flush mount transducer

[dockdave]

Besides building a quick mica mold are there any other techniques for flush mounting a thru hull transducer.I originally had a fairing block, at 50 knots would push starboard bow down. Got rid of said block, lost the lean. Now i figure if 1 1/2" of underwater disturbance rid the boat of the leans at speed, if i suck all but the outboard edge of the transducer into the hull i should be good for another knot or 2. Any thoughts?

[DesperateDan]

what is the hull material??

if it is GRP/plastic or similar you can mount the transducer inside an oil filled tube on the inside of the hull and have no thu hull fitting at all. The sound waves will pass thru without problem.

Airmar make a transducer kit with an adjustable tube.

http://airmartechnology.com/airmar20...=All&PageNo=59

Dan

[Meanz Beanz]

Yes if solid glass and no core material a wet box is a good idea, I have even seen people mounting them on a bog/filler platform. I think that a wet box is probably the better option.

[dockdave]

boat is glass, got a peek at licquid filled ducer. sucks that i didn't see it before. thanks for the info, but the miser in me will not let me drop coin on another duplicate boat part. you should see my shed. I will definately remember it for my next project, for now i'll be glassin upside down FUN FUN FUN. thanxs again for your time

[dockdave]

meanz beanz
Is a "bog/filler platform" a butt load of glass that you then have to try and router up-side down? If so,rather drip some hot sticky resin on my face. I concure, wet box it is. Thanxs for your time.

[Roly]

Greetings guys, hope you don't mind another question.(Its related)
Like Dave I already have a transducer Airmar 520st-MSDF.
I have rebuilt my hull, wood strip glassed b.s. (840gm/epoxy)
I am pretty close to fitting my 'ducer and and reading this are having second thought about method.
I was going to rout the wood down to the outside glass layer,feather the timber edge & build up to 10mm+ of glass inside then holesaw to my 'ducer neck diameter.


That still gives me the drag of the base & having to make a fairing block.
As it is speed as well (paddle wheel), perhaps I can rout out to the shape of the base & then build a solid glass structural support inside the boat?
The project is majorly over budget so I don't want to buy another 'ducer.
Any thoughts?
What is the wetbox concept?

[Meanz Beanz]

Dave,

If you have the boat in the water you can sit the transducer on a melted freezer bag (those blue things) and place it on the site you want to use just to make sure it works and there is no air in the hull at that point for what ever reason. Not sure about the upside down thing.... is the Hull inverted at the moment?

Roly,

If you can get a section of hull as solid GRP in a sound fashion then yeah a wet box is an option. Most of the ones I have seen are made of plastic plumbing pipe and a cap. The pipe is contoured to the hull so that it sits at 90 degrees and stuck to the hull with Sika or epoxy (I think I would use Sika). Like Dan said they are filled with some viscous liquid and the transducer mounted through the top at about the mid point give or take. Then all you do is set the keel offset accordingly... no holes, easy to remove for repair/replace, no drag, set a 90 degrees, it really is the best way IMO. If you where building you could replace a section of core to allow for it.

That's about all I know...

Cheers
MBz

Edit: A plastic bag full of water (no air) would be fine for testing as well.

[dockdave]

MBz,
Guess i misunderstood your wet box. thought you were refering to a mold of exterior ducer dimension, glassed to interior of hull. (that being the upside down thing)
so, if i now understand you believe i can shoot through the hull with a viscous medium sandwich. (what medium would you recomend?) Seems to easy. I've recentely seen some Contenders with a pad of glass inside hull which someone then (i believe) cut the recess then installed ducer. I really appreciate your time and knowledge.
Thanxs,
Dave

[Meanz Beanz]

Dave,

Yes absolutely you end up shooting through the hull, no real point in all the mess around otherwise. Just do the trick of sitting the transducer on a bag of liquid first to make sure it works before you go to any effort, try a few spots, normally its solid glass near the center line and avoid anything that creates air/turbulence. So say we have a planing hull with an inboard you'd want to be as far back as possible, to the side of the skeg but in front of all the running gear so that it has the best chance of working at speed. If you have a glass hull you should only need to stick the box/pipe to the inside of the hull, no cutting required. The liquid can be anything non-corrosive and viscous, thick enough that hull pounding will not shake air into it. I have heard of oil or undiluted radiator coolant (Gycol) being used you may know of something else that will suit.

Clearer?

Cheers
MBz

Edit:Air is the enemy here, oh yeah and bloody great things like keels

[Meanz Beanz]

Looks like this guy has done it in silicone, a bit extreme for me but?

[dockdave]

MBz,
The company who builds that production model will be p.o'd if they read these posts. I still have to glass upside down to fill hole of old ducer mount, i gotta do this (wet box)cuz i can and it's fn cool. Thanxs again. Ol lady gonna be mad i'm going to ditz in barn on a school night. All goes well i'll be poppin the boat in AM.

any other cool tricks?
Thanxs,
DOCKSIDE DAVE

[Meanz Beanz]

Glycerine that's the other stuff they use... doh, took a little time to remember!

[Meanz Beanz]

[Meanz Beanz]

Clear polycarbonate lid is probably a better choice as a tank top if you go the above route.

[tom28571]

Originally Posted by Roly

Greetings guys, hope you don't mind another question.(Its related)
Like Dave I already have a transducer Airmar 520st-MSDF.
I have rebuilt my hull, wood strip glassed b.s. (840gm/epoxy)
I am pretty close to fitting my 'ducer and and reading this are having second thought about method.
I was going to rout the wood down to the outside glass layer,feather the timber edge & build up to 10mm+ of glass inside then holesaw to my 'ducer neck diameter.


That still gives me the drag of the base & having to make a fairing block.
As it is speed as well (paddle wheel), perhaps I can rout out to the shape of the base & then build a solid glass structural support inside the boat?
The project is majorly over budget so I don't want to buy another 'ducer.
Any thoughts?
What is the wetbox concept?

These ideas will work but are not the only, or even the easiest way, to mount a transducer. In a wooden boat, I cut a hole with a holesaw, bevel the edges and lay up with glass and epoxy. make a dummy of the transducer and cover with plastic tape. Set the dummy in a lump of thickened epoxy over the hole so it is as level as needed. After cure, remove the dummy and glue the real transducer in the recess with silicone. Works fine with no turbulence and it can be removed if necessary.

On a glass hull, just clean off the inside of the hull and go from the lump of thickened epoxy.

Most depth sounders come with a transom mount transducer and you need to buy the through hull if you want to that. These methods will allow the transom transducer to work inside to save some bucks.