foreward looking sonar

[nik]

Hello, not having much boating experience myself, I would like to hear any opinions about hanging one of these jobbies off the back of a fast boat. Its a transducer for a foreward looking sonar unit. It is 51mm in diameter, and I presume it would usually be bolted into a hull.
Would It cause much drag? or are there some other undesirable side effects that could happen?

Thanks, nick.

[gtflash]

i tried a funky echopilot one.

i didnt want to drill a hole in the hull of my boat and have blocks to straighten the transducer out against the deadrise angle changing the shape of the hull (also hull very thick).

My added problem was the transduceres need clean water and my boat has a stepped hull. I tried to cheat and had a heavy gauge stainless bracket mounted on the transom. i took it for a five min spin from calshot to the esso jetty and back and it worked brilliant at displacement speed but planning the hull just jumbled its image. To top it all off the boat cavitated with any amount of trim and the stainless bent in half (only did 30mph). Ive still got it and still want to make it work but i would be very surprised if it didnt change a hulls dynamics. Echopilot put me in contact with a local fitter who didnt care what it did to my hull and told me he would only put it where he was told by me (so no help there).

Next season im gonna try putting it in a water filled bag and place it all round my hull to see if i can get a good picture from inside.

Hope its any help, any other ideas greatly appreciated also

[jwalker]

Can it look forward if it doesn't protrude below the hull?

[nik]

I dont think it will work at all unless it protrudes by its 37mm.
More info on:

http://www.echopilot.com/

I think its a great idea, but I suspect it will only work on slowish hulls. I did think about a system where you can drop the transducer once you slow down. But it would be nice to know if there is something in the water you could hit when at full tilt. (so you can avoid it of course)
Nick.

[gtflash]

i think you guys are probably right it wont work unless it protrudes below the hull but i got to give it a try cause i havent had many other ideas. One more problem with the through hull is when you trailer a boat. Bloody rollers everywhere!

[nik]

I have spoken to echopilot, and they say the active part of the transducer is on the sloping face. They say do fit them to fast boats, but it would seem to be trial and error as to how well it works at speed.
As for the roller problem, I think I would try to make a transom bracket that could be lifted when needed. It would have to be quite solid though.
Nick.

[gtflash]

speaking from experiemce. Very solid. I bent 15mm solid tube profesionally made @30odd mph. Make sure you bolt through hull.