Transom Question

[dolfundon]

I'm trying to mount a 10 hp. trolling motor<br />on my glastron boat. The transom does not go<br />all the way across the back of the boat. I<br />removed some of the flotation foam to expose<br />the fibreglass on the inside corner. I'm now<br />thinking I can put a good piece of hardwood<br />on the inside & the outside and bolt it all<br />together like a sandwich. Would that be a<br />ok way to do it ? Would it be strong enough?<br />I'm concerned about the strength of bolting<br />the motor (and the lift bracket) to only the<br />fibreglass. Thanks for any input.

 

[Pursuit2150]

Re: Transom Question

Go westmarine site they have outboard mounting brackets for kicker engines,designed for this application.

 

[dolfundon]

Re: Transom Question

Thanks for your response, but I already<br />bought the adjustable mounting bracket.<br />I'm trying to figure out the best way to<br />mount that. I have no transom in the area<br />that I need to mount the bracket. Thanks

 

[Pursuit2150]

Re: Transom Question

Go with the backing plates, the objective is to spread out the load as much as possible. I would consider St.Stl, or Alum. instead of wood.

 

[Terry H]

Re: Transom Question

Dol...I would sandwich with Aluminum, or Plywood...not solid wood for it will probably split. Plywood would need to be sealed with epoxy...100% sealed. Make the plates as large as possible to distribute the weight better...just a Thought

 

[Richard RG]

Re: Transom Question

Us 3/4" or 3/8" plywood, well sealed and glued together. Start out with a piece as large as posible, then reduce it by about thirty percent, finally add a piece slightly larger than the absolute minimum needed to mount the motor. This staggering of sizes will reduce hard points that my lead to stress failure at the edges. finally cover the assembly with fiberglass mat and a polyester resin. <br />Richard RG

 

[dolfundon]

Re: Transom Question

Thank you, Pursuit2150, Thought101, and<br />Richard RG, your input is great. Don

 

[SCO]

Re: Transom Question

I have a glastron, and want to do the same thing. Was thinking of having a plywood piece bolted flush and overlapping the transom piece (on the inside of the boat) and extending past the transom to the outboard portion all the way flush to the side of the boat. Then you could seal around the board where it extends past the transom and fill the gap with epoxy or cut wood pieces to fill the gap and glue it all together.This way you can tie the mount to the transom and also transmit the load to the corner and the side of the boat. Dont think i will do it on my model because the glass that extends past the edge of the transom to the side is too sculpted and I can get away with a lighter mount cause Im using a 3.5 hp motor.

 

[dolfundon]

Re: Transom Question

I put one inch plywood on the inside. It's<br />not a flat surface, so I layed in a bed of<br />good silicone to fill the gaps. I tied in<br />the edges with epoxy and fibreglass cloth, to<br />bond it to the corner. I'm now in the <br />process of shaping a piece of two inch thick<br />Teak wood, to fit the outside, as it's not<br />a flat surface either. I will then bolt it<br />all together, and mount the motor bracket.<br />I hope it works out. I have had some good<br />advice on this forum. Thanks SCO for your<br />input. Don

 

[SCO]

Re: Transom Question

Sounds good, but am worried about the silicone if I am reading this right. Once you bolt up from inside to outside are you going to be squeezing a silicone sandwich?

 

[SCO]

Re: Transom Question

Might well be a good solution, distributing the load and damping vibration. Might have to see it to understand it. My specific concern though is that the outside fiberglass may be allowed to vibrate and flex if it is not soundly bolted to the inside support which in turn ties the outside mount to the transom and side/corner of the hull.

 

[dolfundon]

Re: Transom Question

I didn't think of the silicone causing a<br />vibration problem. I was concerned with<br />filling the void only. Do you really think<br />it will cause a problem ? It would be very<br />difficult to change at this point.

 

[Pursuit2150]

Re: Transom Question

I don't think you will have a vibration problem, as it seems that you are making the mounting boards as part of the boat. Be sure you use large dia. washers to spread out the load surface.

 

[SCO]

Re: Transom Question

When finished are you going to be comfortable cranking down on the through bolts or will it stress the glass? If you will be afraid to crank down then you might consider a redo and fill the voids w epoxy,...or not. My comment is to point out a potential problem so you can rule it in or out. I cant see what you have done so I dont have an opinion about the soundness of the mount.