 1
Capabilities and Specifications: Cuda 250 S/Map ........................ 3
How Your Sonar Works ................................................................ 5
How Your GPS Works .................................................................. 6
Introduction to GPS and WAAS................................................... 7
How to use this manual: typographical conventions .................. 9
Arrow Keys.............................................................................. 10
Keyboard ................................................................................. 10
Menu Commands .................................................................... 10
Instructions = Menu Sequences ............................................. 10
Section 2: Installation & Accessories.................................. 13
Preparations................................................................................ 13
Transducer Installation.............................................................. 13
Recommended Tools and supplies.......................................... 14
Transom installation........................................................... 14
Trolling motor installations................................................ 14
Shoot-through hull installations ........................................ 14
Selecting a Transducer Location............................................ 15
How low should you go?.......................................................... 16
Shoot-thru-hull vs. Transom Mounting ................................. 17
Hulls With Floatation Materials............................................ 26
Testing Determines Best Location......................................... 27
Shoot-thru-hull Installation ................................................... 29
Power and Cable Connections ................................................ 31
Mounting the Sonar Unit: In-Dash or Bracket ..................... 33
Portable Sonar Installation .................................................... 38
Installing the Batteries .......................................................... 38
Portable Transducer Assembly .............................................. 40
Section 3: Basic Sonar Operation ....................................... 43
Keyboard ..................................................................................... 43
Memory........................................................................................ 45
Menus .......................................................................................... 45
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Main Menu .............................................................................. 45
Sonar Menu ............................................................................. 46
Pages ........................................................................................... 48
Sonar Quick Reference .......................................................... 50
Sonar Operations ........................................................................ 51
Fish Symbols vs. Full Sonar Chart ........................................ 55
Other Free Training Aids ....................................................... 55
Section 4: Sonar Options & Other Features..................... 57
ASP (Advanced Signal Processing) ..................................... 57
Alarms ......................................................................................... 58
Depth Alarms .......................................................................... 58
Zone Alarm .............................................................................. 60
Fish Alarm............................................................................... 61
Chart Speed................................................................................. 61
Depth Cursor............................................................................... 63
Depth Range - Automatic ........................................................... 63
Depth Range - Manual................................................................ 64
FasTrack .................................................................................. 65
Fish I.D. (Fish Symbols & Depths) ......................................... 65
FishTrack ................................................................................. 67
Grayline
..................................................................................... 68
Overlay Data ............................................................................... 69
Ping Speed & HyperScroll....................................................... 70
Reset Options .............................................................................. 72
Sensitivity & Auto Sensitivity.................................................... 72
Automatic Sensitivity ............................................................. 73
Set Keel Offset ............................................................................ 74
Sonar Color Mode........................................................................ 76
Sonar Page & Sonar Chart Display Options ............................. 76
Full Sonar Chart ..................................................................... 76
Split Zoom Sonar Chart.......................................................... 77
Digital Data/Chart .................................................................. 78
Sonar Simulator.......................................................................... 79
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Stop Chart ................................................................................... 79
Surface Clarity............................................................................ 80
Zoom Pan..................................................................................... 82
Section 5: Sonar Troubleshooting ....................................... 83
Section 6: Basic GPS Operations ......................................... 87
Keyboard ..................................................................................... 87
Power/lights on and off ............................................................... 88
Main Menu .................................................................................. 89
Pages ........................................................................................... 90
Sonar Page .............................................................................. 91
Satellite Status Page .............................................................. 91
Navigation Page...................................................................... 93
Full Map Page ......................................................................... 96
Map with Sonar Page.............................................................. 98
GPS Quick Reference ............................................................. 99
Find Your Current Position...................................................... 100
Selecting Any Map Item With the Cursor ............................... 102
Set a Waypoint.......................................................................... 102
Create Waypoint on Map .................................................. 104
Navigate To a Waypoint ........................................................... 104
Set Man Overboard (MOB) Waypoint...................................... 105
Navigate to Cursor Position on Map........................................ 106
Navigate to a Map Place........................................................... 108
Creating and Saving a Trail..................................................... 108
Displaying a Saved Trail .......................................................... 110
Navigating Trails...................................................................... 111
Visual Trailing ...................................................................... 111
Navigate a Trail .................................................................... 112
Cancel Navigation..................................................................... 114
Section 7: Advanced GPS Operations ............................... 115
Find Distance from Point to Point ........................................... 115
Icons........................................................................................... 116
Create Icon on Map............................................................... 116
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Delete an Icon ....................................................................... 117
Navigate to an Icon............................................................... 118
Routes........................................................................................ 119
Create and Save a Route ...................................................... 119
Delete a Route ....................................................................... 122
Edit a Route .......................................................................... 122
Navigate a Route................................................................... 123
Trails ......................................................................................... 125
Delete a Trail ........................................................................ 125
Edit a Trail Name ................................................................. 126
Utilities...................................................................................... 126
Alarm Clock........................................................................... 126
Sun/Moon Rise & Set Calculator.......................................... 127
Trip Calculator...................................................................... 127
Trip Down Timer................................................................... 127
Trip Up Timer ....................................................................... 127
Waypoints.................................................................................. 127
Delete a Waypoint................................................................. 127
Edit a Waypoint .................................................................... 127
Waypoint Name................................................................. 127
Waypoint Symbol .............................................................. 128
Waypoint Position ............................................................. 128
Section 8: System & GPS Setup Options .......................... 131
Alarms ....................................................................................... 131
Auto Satellite Search................................................................ 132
Coordinate System Selection.................................................... 133
Map Fix ..................................................................................... 136
Customize Page Displays ......................................................... 137
Customize Position Page ...................................................... 137
Customize Map or Navigation Page..................................... 138
GPS Simulator .......................................................................... 138
Initialize GPS............................................................................ 140
Map Auto Zoom......................................................................... 140
v
Map Data................................................................................... 141
Earth Map Detail .................................................................. 141
Pop-up Map Info.................................................................... 141
Fill Water With White .......................................................... 141
Map Overlays (Range Rings; Lat/Long Grid) ...................... 142
Map Datum Selection ............................................................... 142
Map Detail Category Selection................................................. 143
Map Orientation ....................................................................... 144
Overlay Data ............................................................................. 145
Pop-up Help............................................................................... 148
Reset Options ............................................................................ 148
Screen Contrast and Brightness .............................................. 149
Set Language ............................................................................ 150
Set Local Time .......................................................................... 150
Show WAAS Alarm................................................................... 151
Software Version Information.................................................. 152
Sounds and Alarm Sound Styles.............................................. 153
Track Smoothing....................................................................... 153
Trail Options ............................................................................. 154
Delete All Trails .................................................................... 155
Update Trail Criteria........................................................ 155
Specific Trail Options........................................................ 156
Trail Visible/Invisible and Other Trail Options .................. 157
Units of Measure....................................................................... 157
vi
WARNING!
A CAREFUL NAVIGATOR NEVER RELIES ON ONLY ONE METHOD
TO OBTAIN POSITION INFORMATION.
CAUTION
When showing navigation data to a position (waypoint), a GPS unit will show
the shortest, most direct path to the waypoint. It provides navigation data to the
waypoint regardless of obstructions. Therefore, the prudent navigator will not
only take advantage of all available navigation tools when traveling to a waypoint, but will also visually check to make sure a clear, safe path to the waypoint
is always available.
WARNING!
When a GPS unit is used in a vehicle, the vehicle operator is solely responsible for operating the vehicle in a safe manner. Vehicle operators
must maintain full surveillance of all pertinent driving, boating or flying conditions at all times. An accident or collision resulting in damage
to property, personal injury or death could occur if the operator of a
GPS-equipped vehicle fails to pay full attention to travel conditions and
vehicle operation while the vehicle is in motion.
1
Section 1: Read Me First!
How this manual can get you out on the water, fast!
Welcome to the exciting world of digital sonar and GPS! We know
you're anxious to begin finding fish, but we have a favor to ask. Before
you grab the unit and begin installing it, please give us a moment or
two to explain how our manual can help you get the best performance
from your combination fish finder and GPS receiver.
First, we want to thank you for buying a Eagle sonar/GPS unit.
Whether you're a first time user or a professional fisherman, you'll discover that your unit is easy to use, yet capable of handling demanding
navigation and sonar tasks.
Our goal for this book is to get you on the water fast, with a minimum
of fuss. Like you, we'd rather spend more time boating or fishing and
less time reading the manual!
So, we designed our book so that you don't have to read the whole thing
from front to back for the information you want. At the start (or end) of
each segment, we'll tell you what content is coming up next. If it's a
concept you're already familiar with, we'll show you how and where to
skip ahead for the next important topic. We've also made it easy to look
up any tips you may need from time to time. Here's how:
The manual is organized into 8 sections. This first section is an introduction to the Cuda 250 sonar and GPS. It tells you the basics you
need to know before you can make the unit look below the surface to
find some fish.
Section 2 will help you install your unit, as well as the transducer (the
most important part of any sonar installation). We'll also tell you about
some of the available accessories.
Section 3 covers Basic Sonar Operation. It will show you how easy it is
to run your sonar, right out of the box.
2
This section features a one-page Sonar Quick Reference. (If you've already jumped ahead and figured out how to install the unit
yourself, and you just can't wait any longer, turn to the Quick
Reference on page 50 and head for the water with your unit!)
When you come to a sonar menu command on the unit's screen, you can
look it up in the manual by skimming over the table of contents, looking it
up in the manual's index, just flipping through Section 3 or scanning
through the sonar setup options in Section 7.
If you're having difficulty with your sonar, you can find an answer to
the most common problems in Section 5, Sonar Troubleshooting.
The manual switches from sonar to navigation in Section 6, which introduces you to Basic GPS Operations. This section features a one-
page GPS Quick Reference on page 99.
Section 6 contains short, easy-to-scan GPS lessons that follow one another in chronological order. They're all you'll need to know to find your
way on the water quickly.
When you come to a GPS menu command on the screen, you can look it
up in the manual by skimming over the table of contents or index, just
flipping through Section 6 or scanning through the setup options in
Section 7.
This unit is ready to use right out of the box, but you can fine tune and
customize its operation with dozens of options. Since sonar is the unit's
key feature, we put the main sonar options in Section 3. Some options,
such as screen brightness settings, affect both sonar and GPS operations. We describe how to use those common options along with GPS
options in Section 7, System Setup and GPS Setup Options. Section 7 is
organized in alphabetical order.
Finally, in Section 8, we offer Supplemental Material, including war-
ranties and customer service information, and a handy index.
Now, if you're into the fine details, glance over the next segment on
specifications to see just how much sonar and GPS power your unit con-
3
tains. It's important to us (and our power users), but, if you don't care
how many watts of power the unit has, or how many waypoints it can
store, skip ahead to important information on how sonar works, on page
5.
Capabilities and Specifications: Cuda 250 S/Map
General
Display:............................ High Contrast Film SuperTwist LCD with
16-level grayline. Diagonal viewing area: 3.5"
(8.9cm).
Resolution:...................... 160 pixel x 240 pixel resolution. 38,400 total
pixels.
Backlighting:.................. LED backlit screen with multiple lighting lev-
els; backlit keypad.
Input power:................... 10 to 17 volts DC.
Current drain: ............... 170 ma lights off; 250 ma lights on.
Case size:......................... 5.8" H x 4.3" W x 2.5" D (14.7 cm H x 10.8 cm
W x 6.6 cm D) sealed, waterproof; suitable for
saltwater use.
Back-up memory: .......... Built-in memory stores GPS data for dec-
ades. User settings are stored when unit is
turned off.
Languages:...................... 10; menu languages selectable by user.
Sonar
Frequency:...................... 200 kHz.
Transducer:...................... A Skimmer
transducer comes packed with
your sonar unit. Its 20° cone angle offers a
wide fish detection area of up to 60º with
high sensitivity settings. Operates at boat
speeds up to 70 mph (61 kts).
Transmitter: ................... 800 watts peak-to-peak; 100 watts RMS.
4
Sonar sounding
depth capability: ........... 600 feet (180 meters). Actual capability de-
pends on transducer configuration and installation, bottom composition and water conditions. All sonar units typically read deeper
in fresh water than in salt water.
Depth display:................ Continuous display.
Audible alarms: ............. Deep/shallow/fish/zone.
Automatic ranging:....... Yes, with instant screen updates.
Auto bottom track:........ Yes
Zoom bottom track: ...... Yes.
Split-screen zoom:......... Yes.
Surface water temp: ..... Yes, built into transducer.
GPS
Receiver/antenna: ......... Internal 12 parallel channel GPS/WAAS.
Position updates: .......... Every second.
Position points: ............. 1,000 waypoints; 1,000 event marker icons.
Man Overboard:............. MOB feature precisely marks man overboard
location with special icon, then automatically
displays navigation data to that position.
Audible alarms: ............. Arrival/off-course/destination passed/anchor.
Graphic symbols for
waypoints or event
marker icons: ................. 42.
Routes:............................. 100; up to 100 waypoints per route.
Plot Trails: ...................... 10 savable; up to 9,999 points per trail.
Zoom range:.................... 40 ranges; 0.02 to 4,000 miles.
5
NOTICE!
The storage and operation temperature range for your unit is from
-4 degrees to +167 degrees Fahrenheit (-20 degrees to +75 degrees
Celsius). Extended storage or operation in temperatures higher or
lower than specified will damage the liquid crystal display in your
unit. This type of damage is not covered by the warranty. For more
information, contact the factory's Customer Service Department;
phone numbers are listed on the last page.
How Your Sonar Works
Sonar has been around since the 1940s, so if you already know how it
works, skip down to read about the relatively new technology of GPS.
But, if you've never owned a sonar fish finder, this segment will tell you
the underwater basics.
Sonar is an abbreviation for SOund NA
vigation and Ranging, a technology developed during World War II for tracking enemy submarines. A
sonar consists of a transmitter, transducer, receiver and display. In
simple terms, here's how it finds the bottom, or the fish:
The transmitter emits an electrical impulse, which the transducer converts into a sound wave and sends into the water. (The sound frequency
can't be heard by humans or fish.) The sound wave strikes an object
(fish, structure, bottom) and bounces back to the transducer, which
converts the sound back into an electrical signal.
The receiver amplifies this return signal, or echo, and sends it to the
display, where an image of the object appears on the scrolling sonar
chart. The sonar's microprocessor calculates the time lapse between the
transmitted signal and echo return to determine the distance to the
object. The whole process repeats itself several times each second.
Your sonar unit can record a log of the sonar signals that scroll across
the screen and save them in its memory. (These recordings are also
called sonar charts or sonar graphs.)
6
You can replay this sonar log in the unit using the Sonar Simulator function. You can save several different sonar log files, erase 'em and record
new ones, over and over again.
How Your GPS Works
You'll navigate faster and easier if you understand how this unit scans
the sky to tell you where you are on the earth — and, where you're going. (But if you already have a working understanding of GPS receivers
and the GPS navigation system, skip on ahead to Section 2, Installation
& Accessories on page 13. If you're new to GPS, read on, and you can
later impress your friends with your new-found knowledge.)
First, think of your unit as a small but powerful computer. (But don't
worry — we made this unit easy to use, so you don't need to be a computer expert to find your way!) The unit includes a keypad and a screen
with menus so you can tell it what to do. The screen also lets the unit
show your location on a GPS plotter, as well as point the way to your
destination.
This unit uses an internal antenna/receiver module, which makes the
whole system work something like your car radio. But instead of your
favorite dance tunes, this receiver tunes in to a couple of dozen GPS
satellites circling the earth. (It will also listen in to the WAAS satellites
in orbit, but more about that in the upcoming segment introducing you
to GPS and WAAS.)
Your unit listens to signals from as many satellites as it can "see" above
the horizon, eliminates the weakest signals, then computes its location
in relation to those satellites. Once it figures its latitude and longitude,
the unit plots that position on the GPS screen. The whole process takes
place several times a second!
Another portion of the unit's onboard memory is devoted to recording GPS
navigation information, which includes waypoints, event marker icons,
trails and routes. This lets you look back the way you came, and retrace
your path.
7
Think of this data storage like the hard drive memory in a computer or a
tape in a cassette tape recorder. You can save several different GPS data
files, erase 'em and record new ones, over and over again.
Introduction to GPS and WAAS
Well, now you know the basics of how the unit does its work. You might
be ready to jump ahead to Section 2, Installation, on page 13, so you
can mount your unit and plug in the power. Or you might want to see
how our text formatting makes the manual tutorials easy to skim. If
that's the case, move on to "How to Use This Manual" on page 9. But, if
you want to understand the current state of satellite navigation, look
over this segment describing how GPS and its new companion WAAS
work together to get you where you're going.
The Global Positioning System (GPS) was launched July 17, 1995 by
the United States Department of Defense. It was designed as a 24hour-a-day, 365-days-a-year, all weather global navigation system for
the armed forces of the U.S. and its allies. Civilian use was also available at first, but it was less accurate because the military scrambled
the signal somewhat, using a process called Selective Availability (SA.)
GPS proved so useful for civilian navigation that the federal government discontinued SA on May 2, 2000, after the military developed
other methods to deny GPS service to enemy forces. Reliable accuracy
for civilian users jumped from 100 meters (330 feet) under SA to the
present level of 10 to 20 meters (about 30 to 60 feet.)
Twenty-four satellites orbit 10,900 nautical miles above the Earth,
passing overhead twice daily. A series of ground stations (with precisely
surveyed locations) controls the satellites and monitors their exact locations in the sky. Each satellite broadcasts a low-power signal that identifies the satellite and its position above the earth. Three of these satellites
are spares, unused until needed. The rest virtually guarantee that at
least four satellites are in view nearly anywhere on Earth at all times.
8
The system requires signal reception from three satellites in order to
determine a position. This is called a 2D fix. It takes four satellites to
determine both position and elevation (your height above sea level —
also called altitude). This is called a 3D fix.
Three satellites are required to determine a 2D fix.
Remember: the unit must have a clear view of the satellites in order to
receive their signals. Unlike radio or television signals, GPS works at
very high frequencies. These signals can be easily blocked by trees,
buildings, an automobile roof, even your body.
Like most GPS receivers, this unit doesn’t have a compass or any other
navigation aid built inside. It relies solely on the signals from the satellites to calculate a position. Speed, direction of travel, and distance
are all calculated from position information. Therefore, in order for the
unit to determine direction of travel, you must be moving and the
faster, the better. This is not to say that it won’t work at walking or
trolling speeds — it will. There will be more "wandering" of the data
shown on the display.
GPS alone is plenty accurate for route navigation, but the U.S. Federal
Aviation Administration has special aircraft navigation needs that go
9
beyond basic GPS. So, the FAA has developed a program to boost GPS
performance with its Wide Area Augmentation System, or WAAS. The
FAA commissioned the system on July 11, 2003.
WAAS is designed to increase GPS accuracy to within 7.6 meters vertically
and horizontally, but it consistently delivers accuracies within 1-2 meters
horizontal and 2-3 meters vertical, according to the FAA. It does this by
broadcasting correction signals on GPS frequencies. Your unit automatically receives both GPS and WAAS signals.
There, however, are some fringe areas of the U.S., including parts of
Alaska, that do not yet receive robust WAAS coverage. Continued WAAS
development is planned to extend WAAS coverage in the years to come.
WAAS boosts the accuracy of land GPS navigation, but the system is
designed for aircraft. The satellites are in a fixed orbit around the
Equator, so they appear very low in the sky to someone on the ground
in North America. Aircraft and vessels on open water can get consistently good WAAS reception, but terrain, foliage or even large man-made
structures can sometimes block the WAAS signal from ground receivers.
You will find that using your GPS receiver is both easy and amazingly
accurate. It is easily the most accurate method of electronic navigation
available to the general public today. Remember, however, this receiver
is only a tool. Always have another method of navigation available,
such as a map or chart and a compass.
Also remember that this unit will always show navigation information
in the shortest line from your present position to a waypoint, regardless
of terrain! It only calculates position, it can’t know what’s between you
and your destination, for example. It’s up to you to safely navigate
around obstacles, no matter how you’re using this product.
How to use this manual: typographical conventions
Many instructions are listed as numbered steps. The keypad and arrow
"keystrokes" appear as boldface type. So if you are in a real hurry, you
10
can skim the instructions and pick out what menu command to use by
finding the boldface command text. The following paragraphs explain
how to interpret the text formatting for those commands and other instructions:
Arrow Keys
The arrow keys control the movement of dotted cross-hair lines on your
plotter screen called the cursor. The arrow keys also control a horizontal line depth cursor on the sonar screen. The arrow keys help you move
around the menus so you can execute different commands. They are
represented by symbols like these, which denote the down arrow key,
the up arrow, the left arrow and the right arrow: ↓ ↑ ← →.
Keyboard
The other keys perform a variety of functions. When the text refers to a
key to press, the key is shown in bold, sans serif type. For example, the
"Enter/Icons" key is shown as
ENT and the "Menu" key is shown as MENU.
Menu Commands
A menu command or a menu option will appear in small capital letters, in
a bold sans serif type like this:
ROUTE PLANNING. These indicate that you are
to select this command or option from a menu or take an action of some
kind with the menu item. Text that you may need to enter or file names
you need to select are show in italic type, such as trail name.
Instructions = Menu Sequences
Most functions you perform with this unit are described as a sequence
of key strokes and selecting menu commands. We've written them in a
condensed manner for quick and easy reading.
For example, instructions for navigating a trail would look like this:
1. From the Plotter Page, press
MENU|MENU|↓ to MY TRAILS|ENT.
2. Press ↓ to Trail 1|
ENT|→|↓ to NAVIGATE|ENT.
3. You are asked to wait while it converts the trail into a route.
11
4. The wait message disappears and the unit begins showing navigation information along the trail. Now, begin moving and follow
your unit's directions.
Translated into complete English, step 1 above would mean: "Start on
the Plotter Page. Press the Menu key twice. Next, repeatedly press (or
press and hold) the down arrow key to scroll down the menu and select
(highlight) the My Trails menu command. Finally, press the Enter key."
Step 2 would mean: "Press the down arrow key repeatedly to scroll to
the trail named Trail 1, and press Enter. Next, press the right arrow
key and then the down arrow key to highlight the Navigate command,
then press Enter."
12
Notes
13
Section 2: Installation
Preparations
You can install the sonar and GPS systems in some other order if you
prefer, but we recommend this installation sequence:
CAUTION:
You should read over this entire installation section before drilling any holes in your vehicle or vessel!
1. Determine the approximate location for the sonar/GPS unit, so you
can plan how and where to route the power/transducer cable. This will
help you make sure you have enough cable length for the desired configuration.
2. Determine the approximate location for the transducer and its cable
route.
3. Determine the location of your battery or other power connection,
along with the power cable route.
4. Install the transducer and route the transducer cable to the sonar/GPS unit.
5. Route the power cable from the unit's location to an appropriate
power source and connect it there.
6. Connect the transducer/power cable to the unit and mount the sonar/GPS unit to the bracket.
Transducer Installation
These instructions will help you install your Skimmer
transducer on a
transom, on a trolling motor or inside a hull. Please read all instructions before proceeding with any installation.
14
Your Skimmer transducer typically comes packaged with a one-piece
stainless steel bracket for mounting it to the transom of your boat. The
optional trolling motor mount uses a one-piece plastic bracket with an
adjustable strap. These are "kick-up" mounting brackets. They help prevent damage if the transducer strikes an object while the boat is moving.
If the transducer does "kick-up," the bracket can easily be pushed back
into place without tools.
Read these instructions carefully before attempting the installation.
Determine which of the installation methods is right for your boat.
Remember, the transducer location and installation is the most
critical part of a sonar installation.
Recommended Tools and supplies
If you prefer the option of routing the cable through the transom, you
will need a 5/8" drill bit.
NOTE:
The following installation types also call for these recommended
tools and required supplies that you must provide (supplies listed
here are not included):
Transom installation
Tools include: two adjustable wrenches, drill, #29 (0.136") drill bit, flathead screwdriver. Supplies: high quality, marine grade above- or below-
waterline sealant/adhesive compound.
Trolling motor installations
Tools: two adjustable wrenches, flat-head screwdriver. Supplies: plastic
cable ties.
Shoot-through hull installations
Tools: these will vary depending on your hull's composition. Consult your
boat dealer or manufacturer. Other tools are a wooden craft stick or
similar tool for stirring and applying epoxy, and a paper plate or piece
of cardboard to mix the epoxy on. Supplies: rubbing alcohol, 100 grit
15
sandpaper, specially formulated epoxy adhesive available from LEI (see
ordering information on the inside back cover). A sandwich hull also
requires polyester resin.
Selecting a Transducer Location
1. The location must be in the water at all times, at all operating speeds.
2. The transducer must be placed in a location that has a smooth flow of
water at all times. If the transducer is not placed in a smooth flow of
water, interference caused by bubbles and turbulence will show on
the sonar's display as random lines or dots when the boat is moving.
NOTE:
Some aluminum boats with strakes or ribs on the outside of the
hull create large amounts of turbulence at high speed. These boats
typically have large outboard motors capable of propelling the boat
at speeds faster than 35 mph. Typically, a good transom location on
aluminum boats is between the ribs closest to the engine.
3. The transducer should be installed with its face pointing straight
down, if possible. For shoot-thru applications: Many popular fishing
boat hulls have a flat keel pad that offers a good mounting surface. On
vee hulls, try to place the transducer where the deadrise is 10° or less.
Vee pad hull (left); Vee hull (right). A pod style transducer is shown
here, but the principle is the same for Skimmers inside a hull.
4. If the transducer is mounted on the transom, make sure it doesn't
interfere with the trailer or hauling of the boat. Also, don't mount it
closer than approximately one foot from the engine's lower unit. This
will prevent cavitation (bubble) interference with propeller operation.
Deadrise less than 10
°
Pad
Strakes
16
5. If possible, route the transducer cable away from other wiring on the
boat. Electrical noise from engine wiring, bilge pumps and aerators
can be displayed on the sonar's screen. Use caution when routing the
transducer cable around these wires.
Good and poor transducer locations.
How low should you go?
For most situations, you should install your Skimmer transducer so
that its centerline is level with the bottom of the boat hull. This will
usually give you the best combination of smooth water flow and protection from bangs and bumps.
CAUTION: Clamp the transducer cable to transom near
the transducer. This will help
prevent the transducer from
entering the boat if it is
knocked off at high speed.
Good location
Good location
Poor angle
Poor location
Good
location
17
Align transducer centerline with hull bottom.
However, there are times when you may need to adjust the transducer
slightly higher or lower. (The slots in the mounting brackets allow you
to loosen the screws and slide the transducer up or down.) If you frequently lose bottom signal lock while running at high speed, the transducer may be coming out of the water as you cross waves or wakes.
Move the transducer a little lower to help prevent this.
If you cruise or fish around lots of structure and cover, your transducer
may be frequently kicking up from object strikes. If you wish, you may
move the transducer a little higher for more protection.
There are two extremes you should avoid. Never let the edge of the
mounting bracket extend below the bottom of the hull. Never let the
bottom – the face – of the transducer rise above the bottom of the hull.
Shoot-thru-hull vs. Transom Mounting
In a shoot-thru-hull installation, the transducer is bonded to the inside
of the hull with epoxy. The sonar "ping" signal actually passes through
the hull and into the water. This differs from a bolt-thru-hull installation (often called "thru-hull"). In that case, a hole is cut in the hull and a
specially designed transducer is mounted through the hull with a
threaded shaft and nut. This puts the transducer in direct contact with
the water.
Transom
Hull bottom
Transducer
centerline
18
Typically, shoot-thru-hull installations give excellent high speed operation and good to excellent depth capability. There is no possibility of
transducer damage from floating objects, as there is with a transommounted transducer. A transducer mounted inside the hull can't be
knocked off when docking or loading on a trailer.
However, the shoot-thru-hull installation does have its drawbacks.
First, some loss of sensitivity does occur, even on the best hulls. This
varies from hull to hull, even from different installations on the same
hull. This is caused by differences in hull lay-up and construction.
Second, the transducer angle cannot be adjusted for the best fish arches
on your sonar display. (This is not an issue for flasher-style sonars.)
Lack of angle adjustment can be particularly troublesome on hulls that
sit with the bow high when at rest or at slow trolling speeds.
Third, a transducer CAN NOT shoot through wood and metal hulls.
Those hulls require either a transom mount or a thru-hull installation.
Fourth, if your Skimmer transducer has a built in temp sensor, it will
only show the temperature of the bilge, not the water surface temp.
Follow the testing procedures listed in the shoot-thru-hull installation
section at the end of this lesson to determine if you can satisfactorily
shoot through the hull.
TRANSOM TRANSDUCER ASSEMBLY AND MOUNTING
The best way to install the transducer is to loosely assemble all of the
parts first, place the transducer's bracket against the transom and see if
you can move the transducer so that it's parallel with the ground.
1. Assembling the bracket. Press the two small plastic ratchets into the
sides of the metal bracket as shown in the following illustration. Notice
there are letters molded into each ratchet. Place each ratchet into the
bracket with the letter "A" aligned with the dot stamped into the metal
bracket. This position sets the transducer's coarse angle adjustment for a
14° transom. Most outboard and stern-drive transoms have a 14° angle.
19
Align plastic ratchets in bracket.
2. Aligning the transducer on the transom. Slide the transducer
between the two ratchets. Temporarily slide the bolt though the
transducer assembly and hold it against the transom. Looking at the
transducer from the side, check to see if it will adjust so that its face
is parallel to the ground. If it does, then the "A" position is correct for
your hull.
If the transducer's face isn't parallel with the ground, remove the
transducer and ratchets from the bracket. Place the ratchets into the
holes in the bracket with the letter "B" aligned with the dot stamped
in the bracket.
Reassemble the transducer and bracket and place them against the
transom. Again, check to see if you can move the transducer so it's
parallel with the ground. If you can, then go to step 3. If it doesn't,
repeat step 2, but use a different alignment letter until you can place
the transducer on the transom correctly.
Dot
20
Insert bolt and check transducer position on transom.
3. Assembling the transducer. Once you determine the correct posi-
tion for the ratchets, assemble the transducer as shown in the following figure. Don't tighten the lock nut at this time.
Assemble transducer and bracket.
4. Drilling mounting holes. Hold the transducer and bracket assembly
against the transom. The transducer should be roughly parallel to the
ground. The transducer's centerline should be in line with the bottom
of the hull. Don't let the bracket extend below the hull!
Ratchets
Nut
Metal
washer
Metal washer
Bolt
Rubber
washers
21
Mark the center of each slot for the mounting screw pilot holes. You
will drill one hole in the center of each slot.
Drill the holes using the #29 bit (for the #10 screws).
Position transducer mount on transom and mark mounting holes.
Side view (left) and seen from above (right).
5. Attaching transducer to transom. Remove the transducer from
the bracket and re-assemble it with the cable passing through the
bracket over the bolt as shown in the following figures.
Route cable over bolt and through bracket. Side view (left) and seen
from above (right).
Attach the transducer to the transom. Slide the transducer up or
down until it's aligned properly with the bottom of the hull as shown
in the preceding and following figures. Tighten the bracket's mounting screws, sealing them with the sealant/adhesive compound.
Transom
Transom
22
Adjust the transducer so that it's parallel to the ground and tighten
the nut until it touches the outer washer, then add 1/4 turn. Don't
over tighten the lock nut! If you do, the transducer won't "kick-up" if
it strikes an object in the water.
Align transducer centerline with hull bottom and attach to transom.
6. Route the transducer cable through or over the transom to
the sonar unit. Make sure to leave some slack in the cable at the
transducer. If possible, route the transducer cable away from other
wiring on the boat. Electrical noise from the engine's wiring, bilge
pumps, VHF radio wires and cables, and aerators can be picked up by
the sonar. Use caution when routing the transducer cable around
these wires.
WARNING:
Clamp the transducer cable to the transom close to the
transducer. This can prevent the transducer from entering the boat if it is knocked off at high speed.
If you need to drill a hole in the transom to pass the connector through,
the required hole size is 5/8".
Caution:
If you drill a hole in the transom for the cable, make sure it is located above the waterline. After installation, be sure to seal the
hole with the same marine grade above- or below-waterline sealant/adhesive used for the mounting screws.
Flat-bottom hull
Deep-"vee" hull
Bottom
of
hull
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