Backing plates for mounting wakeboard tower--is plastic better than plywood?

[cheburashka]

I'm mounting a Joystick Pro wakeboard tower to my '97 Maxum 1900 bowrider. I've read a few good articles that mention using oversized pieces of 1/2" plywood behind the hull to spread out the stress to a larger area and prevent fractures. I can't get 1/2" marine plywood here, and I really don't want to buy a full sheet of outdoor-rated plywood just to make four 5x10 supports.

I read a post from someone on another forum who was thinking of using kitchen cutting boards--a slightly flexible and completely waterproof plastic. I guess "Trex" would be about the same. I'm thinking about using 1/2" thick plastic, liberally coated on the contact side with Bondo-glass to fill in voids left by the curvature of the hull, and clamped in place with the hardware that came with the wakeboard tower.

Anyone see any potential problems with this plan?

Thanks

 

[oldjeep]

Re: Backing plates for mounting wakeboard tower--is plastic better than plywood?

You can just use regular plywood. Should be able to buy 1/4 or 1/8 sheets at any home depot.

But there shouldn't be an issue using just about anything else - my backing plates are aluminum.

 

[cheburashka]

Re: Backing plates for mounting wakeboard tower--is plastic better than plywood?

OK. I'll use plywood.

Another question--I'm looking at the spot where the plate sits on the outside of the hull and if I put it parallel to the waterline, it rocks about 1/8". If I mount it at an angle, it doesn't rock but there are voids. Is there a way to fill in the area behind the front plate so that it matches the curve of the hull, or is this not a big deal?

 

[oldjeep]

Re: Backing plates for mounting wakeboard tower--is plastic better than plywood?

It should fit flat enough for the rubber gasket behind the plate to fit the contour. Your Maxim hull should be very similiar to my bayliner 195 classic so I suspect that you are putting the mount in the wrong place.

 

[cheburashka]

Re: Backing plates for mounting wakeboard tower--is plastic better than plywood?

I've got the front mount around 4" behind the horn grille on the starboard side. Any further back and I can't mount the rear mounts far enough back due to glassed-in intake boxes.

 

[oldjeep]

Re: Backing plates for mounting wakeboard tower--is plastic better than plywood?

I've got the front mount around 4" behind the horn grille on the starboard side. Any further back and I can't mount the rear mounts far enough back due to glassed-in intake boxes.

Behind the horn grill? Where is that in relation to the front of the windsheild. If your grill is the same place that mine is, that is pretty far back.

For reference, this is how mine is mounted - you can see the horn grill behind the front mount.

 

[cheburashka]

Re: Backing plates for mounting wakeboard tower--is plastic better than plywood?

Very different hull designs. Also, different tower designs. My side windows look to be a couple of feet longer than yours.

I'm almost done with the mounting. I'll post a picture when I get it all done.