Transducer placement question

[Flyguy]

I have a Raymarine Dragonfly which comes with a huge (8" long - oh err) transom transducer. Raymarine recommend that this is mounted so that it just skims the water without interference/bubbles from the hull/prop etc. However as I'm putting this on my Zodiac FR340 the transom bounces all over the place even at anchor. So I'm thinking that mounting it so that it is submerged an inch or 2 under water would be best? Any reason why I shouldn't?
Thanks

[jyasaki]

Yes. The reason is it may not work very well, which is why they recommend otherwise. There's a possibility of the arm that's used to mount it causing interference (causing bubbles under the ducer.)

Dunno; best thing to do would be to mount it to a board or similar which you can clamp to the transom and experiment with different depths and locations.

jky

[Flyguy]

Thanks. That makes sense.

[9D280]

+1 for the clamp.

I took 3 goes to mount my 'ducer, and it ended up a good 1.5" above where the book of words hinted I should start!

[porkpiehat]

Sorry to 'jack this post but it seems like the perfect spot for my similar question...

I bought a Lowrance Mark 4 pro and bought a suction cup transom mount. I've tried various positions on the transom and angles, not to mention setting on the unit itself.

I've never achieved full fish archs, or it's loaded with surface clutter. I'm not sure if the unit is no good, if I'm placing it wrong, or if the the hull just isn't conducive to this. It's only 13 feet so it's hard to get the transducer far from the engine, plus there is a lot of drag on the fiberglass and pontoons from various patchwork.

anyone have advice or should I just return the unit and catch fish the old fashioned way?

thanks!

[freespirit3]

Just make sure you keep it out of the hull chine lines to the prop, I did this once many years ago and caused me havoc with cavitation.

Nearly bought a new prop it was that bad, retraced my steps from previous years holiday and use, moved the transducer and voila the boat was ok.

Only worked at slow speed but it was a good compromise.