Airmar M260 In Hull Transducer

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Transducer shell

Transducer box


My old 600 kw transducer was mounted on port bilge access and was partially obstructed by the keel which I think diminished the performance.  I could read the bottom down to about 300′ consistently and had poor resolution and constant electrical interference from some unknown source. As with all though hull transducers it was vulnerable to fouling and needed cleaning fairly often. I finally got fed up with the poor performance and decided to upgrade it.

The new installation is under the forward starboard berth which was easy to access and provided a smooth unobstructed location for the transducer to shoot straight down.

The box was cut using a combination of table saw, jig saw and hand saw then shaped with a belt sander to make it level fore and aft as well as to hull deadrise. Then epoxied in place using Marine Tex.

The cable provided is just the right length for the run which goes though the cabinetry and conduit aft to the aft cabin behind the drawers.  Then across under the bridge deck to the access behind the stove.  Finally up behind the helm bulkhead to the sounder, a Lowrance HD-7 Plotter/Sounder.

The box is filled with propylene glycol antifreeze (sold commonly as Marine/RV Antifreeze).

Performance is outstanding based on my initial tests.  The new M260 is 1kw and is paired with a Lowrance HD7. It  shows good bottom detail at 50 kHz down to 1,740 ft (so far) and at 200kHz down to about 400′. Bait balls and individual fish arches are showing up clearly now which is important to me because we fish a lot.

So far I am loving it and will try to add some screen shots from the Lowrance what I can.

Jim Johns

Savannah, #23



Finished Installation



This is 200 kHz showing good bottom detail at just under 300′ with bait ball and scattered fish marks. Shows better when photo is viewed enlarged.