Oceanus 400 transducer location?

[Rattlenebang]

G'day all, I have a new-to-me Oceanus 400 that came with an non-functioning depthsounder so I installed a new one, but the transducer seems unable to shoot through the hull (it's supposed to be able to). The cable that came with it isn't very long and so the furthest forward I was able to mount it is about half way between the center seat/plumbing cabinet and companionway ladder. There's an opening in the floor pan there, perhaps a foot from the centreline where I was just able to squeeze the transducer in and glue it directly to the hull. No good. Doesn't seem to be able to transmit through it.
Is the hull very thick there? I'm a little at a loss where to install the thing as it seems wherever I do I'll need to cut a hole through the floor pan to reach the hull itself. I'm not sure where the old transducer is; the previous owner said something about in the bow, but my transducer cable simply isn't that long.

 

[Ralph Johnstone]

Welcome to the site @Rattlenebang.

Being a master of hindsite, I can only recommend that you should have tested the hull location before attaching the depth sounder to the hull. Hopefully, the sounder isn't attached with anything too strong.

See post #9 :

drilling holes thru the hull ...

I am about to drill a 2" hole to install a depth/speed transducer, and wondering what I might find. is it solid or cored beneath the v-berth? thanks ...

forums.sailboatowners.com

Fill the baggy underwater in a sink to ensure there's no air bubbles in it and then proceed. Don't know what you used for glue but silicone sealant, without bubbles, is good. Some people use a toilet bowl bee's wax gasket. All good.

 

[Rattlenebang]

I've already lifted it: used a bit of thickened epoxy that was more thickener than epoxy and it came off with a bit of prying. Baggy wouldn't have work as not enough room, and I wonder whether there would be enough loss going through water/hull/water that I'd get a false result anyway. These transducers are supposed to be glued solid to the hull so the hull transmits the vibrations, and anything between the transducer and hull could compromise that.

 

[JoeWhite]

There is nothing special about its cable. You can use 4 conductor 24 gauge nickle plated twisted and shielded microphone wire one piece from one end to the other.

 

[Ralph Johnstone]

and I wonder whether there would be enough loss going through water/hull/water that I'd get a false result anyway.

All you're looking for at that point would be anything that looks like a signal. It's only a test.

If you say you can't get a baggy near your desired point, try the plumber's bee's wax as both a test medium and then a permanent installation. I've used silicone butmany people on this site swear by bee's wax.

 

[Rattlenebang]

Thanks everyone. I carved out a hole in the floor pan 18" away from the centreline and that seemed to do the trick. I bit of 5-min epoxy and it reads fine. I guess the hull is too thick that close to the keel.

There is nothing special about its cable. You can use 4 conductor 24 gauge nickle plated twisted and shielded microphone wire one piece from one end to the other.

You'd think so but an "official" extension is over $70!