In well transducers

[BruceB]

I have purchased a Garmin 340C for the hull I am awaiting. It comes with a transom monted transducer but I would like a Hull mounted one
The only place to put on in a Humber is inside the well right in front of the outboard. Will the turbulance cause any problems with the prop and/or will I get good performance mounted within six inches of the hull edge with the transducer?
My intention would be to drill a hole at the front of the well and sikafix the transducer into the hull unless this is a bad idea for performance etc.
The transducer sticks down about an inch as far as I can see from photos which slightly worries me.....

Or are the thru hull versions OK for this application?

[eilean mor]

Hi Bruce, I'm not up on the technicalities, but; in several sailing boats that I've owned/ used; I've mounted through hull transducers inside; putting them into 'oil filled sealed tubes'- putting some form of access/screw thread at the top so I can get to the transducer if needed, and glassed/oil proof fastened the tube to the inside of the hull ; castor oil being very suitable; tends to buy the local pharmacy out of the oil!- the results have always been good, barring the one where I had a oil leak; the basic funcion being that it will work through the liquid and hull, but not through air- I'm sure someone will be along with a more technical answer; or explain to me why this will not work in a RIB, but it has saved drilling more holes in boats in the past.

[Hightower]

I know of a few people on RIBnet that have silkaflexed their transom mounted transducers into the hull. I would do a search as there are a few threads on the subject. What you don't want are air bubbles or pockets between the transducer and outer hull, this will stop the transducer from working.

[BruceB]

It is more the position that I am curious about. I understand the technicalities of how to mount them it is really just will the tranducer and outboard interfere with each other mounted as they are so close to each other.
Anybody got a transducer mounted in the well that works OK?

[Hightower]

I can't see why it would interfere any more in the well than sitting closer to the outboard on the transom! Unless you had an inboard, which your profile suggests you haven't got.

[jwalker]

Originally Posted by BruceB

It is more the position that I am curious about. I understand the technicalities of how to mount them it is really just will the tranducer and outboard interfere with each other mounted as they are so close to each other.
Anybody got a transducer mounted in the well that works OK?

Use your supplied Garmin transducer in the well using a big dod of silicon...without air bubbles. Chock it or tape it to keep it steady while the silicon cures.
On my destroyer, I mounted it slightly to the side because there is also a drain bung in the centre of the well. I originally used to make a resin wedge cast into the well with the transducer set into the top of it but it's unnecessary, the silicon does the job fine. I didn't/don't experience any turbulence problems.

[BruceB]

Cheers, thats what I was thinking and just wanted to be sure before putting it in or drilling any holes.
I would rather have it in the well than mounted on the transom where it is slightly more vulnerable and causes a minor amount of drag. That may be worth 0.000001 mpg!

[laser]

in our uni ribcraft 4.8, ribcraft mounted a through hull transducer in the well, so i cant see there being any issue there. We have never had any problems.

[limeydal]

Bruce,
I did what you are suggesting and have had good results so far
Photos below,

http://rib.net/forum/showthread.php?...ght=transducer
cheers Dal

[Cookee]

Don't worry turbulence from the prop doesn't go forwards except when you're going in reverse.

[BruceB]

I actually meant turbulence from an in hull transducer causing cavitation due to the disturbed water flow over the transducer being drawn through the prop.

[Cookee]

Originally Posted by BruceB

I actually meant turbulence from an in hull transducer causing cavitation due to the disturbed water flow over the transducer being drawn through the prop.

I see - I would go with the suggestions of mounting it inside the hull and not bother with making a hole - they usually work at least as well anyway! Whilst I have never used this method I have experience using sounders mounted like this and they work very well with no holes!

[ian parkes]

Just trying to sort out my own transducer . I got the transom mounted one as it can also be mounted in hull.

Its not an easy thing to know you have got it right having never fitted one before .
I tie wrapped it to a pole and held it over the side at slow speed so i knew what to expect as a baseline . Problem is mounting the thing temporarily on or in the boat to test it .
I like the silicone idea as its easy enough to peel it out again.
I was also told to stick it in a big dollop of vaseline to find the right place inside the hull ??

Two things Iam not sure about are
1 does the transom mount tranducer have to face as if it were mounted on the transom , because if I fitted it inside it would be better reversed and maybe screwed to the inside of the transom with the base set in silicone

2 At what speed can I expect the sounder to work at , obviously in calm water as i expect as soon as the boat starts bouncing off waves its pretty useless anyway

[wavelength]

we have siliconed them in all sortsa boats for years- fast fishing boats ribs etc. If you want to try it out beforehand just throw some water in the well, put the transducer where you fancy putting it and keep it in place with sommat or other. Bag of sand for instance. As long as you have the water in there it will sound thru the hull fine. One of our boats had the transducer thrown in the well all the time we had it, just needed to put a bit of water in there after launching. As we used it for beach launching the water was often in there, and everywhere else, automatically espec' near high water with a bit of a wind behind it.
We currently have a humber destroyer and an ocean pro with transducers siliconed in the well-both work fine even at speed.

[Simon B]

Is there a drop off in resolution when mountied through the hull? I supose this could also be tested if one ahd the patience and will!

Surely there's a degree student out there that needs a project?

[Nasher]

My in hull transducer works better at speed than the transom mount one did.

I can only assume its because the water is 'cleaner' passing over the planning pad than it is 3 or 4 inches behind the transom.

Nasher.

[Tony Hill]

Bruce
We internally mounted three transducers into the new SAMS RIB at Dunstaffnage. Signals breaks away at around 30 knots but at this speed its too late anyway. If you give us a ring or call in we can help you sort this and the A frame.

Tony

[BruceB]

Tony,
I got your message but thought it better to wait till after the holidays as there is no rush for everything, hull hasn't even started building yet and isn't due till march. All the electronics should have arrived by then so I will know exactly what has to be mounted on it.
Will be in contact after the new year.
Is that the new RIB they got about 4-5 years ago or another newer one?

[keelhauled]

In the rear well of the Valiant I siliconed the transducer over the keel. There must be voids or timber or something in there as I could not get any signal till I kept the transducer to the side where its perfect. I suppose what I'm saying is dont use anything as permanent as silkaflex till you test your unit.

[Pete7]

Since the boat hasn't been built yet send the tranducer to Humber and ask them to glass it into the hull before the deck goes on and feed the wire up somewhere sensible. There is little to go wrong with them and it would be well protected.

Pete