Pre Made Panels That Can Stand Up to Engines Pushing Them?

[Chotu]

I was thinking aluminum at first but don’t want to worry about metal.

Can someone name a very lightweight composite panel that I could use in place of 3/8” thick aluminum plating?

I will have bolts going through this and a backing plate if necessary. But it will be directly supporting all the weight and thrust of a 30hp outboard.

[Chotu]

To make it more simple/clear, what’s the lightest weight premade composite panel you’d make a transom out of that has an outboard motor bracket bolted to it?

[Chotu]

Was thinking coosa

[Cheechako]

So.... it's not an outboard bracket or Armstrong Bracket, it's replacing a transom?

[rslifkin]

Coosa should be strong enough, but I'm not sure if it's usable without glassing over it or something. G10 is out because you wouldn't be able to drill it safely. But some of the other non-epoxy fiberglass boards (with some paint) would work.



Is this going to be just a pad for the motor to clamp to, or is this going to be an actual transom piece (tabbed in place)?

[Chotu]

Originally Posted by Cheechako

So.... it's not an outboard bracket or Armstrong Bracket, it's replacing a transom?

It’s quite hard to explain.

It’s like replacing a transom for a 30hp motor. Yes.
That “transom” is on tracks to slide up and down dipping the outboard into the water or holding it free of the water.

[Chotu]

Originally Posted by rslifkin

Coosa should be strong enough, but I'm not sure if it's usable without glassing over it or something. G10 is out because you wouldn't be able to drill it safely. But some of the other non-epoxy fiberglass boards (with some paint) would work.



Is this going to be just a pad for the motor to clamp to, or is this going to be an actual transom piece (tabbed in place)?

Ahhhh. Damn. I was hoping coosa was stronger than that.

This is a “transom” that fits into a pair of 2” U channel aluminum tracks where the U’s are facing each other. So it slides up and down in the tracks to raise and lower the outboards.

The “transom” is about 18” wide and 3ft tall.

It WAS a an epoxy over wood piece with a mounting plate (also of wood) glassed on. That all rotted.

The wood just dragged along the track and worked pretty well without too much resistance.

Now, I’d like to use a thinner, but stronger material for the “transom” so I can add some PTFE or Delrin strips to the edges and have a nice slide.

I also want to add rubber bushings somewhere (maybe between the Delrin and the “transom”) to deaden the awful noise they used to make without vibration damping.

[Cheechako]

Originally Posted by Chotu

Ahhhh. Damn. I was hoping coosa was stronger than that.

This is a “transom” that fits into a pair of 2” U channel aluminum tracks where the U’s are facing each other. So it slides up and down in the tracks to raise and lower the outboards.

The “transom” is about 18” wide and 3ft tall.

It WAS a an epoxy over wood piece with a mounting plate (also of wood) glassed on. That all rotted.

The wood just dragged along the track and worked pretty well without too much resistance.

Now, I’d like to use a thinner, but stronger material for the “transom” so I can add some PTFE or Delrin strips to the edges and have a nice slide.

I also want to add rubber bushings somewhere (maybe between the Delrin and the “transom”) to deaden the awful noise they used to make without vibration damping.

A couple layers of 3/4" Starboard bolted together work? 1/2" aluminum in the center? total 2". Would slide with no additions. It's tough as heck.

[Chotu]

Originally Posted by Cheechako

A couple layers of 3/4" Starboard bolted together work? 1/2" aluminum in the center? total 2". Would slide with no additions. It's tough as heck.

I don’t know. That’s why am asking the question. I don’t know any of these premade composite panels. I made my boat from scratch. I have never used Coosa board or starboard. I know nothing about them.

Anyone care to say if the starboard will work?

I was originally thinking aluminum plate, but, I didn’t want to have to deal with all of the cosmetic issues that come along with that.

[Cheechako]

Originally Posted by Chotu

I don’t know. That’s why am asking the question. I don’t know any of these premade composite panels. I made my boat from scratch. I have never used Coosa board or starboard. I know nothing about them.

Anyone care to say if the starboard will work?

I was originally thinking aluminum plate, but, I didn’t want to have to deal with all of the cosmetic issues that come along with that.

Well, Starboard is a bit like Nylon. Tough and gummy when drilled. But hard enough to drill and tap fine. It's slick, so slides well, but maybe too slick to mount an outboard on to? You can't break it with a hammer.
I have used it on an outboard bracket that had the same issue as your big one.... rotted. It worked fine. But a small bracket.
It can bend though, ie: not as rigid as wood maybe?. I would think a 2" piece 18" wide would work. But 3/4 + 1/2 Alum + 3/4 should be fine.

Why is your bracket 3 ft tall? Or is the "transom" not that tall just the channels?

[svtrio]

I considered various replacements for the transom on my boat, which has a stillette sail drive mounted on it, and coupled to a Beta 30 hp diesel.

I used Coosa blue, laminated both sides with biaxial cloth. Bolt holes drilled over size and filled with epoxy. It doesn’t bend.

Starboard manufacturing folks were adamant that starboard is not suitable for structural applications, such as transoms.

I like your ideas about mounting the sliding transom.

[rslifkin]

What about just buying an inch thick sheet of non epoxy based fiberglass board and cutting to shape, then adding the sliders?

[Benz]

Originally Posted by Cheechako

A couple layers of 3/4" Starboard bolted together work? 1/2" aluminum in the center? total 2". Would slide with no additions. It's tough as heck.

My homemade outboard bracket is exactly this, only smaller: 1/4" aluminum plate sandwiched between 1/2" Starboard. I'd scale it up without any qualms.
It's worked perfect for 10+years.

[jimbunyard]

1" coosa 26, 3/16" glass on both sides, 5/16" UHMW sliders fore and aft on the edges with a 5/16" UHMW 'cheater' strip /aluminum plate matching the U channel thickness in the center to resist thrust (if needed).

[Chotu]

Originally Posted by rslifkin

What about just buying an inch thick sheet of non epoxy based fiberglass board and cutting to shape, then adding the sliders?

This sounds like a winner to me.

Inch thick polyester fiberglass board, 1/4” rubber mat for cushioning and sound damping along edges that make contact with the track, 1/4” thick Delrin or similar strips on top of the rubber mat strips, bolted into place.

Then reason out the part the outboard clamps to and bolt that on through the 1” thick piece of polyester/glass.