Depth Finder


in_hull_transducer_P79.gif (7285 bytes)



The only installed instrument I need is the Raymarine ST40 depth finder. My Garmin GPSMAP 76S gives me everything else.


Why would you drill a hole in the bottom of your boat if you don't have to? If you are replacing an existing thru-hull 'ducer, have a wood or steel hull, or can't find a good spot to shoot thru the hull maybe it makes sense.

There are two types of transducers for the ST40. One requires that a hole be drilled in the bottom of the boat, the other is the In-hull type. In-hull transducers (a.k.a. shoot-through) are placed directly on the inside of the hull. I chose the  AIRMAR Model P79 transducer because it installs quick and easy. 

If you browse the archives of the forum you'll see lots of discussion on in-hull vs. thru-hull transducers. In the H260 the location next to the bilge pump is the preferred location. Go to this link for more on this advantages and disadvantages of this type transducer. 

Raymarine says the transducer should be expoxied to the hull but some people have just used toilet ring wax to stick it to the bottom of the bilge. That makes it removable. I used the wax to test it first then after I was sure it would work, I used 3M4200 sealant to secure it in place. 

I installed the transducer next to the bilge pump. It has worked without a hitch. The install instructions are easy to follow.


The ARMAR-79 'ducer works with virtually all displays and is sufficient for the average boat.