Adjustable transom mounting board

Ovey · 13 January 2014, 22:09

Hi all, I have just bought a Raymarine MFD with transom mounted downvision transducer that I'm going to fit sometime soon.

Having seen the problems that people have had mounting transducers on the transom I did some Googling and found videos and photos of adjustable transom mounting boards, allowing you to play with the depths without drilling loads of holes in your transom, but I can't find anyone actually selling them despite searching here and elsewhere. I'd possibly be able to make one, but time is of a premium these days, and I'm sure it would look like a Blue Peter effort!

So, does anyone know where I could buy an adjustable mounting board?

Thanks!

jyasaki · 16 January 2014, 17:56

Get a piece of plywood, about 3-4 inches wide by a couple-three feet long, and temporarily mount the ducer to it; clamp the assembly to your boat. Big C-clamps will work fine, as will most large woodworking clamps. The wood should not extend beyond the hull line, but the transducer should (at least a bit.)

All you're trying to do is identify a position that works; you're not temporarily mounting it for months (hopefully.)

The normal starting configuration will be with the midline of the ducer even with the hull; move it up or down as required to get the performance you want at various speeds.

jky

captnjack · 16 January 2014, 18:14

Most transducer brackets actually have 1-2 cm of adjustability built into them. The Raymarine P66 transducer (I assume this is yours?) can move up and down a little, tilt up the sending unit at the hinge and you can readjust it if its too low or high.

Johnscubanut · 16 January 2014, 18:32

If possible & you have a solid hull with no air spaces, mount the transducer in the splash-well or similar area using epoxy resin. Done that on ours & it works a treat with no loss of signal at speed & if we happen to ground, no damage to the unit! Yay!

Ovey · 16 January 2014, 18:39

Thanks for the info. It's the CPT-100 transducer, specifically for the down vision system.

I'm not sure you get the full picture as clearly as the system can give if you mount it inside the hull but I can try with the water filled bag method if the transom mount doesn't go too well.

jyasaki · 18 January 2014, 20:07

Quote:

Originally Posted by captnjack

Most transducer brackets actually have 1-2 cm of adjustability built into them. The Raymarine P66 transducer (I assume this is yours?) can move up and down a little, tilt up the sending unit at the hinge and you can readjust it if its too low or high.

Yup, but that doesn't allow you to move side-to-side to find a location that doesn't get interference from chines, prop, and other turbulence-causing things.

jky

9D280 · 19 January 2014, 12:22

Once you have it positioned, stick a lump of real wood onto the transom with something like sikaflex and paint with epoxy paint to match the hull colour.

- no holes and if its anything like mine that 1/2" back means the 'ducer is positioned above hull line due to the water rising behind the transom. (potentially meaning slightly less chance of impact damage)

jyasaki · 21 January 2014, 16:14

On my boat, the aluminum hull has a 2" lip where the hull extends past the back of the motor pod. To mount the transducer, I took a scrap 2"x3" lump of UHMW, formed to fit reasonably well on the lip (the angle was something other than 90 degrees, and I had to take the lower edge off to accommodate the weld), then glued/screwed it in place (screws up through the lip, glued to the pod - no holes into dry areas.)

Did the same with a paddlewheel speed sensor, which, realistically, never gets used.

jky