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Q1: on a 2009 150 MONTAUK can an in-hull SONAR transducer be installed in the cockpit sump?

BACKSTORY
I plan to install a structure-scan SONAR transducer on the transom of my 2009 150 MONTAUK, and move the existing SONAR transducer into the cockpit sump or onto a secondary area in the that is accessible by removing a cap in the seat. The SONAR transducer to be affixed with epoxy.

Modern transom mount transducers do an excellent job with structure scan sounders. The transducers must be mounted and adjusted well which can take a few tries. The result can be exceptional.

Johnetaberiii wrote:Q1: on a 2009 150 MONTAUK can an in-hull SONAR transducer be installed in the cockpit sump?

Your plan is not a good idea.

The Boston Whaler boat hull is a Unibond hull with high density structural foam filling all internal space between the hull and the hull liner. The presence of the foam causes the transmission of SONAR signals to be stopped, so you cannot use a SONAR transducer that is trying to shoot-through the hull.

The only option for installing a SONAR transducer somewhere other than the transom on a Unibond hull would be to install a transducer designed for mounting through a large hole in the hull. However, even that is not particularly workable on a typical Unibond hull. On some models--usually larger boats--Boston Whaler has provided a specific area in the construction of the hull where the foam will be excluded. Instead of foam this area (usually a small cube or rectangular area) will be filled with a putty. This area is called a "putty box." You can install a through-hull bottom-mounted transducer and drill the necessary large hole through the putty box. The purpose of the putty box is to create a non-foam surrounding area so there is no possibility of ingress of water into the interior foam of the hull.

Definitely NOT recommended.

It should be your goal to avoid cutting, drilling or making any additional holes in the hull so as to avoid the possibility of water penetration.