Transom thickness

[JayMyk]

First time poster here.

I have a 1996 Fourwinns Horizon 170. I’m building a swim platform for it, and have the hardware ready, but when I look from the inside, I can’t see the very back of the boat. Does anyone know how thick the transom is? I read somewhere there’s 1” of gelcoat then Fiberglass. I assume the area around the leg would be thicker,am I wrong? Is there wood in the transom to screw mounting brackets to? I was planning on putting either a treated wood plate or an aluminum plate to bolt to but there is a ‘ 1/2 wall’ of sorts that hoses wires etc are attached to that doesn’t allow me access to the very back.

Pics are of one I’ve built, and a second I’m working on

I’m searching google and can’t find that information I’m actually considering building some platforms as a business, but gotta be able to attach properly!

Input is appreciated!

 

[alldodge]

The transom thickness is between 2 and 2 1/4 inch where the transom assembly mounts

That said the way your boat is designed where only the middle of the transom is that thick. I doubt the sides are the same. There probably not much more then 3/4. I would use aluminum or stainless plates to hold

 

[Scott Danforth]

First time poster here.

I read somewhere there’s 1” of gelcoat then Fiberglass. I assume the area around the leg would be thicker,am I wrong? Is there wood in the transom to screw mounting brackets to? I was planning on putting either a treated wood plate or an aluminum plate to bolt to but there is a ‘ 1/2 wall’ of sorts that hoses wires etc are attached to that doesn’t allow me access to the very back.

at most there is .03" of gel, then about 1/4-3/8" fiberglass, then the transom wood, then about 3/16-1/4" of fiberglass on the inside this is within the 2.0-2.25" dimension that AD posted.

agreed, on the sides where your hull bulbs out, probably mostly balsa or other core material there

you will need backing plates on the inside. so you will need to remove what is inside the boat preventing you from getting to the inside of the transom.

you cant just screw it to the exterior of the transom. you will need to thru-bolt to something substantial

I’m searching google and can’t find that information I’m actually considering building some platforms as a business, but gotta be able to attach properly!

good luck. to build these to sell as a business, you will need to have liability insurance. you also have to design the platform to be able to support 85lbs per square foot with a factor of safety over 2.0:1 and will have to test each one in a certified lab

depending on how heavy your platforms are, you may have to re-do buoyancy tests as well as add exhaust risers to the elbows

you may want to look into the ABYC standards you would have to meet.