Siting through hull depth transducer

[maxcampbell]

OK, I've bitten the bullet and bought a NASA Target depth sounder and through-hull fitting kit.

I'd like to start planning where to fit the transducer. I can't fit it on the centreline (because the boat's built on a wooden keel / keelson assembly) and the deadrise forward of the (long) keel is steep.

How far away from the keel does it have to be? How important is verticality, given that we'll be healing most of the time anyway?

The boat's all wood (skin = ply), apart from a chunk of lead along most of the bottom of the keel.

 

[rob2]

Difficult to give a definitive answer without knowing the boat intimately! You can cut the end of the tube at an angle to get the transducer upright. The maximum angle at which a transducer works varies from model to model - do NASA give a working angle? Either way, it will work best and equally on both tacks if it is upright to the waterline. Choose a site where the keel will not obscure its view of the seabed when heeled and away from aerated/disturbed water flow, with easy access for maintenance. The oil bath may require topping up every few years.

Rob.

 

[NormanS]

Presumably with a wooden hull, the transducer has to be installed through the hull. Usually a fairing block is used to let it face straight down. The bumph with the kit should give an idea of the angle of the transmissions, so that should give you an idea for clearing the keel. Other than that, it's good to have it as far forward as possible. Compromises, compromises.

 

[sailorman]

keep it vertical forward of the keel in clean water & off set port or stbd to suit conditions, so the beam ark can spread full beam

 

[VicS]

You might like to also read the instructions from Seafarer for fitting their similar transducer. They are a little more detailed than the Nasa instructions.

Seafarer used to supply an automatic change over switch so that two transducers could be fitted, one either side, when it was not possible to fit one on the centreline

References to "tubes" and "oil baths" in posts above do not apply to through hull mounting

SEAFARER 3 FITTING INSTRUCTIONS

 

[maxcampbell]

SEAFARER 3 FITTING INSTRUCTIONS

Very helpful, thanks.

 

[simonfraser]

My depth transducer is siliconed to the inside of my epoxy ply trimaran, works just fine.

P.s. you might like the sailing vid I posted today

 

[maxcampbell]

P.s. you might like the sailing vid I posted today

I tried to watch it - fast boat off B'sea - but ended up with a tiny window & a very grainy image. Looked for it from YouTube search & couldn't find it.

Thanks re tip about in-hull. What thickness ply you got?

 

[simonfraser]

Some one has fixed the vid link

My hull is no more than 12mm max.

Stick it on with bluetack, you just don't want any air and it will work.

Now you gona find out what quality ply the builder used
Might vary with location too.

 

[maxcampbell]

Now you gona find out what quality ply the builder used

I know the quality, 'cos I was the builder Shouldn't be any voids, and it's 6mm, plus glass cloth & epoxy, and some fairing filler. I may well try it.