STEP 2 - Placement of your SternMate™

A - Determine that the aft-most portion of the entire SternMate™ unit (incl. all components you may have chosen to use) is greater than 3/8" + (more is better) above the running surface once installed.

To make measurements, tape your paint paddle to the underside (beneath your designated SternMate™ location as shown) of your boat and allow it to extend aft several inches.

B - Ensure that the face of your transducer can be adjusted at least 3/4"+ above the running surface and 1/2" below. Your transducer assembly should be loosely through-fastened and centered on the SternMate™ Setback Plate (or other components) to determine latitude of vertical adjustment in this step.
C - Pencil trace around your SternMate™ upon determining the exact location for installation  you have found by completing A and B. Disassemble your SternMate™ and center the Mounting Plate on your bottom trace line. Adhere at that location. Scrub your transom with IPA. Wipe dry with clean cloth. Scrub back side of Mounting Plate with IPA. Wipe dry. Apply the 4 "Yellow      Dots” on the adhesive side of Mounting Plate to fully cover screw inserts. Avoid touching the clean Mounting Plate.
SternMate™ - Transducer Installation Instructions
(1) Lots of vertical adjustment range, not only in your transducer bracket, but with any optional bracket accessory. 

(2) Follow the "RULES" .

(3) Planning vertical adjustment of your transducer during the "locating" process is very important.

(4) Popsicle sticks ('buttering sticks") are used to determine an intallation height measurement of 3/8" + (photo 

(4) Initial trial optimization run: Adjust your transducer so the  face is approx. 1/4" above the running surface (photo B). Use the paint paddle to find this measurement.  Also use the paint paddle to ensure that the face of the transducer is on the same plane a your running surface. 
Transducer sounding was optimum regardless where SternMate and transducer  was installed on our test boat. An uninterrupted flow of water fore of the transducer is necessary.
Components in your SternMate™ Kit

(1)  Mounting Plate 
(1)  Housing 
(1)  Set-back Plate
(4)  #10 Nut Holders
(1)  Trim Snap                                            

(4)  ¾” x10x32 screws (mount Housing to Mounting Plate only)  
(1)  3/4" x10x32 screw (optional screw for fastening lanyard to SetBack Plate or Housing))
(4)  1 ½”x10x32 screws (mount Set-back Plate thru Housing to Mounting Plate)
(2)  7/8”x 10x32 (mount most transducer brackets directly to Housing) 
(2)  1 ½”x10x32 (mount most transducer brackets to Set-back Plate thru Housing to Mounting Plate)
(3)  #10x32 nylon-insert lock nuts    
(1)  Stainless steel wire lanyard
Reference: Transducer Installation Photos on SternMate™  (click images to enlarge)
click to enlarge
Why do we do it this way? SternMate™ effectively distances the transducer properly aftward from the transom up and away from the “trough” and into the rising displaced slipstream of water naturally created behind a fast moving boat. Elevating the transducer face into the aftward elevated slipstream...allowing the transducer to "surf", employs a unique corrective advantage toward optimizing your high speed sounding. 
The DUO™ bracket provides the same desired aftward setback as the Setback Plate in photo A. 
Gather the Following

  • Light wt. thread lock (opt.)                                        
  • Several clean cloths                                                       
  • 91% (IPA) Isopropyl Alcohol                                       
  • Single edge razor blade                                                
  • Strong tape (for paint paddle)
  • Your transducer(s) and its mounting bracket
Boat hull and air temperature: 65 deg. F + (18.4 C). In colder climates, artificial heat and canvas shrouding around the work area is acceptable. Heat can accelerate working time, cold will retard working time.
Familiarize yourself with these instructions and those provided by the manufacturer of your transducer prior to installation and follow them closely for best results. The installation is simple. Don't Rush It. Refer to our website or our office for assistance.

Transducer Location

Follow the proven basic "RULES" for the proper location of your external high speed transducer. Refer to the SternMate™ website.
Proceed to STEP 1.
STEP 1 - Prepare Your Transom

Scrub well, degrease, remove oxidation, scum, wax, mold release where you have chosen to install your SternMate™. DO NOT use petroleum based products. Scrub well with IPA before installation.

Gel coat - DO NOT sand or abrade. Ensure gelcoat is intact, in good condition w/o osmotic blistering.

Painted Aluminum - Remove paint to bare aluminum. Bare aluminum oxidizes quickly. Clean well with IPA immediately prior to installation. DO NOT sand metal.

Painted wood - Intact, well-coated, seasoned polyurethane finish. DO NOT sand. IPA scrub only.

Bottom/anti-fouling paint - Gently remove to gel coat or to metal surface. Scrub well with IPA.
Your transducer may be moved to other SternMate™ slots later for best optimization, as necessary. Trial fit and adequate vertical adjustment is important. 

Deadrise V-hull Installation - SternMate™ may be installed on the deadrise angle or parallel to the water (installer preference). 

Utilizing the paint paddle, reach of the transducer must be adequate to satisfy the requirements in A and B, which may determine how you will install your SternMate™. Installed on the deadrise, the transducer is rotated parallel to the water. Verify that the low side of the transducer follows the same vertical adjustment latitude in  sections A and B. (Some deadrise V-hulls require an optional aftward "set back" accessory, dependent upon your unique transom cant and transducer bracket reach).
Flat-bottom Skiff
Deadrise V-hull
clk to enlarge
STEP 3 - SternMate™ Adhesion

SternMate™ Adhesive Instructions can be found on the yellow card in your SternMate™ kit. Mix very well at room temperature. The adhesive is gap-filling (to 1/4"+) should the Mounting Plate not lie absolutely flat. Carefully"butter" the adhesive with wood paddles on the backside of the Mounting Plate over the yellow dots (thickness of 2-3 credit cards is adequate).

Keep adhesive away from the notch at the topside of the Mounting Plate by approximately 1/4". Spread adhesive evenly as represented in the photo. Keep the edges and the face side of the Mounting Plate free of adhesive. Keep hands clean.

Keep hands clean to avoid contaminating the Mounting Plate. Begin very careful clean up immediately upon positioning your MountingPlate while adhesive is still damp. The adhesive sets up quickly, so be diligent. Use dampened cloths with IPA to clean the area, particularly at the edges of the Mounting Plate. Use the edge of a clean wood adhesive paddle to remove "oozed" adhesive, if any, from the perimeter ofthe Mounting Plate. The completed installation should show no evidence of adhesive. You may tightly wrap an IPA dampened cloth over the end of a clean "butter" paddle to aggressively clean away any adhesive that may be evident at the joint. A single edge razor blade might be handy to cut away curing adhesive. USE ONLY IPA on or near your Mounting Plate. Other solvents will attack the material.
Paint paddle
  • Wood paint paddle
  • Paper towels
  • Helper (optional)
  • Sharp pencil

When the Mounting Plate has been "buttered"with adhesive, place it on the bottom pencil trace line. Press the Mounting Plate firmly and gently to the transom and twist a bit side to side to ensure complete adhesive contact between the transom and the Mounting Plate. Do not squeeze adhesive from the joint. Only slight loss should occur, if any, and can be easily cleaned away. The adhesive is thixotropic (thick and sticky) and should hold the plate in position. If it slips a bit, simply move it back into position.
Copyright © 2008 -2013 Nanticoke Maritime LLC  All rghts reserved
Following C Marine Industries
SternMate™ transducer mounting system can easily be installed on most all boats. Some of the types of boats that use transom-mounted transducers for fish-finders, depth-finders, sonar and fish locators are:

How  to mount a transducer on: All-Purpose Fishing Boats    Aluminum Fishing Boats    Fish and Ski   Bass Boats    Bowriders    Flat Boats    Bass boats    Center Console  Closed Bow Runabouts  Welded Boats   Center Console   Closed Bow Runabouts    Center Console    Closed Bow Runabouts    Cuddy Cabins    Deck Boats    Houseboats     Dinghies   Electric Boats    Multi-Hull Power Boats    Catamarans    Jet Boats   Performance Boats    Pontoon Boats    Stern Drive boats    Cruisers    Skiffs    I/O Inboard-Outboard Walkaround boats   Sailboats    Runabouts    Outboard boats    Electric boats    Row boats    Fishing boats     Fiberglass boats  Steel boats  Painted Wood boats   
Marine electronics manufacturers of fish-finder, transducers, depth-finder, sonar and fish locator, transducer mount equipment:​
EAGLE    Furuno    Garmin    Humminbird   Lowrance    Norcross Marine  Northstar Technologies SI-TEX    Raymarine    SIMRAD    Northstar    Tacktick    Uniden    Navionics    Standard Horizon   ​
Disclaimer: The aformentioned marine electronics manufacturers do not endorse SternMate products. 
P: (214) 295-5733

(1)  Adhesive                                                                      
(1)  Installation Instructions (refer to SternMate™ website)
(2)  Wood sticks 
(4) Adhesive dots (yellow      thread insert covers)

(1) #10 Phillips screw (lanyard to transom, if desired)  
Nanticoke Maritime LLC

Nanticoke Maritime LLC
         ...we're the folks who have changed the RULES
The "Original" SternMate™ Transducer Mounting System