In hull depth transducers

Has anyone tried an in-hull installation on a BCC? I’m interested in a 50kHz depth only unit that would be direct mounted to the hull without an ‘oilbath’. Looking at the Airmar P79 and wondering if anyone has found other options to consider. Looks like the hull thickness is about 1/2 inch but deadrise is an issue. Cheers, Ray

I installed the Raymarine ST60 Depth[200kHz] with the Airmar P79 transducer which has worked very well getting depth readings up to 500’. Prior to that I had a Standard Horizon depth instrument with a much lower power rating[50kHz?] installed in an oil bath which gave limited range and often lost the signal completely. Usually could not read deeper than 60’.

Hope this helps,

Ron Thompson
Ho’okahiko 97

Thanks for that, Ron. I think I understand that the power rating (in watts?)is a different criteria than the frequency(in kHz). I’ll look at the ST60 head for power output. Thanks again, Ray

My response will be of limited use to you, as I am not sure of the power rating or frequency of my depth sounder, which is a DMI instrument (if you would like, I can advise you later this weekend when I will be out to the boat).

In any event, when I acquired Dioscouri (hull #064; previously “Sandpiper”) she had (and still has) an in-hull transducer, but it is installed in an oil bath. It has always worked very well.

Since acquiring the BCC, I have installed a Furuno multi-function unit, which has a separate transducer (not an in-hull transducer). I use that instrument pretty much all the time, which interferes with the operation of the DMI. However, if the Furuno unit is turned off, the DMI (with in-hull transducer) still works perfectly. Because I don’t use if often, I don’t recall precisely its range, but I’m quite sure it is beyond 500’.

Let me know if you would like me to provide you with any specs at a later date.


Hi Gary, No need for follow up information. I do appreciate your input though. BTW, where in the hull is your oil bath mount?

Gee Gary , I did the thru hull instalation with the “Standard Coms” depth sounder , and really not have had , any complications from that inside hull transducer location .

I followed the , build a dam , with clay, then “pot” the transducer in an epoxy lake , this has worked well for me , so far !

I haven’t tested it to chart soundings , as yet , but when I set the “Low” depth alarm , it does seem to alert me , when I am in shallow water ?

My only problem with the alarm is that it is not loud enough, as with my Furano Radar Proximity alarm , is also deficient in an auditory loud alarm , Drats !!!

I’ve had a Raytheon Z117 in hull connected to a Raytheon ST40 for 12
years. Lose the depth at around 500’ but feel, at that point, that I have
enough clearance…otherwise, has worked just

On Tue, Aug 28, 2012 at 8:51 PM, BCC Forums wrote:

Tom Harrer
S/V Whitewings III

My in-hull transducer is mounted in the locker under the port settee, at the forward end.