How to Mount a Depth Finder on an Aluminum Boat

How to Mount a Depth Finder on an Aluminum Boat
Finding a location to mount a depth finder on any boat is a chore. You could spend a full day moving the depth finder's transducer---the sounding device that relays depth information back to the display---in order to find a perfect spot for readings. Aluminum hulls complicate the process, because aluminum causes a loss of signal strength. In fact, standard transducers often lack enough signal strength to penetrate an aluminum hull. Your best option is to mount the transducer to your boat's transom.

Instructions

Difficulty: Moderate

Things You’ll Need:
  • Depth finder
  • Transducer mounting board
  • Drill
  • Sandpaper
  • Stainless bolts and nuts
  • Marine silicone sealant
  • Transducer
  • Zip ties
Step 1
Identify the location on the transom where you will install a transducer mounting board. According to the Ultimate Bass Fishing Resource Guide, mount the board between rows of rivets. When the boat is moving, the rivets create water turbulence, which would interfere with readings. The surface should also be flat, so that the mounting board sits flush against it. You can buy a transducer mounting board from a specialty fishing retailer or online from big box fishing retailers.
Step 2
Drill holes in the hull to align with the holes in the transducer mounting board. Select a drill bit that lets the bolt just fit through with little or no gaps. Sand any metal barbs from the holes so the hardware mounts flush.
Step 3
Clean the hull where the transducer mounting board sits. Coat the back of the board in a layer of marine silicone sealant. Bolt the mounting board to the hull. Coat the bolt with silicone sealant and fill the drilled holes completely with sealant. Stainless steel hardware lasts the longest; make sure you buy stainless if the mounting board didn't come with hardware.
Step 4
Wait for the silicone sealant to dry, and then mount the depth finder's transducer. Screw the transducer's stainless steel screws directly to the mounting board. Take care, as the heads on stainless steel screws strip out easily; use a screwdriver instead of a screw gun to prevent stripping.
Step 5
Mount the display unit on the boat's control station. Connect the transducer to the display unit using the supplied wire connector. Use zip ties to keep the wire secured inside your boat's hull.

Tips & Warnings

 
Newer depth finders, like the AlumaDucer by Vexilar, are designed to transmit through an aluminum hull. Using one of these means you won't have to drill through your boat's hull. Just find the perfect location and glue the transducer in place.
 
Using a transducer mounting board means no holes to patch when you sell the boat. You would simply remove the depth finder from the board and leave the board on the boat.
 
Don't break off the transducer when loading the boat.
 
Items displayed on the screen may not be under the boat, so don't depend on the depth finder to provide 100 percent accurate spatial information.

Article Written By Bryan Hansel

Bryan Hansel is a freelance photographer and kayaking guide who began writing in 1993. His outdoors articles appear on various websites. Hansel holds a Bachelor of Arts in English and religion from the University of Iowa.

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