Seafarer Transducer

Hello again

To provide an overview - I have been on and off working on a fiberglass hull of a Starley Sea Nymph to eliminate some small but significant leaks etc and my attention has now been brought to bear on this transducer. Since the above photos I have knocked the head of the sounder through the hull. The fairing in the above pic seems sound enough. The sounder is useless and was in place to keep hull water tight. Pervious owner had installed a different fishfinder beside this one - epoxy'd to hull on inside. Sadly, this finder came to the same fate and was cut and left in situ.

The Seafarer depth sounder (old type with the repeater unit that had spinning dial) This was long removed from the boat by the time I got it and the person responsible wisely hack-sawed through the sounder head and left everything relating to the transducer in place assuming everything below the waterline to be sealed. I was not to know this and in my curiosity have now a partly dismantled head in my hand and a 13mm hole in the hull. My option are:

a) remove fairing, sand and do a proper hull patch.
b) Reinstall broken head and seal with epoxy until leaks are impossible or
c) Replace old head with new one (available by NASA) and try to use as a fishfinder

Up until recently I was only interested in sealing the hole but now I'm thinking considering I am a fisherman I will be using a fishfinder at some stage - why not try to modify whats there already?

My research has uncovered that I can, at least, install a new depth finder using the parts available from NASA but I would like to explore the possibility of using a modern display unit showing the profiles and detail of the bottom with a new, albeit coaxial transducer installed in the old through-the-hull fairing.

Are modern fishfinders compatible with coaxial transducers or are these only really useful with a very basic depth finder. Are there kits available to upgrade the sounder head to a unit that can be installed into the old fairing but plugged directly into a Garmin or a similar display unit?

I would appreciate any knowledge anyone might have here and I will provide more info if needed.

Thanks
P

 

Thru hull transducers are optional for all modern fish finders and will fit a 13 mm hole.
Both single and dual frequency models are available (wide and narrow beam).

 

So can I take from this that a modern f/f head could be made to fit the hole? I have sourced a replacement (made by NASA) that will more then likely fit this fairing perfectly - the only problem being the cable is coaxial. It will not fit the back of a Garmin et al.

:?:

 

Garmin uses their own sockets and plugs to prevent you from buying the peripherals elsewhere. For the transducer you have in mind you just need signal and ground. Maybe they have an adapter cable, but it probably is ridiculously expensive.

 

Most transducers are made by Airmar.
I used an Apelco 7 pin and a garmin 6 pin transducer with two Eagle color fish finders. Using the schematic of the plug, and I bought a 6 pin socket plug for one and used the 7 pin socket plug for the other and wired it into the Eagle Fisheasy 340c in parallel with its existing plug.
I found the wiring diagrams for both on airmar site and they are a pure Airmar product even though packaged with the garmin and apelco head units.

For accuracy, the khz of the transducer speaker needs to match the head unit.

Some schematic info
https://goo.gl/photos/g6Y3xgoHPFnA6Tuo6