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

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.

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

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?

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

Was thinking coosa

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

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

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

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)?

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

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.

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

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.

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

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.

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

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.

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

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?

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

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.

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

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

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

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.

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

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).

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

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.

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

Something like this product?
https://www.lbifiberglass.com/product/gpo1/

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

Indeed.
According to King Plastic:
“The King StarBoard® Family of Marine Grade Polymers are strong, but they are not a structural material. When using these products, they must be supported by a load bearing framework ...”
➥ https://www.kingplastic.com/support-techniques/

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

Ah, damn. It’s not easy to get those sheets right now and they’re like $500 a piece for the amount needed to create each motor mount.

Back to the drawing board.

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

Is it easier to design a new system or to change your attitude about cosmetic issues?

As I get older, and older, and older, I find I have much more tolerance for “cosmetic issues.” Both the boats and mine.

What I don’t want to give up on is a low maintenance solution. My time is my most valuable thing.

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

I think you are missing something in my posts. I am replacing these because they write it out. Not because they are the wrong color or texture. They fell apart.

So now I am also trying to do like you are saying and get something that works forever.

The aluminum sheet is also $1000. For 3/8 aluminum. So, I think it might be back to just building these out of composite. Because these are ridiculous prices.

My main concern building these out of composite is the tendency they will have to peel apart a cored laminate. So, I think I will make them in two parts. One part the flat panel that slides in the track, the second part the actual piece that the motor clamps onto. And I will through bolt them together. How does that sound?

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

Starting from scratch. These are the current slides.

Any Ideas on how to do these in the following way:

*no wood
*rubber bushings/mat to stop awful vibration noise
*Delrin/HDPE or similar at points of contact with the aluminum tracks.

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

For the rubber and delrin idea, I'd likely plan to use a somewhat soft rubber sandwiched by the delrin. Make it fit so that it's compressed slightly in the tracks, as that should keep there from being any play that would cause rattling.

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

I was thinking the same. Like a rubber mat material under the strips of Delrin.

The rest however... is getting tricky.

My through bolting self made composite idea really wasn’t a good one because there is very little space behind the slide. I had thought there was a little more clearance.


The tricky part in any material is joining it together to withstand the weight of the outboard, plus it’s full propulsion force.

These wooden ones withstood the forces but succumbed to rain.

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

What about making something with delrin rollers on the sides to fit into the track instead of sliders? That might let you change where the bolts, etc. have to go enough to make it fit.

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

Maybe! I had been relying on the sides of the large sliding piece of wood for lateral stability. Would rollers be able to support that pressure?

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

Think about the forces on an anchor roller. I see no reason a roller setup couldn't be built strong enough.

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

Exploring the idea of 1/2” aluminum plate a second, would I use aluminum L angle and through bolts to attach the rest of it to the big sliding plate?

L- angle won’t be 1/2”, so is that going to be a weak spot?

It’s tricky stuff.

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

There is no way that I’d rely on starboard, no matter how thick to support a 30hp outboard.

1. It’s slippery as hell, even tightly bolted to it the outboard will have a tendency to wander.

2. Starboard being an unsupported plastic tends to “creep” it undergoes plastic deformation that means it will change shape as pressure is applied to it. Not quickly, but still happens.

3. The manufacturer states it’s not a structural member.

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

Well now that we see what you're doing...

Don't over think it.

Half inch aluminum is your best bet, all bolted together with ss bolts.

Use inch and a half (or whatever your inner slide channel dimension is) black UHMW blocks for the 'bearings', routed or tablesawn out to fit the half inch plate, secured to the plate with countersunk ss bolts.

Use 3 or 4 inch channel for the standoff, again bolted to half inch plate to mount the motor on.

If you're worried about stiffness, bolt a piece of 1/4 X 2 X 2 angle across the bottom of the plate, or cut a piece of the UHMW bar to mount vertically in the center of the 'slider' plate to take the thrust (providing the hull is strong enough there; an aluminum angle mounted inside should provide plenty of stiffness if not...)

https://www.amazon.com/Black-UHMW-Po.../dp/B084H1JK7T
https://www.onlinemetals.com/en/buy/...dard/pid/14600

1/2 al plate 272.00

3/8 al plate (almost certainly sufficient) 227.00

https://www.midweststeelsupply.com/s...1aluminumplate

If you look around you'll probably be able to find the plastic and aluminum cheaper locally.

Black in the sketch is UHMW bar, grey is aluminum.

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

In that case aluminum is the best bet.

Try this place for aluminum, they will ship.

I just bought 10’ of 1-1/2” by 1/4” angle for under $30.

They will custom cut. Just buy what you need.

https://metals.shopjfi.com/?l=1

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

You’re right!

Thank you for bringing the aluminum back into focus.

I have been working through aluminum myself and it seems to be the way to go.

The big issue is those C channel stand-off pieces. The plate the outboard grabs on to in your drawing is parallel to the plate in the slide.

In real life the outboard looks like this, because transoms are angled on Jon boats and whatnot. Any ideas on how to do that channel standoff part with a large standoff and an angle?

I think I’m a little rusty figuring stuff out or my meds have me stupid.


The part the outboard grabs is at quite an angle and quite a stand off distance from the perfectly vertical slide to account for all the controls that come out of the front of an outboard.

So the sliding plate is perfectly vertical and the outboards grabbing plate is at the angle shown in this pic and about a foot from the sliding plate.

https://encrypted-tbn0.gstatic.com/i...3_gmg&usqp=CAU

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

Just wondering if you could mount a standard outboard mounting bracket. They make them for a 30 HP and some are electric assist. They even have a a bracket for mounting to a swim step. Lots of brands and models.
https://panthermarineproducts.com/ou...otor-brackets/

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

There should be some 'trim' adjustment that allows you to alter the angle of the motor.

If you need more 'standoff', and channel wide enough isn't available to accomodate it, and/or if the trim adjusment is insufficient, an angled channel' can be made with a couple of pieces of 2 x 2 x 1/4 inch angle and a piece of 3/8 plate cut to the needed dimension.

Of course a welder could also do the same thing with a slightly lighter weight, but more expense. And the possibility of broken welds.

Plus I like the modularity and ability to replace or change components without 'exotic' procedures like welding.

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

That's the thing.... the devil is always in the detail on these type of projects. It's easy to say "Starboard is not a structural material!" And yes, dont use it to build a full transom on a boat. Dont build a plank hull with it. Use it as a backing plate under a winch? Sure. ...... details, details.

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

Well, damn. You solved the whole thing.

What is it you are drawing these in? Fantastic illustrations.

I also agree very much with what you said. I prefer to book things together as well. It’s nice to be able to take them apart and fix them if need be. I think you may have solved the whole thing. Time for me to start ordering materials and getting to work. Thank you very much.

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

Glad to help, hope you get it worked out.

Sketches are done on the 'Paint' app supplied with Windows.

Also, though the angled plate shown in the second drawing is on the 'inside', for the most strength and rigidity, it should be on the outside, or, more accurately, depending on in whichever position you choose to mount the 2 X angles, the angled plate should butt right up against the slide plate and the engine mount plate...

Given what I know about the application, I'd mount the angle on the slide plate on the outside, and the angle on the engine plate on the inside.

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

What's wrong with drilling G10? I'm not trying to make a statement on whether it's strong enough to be a transom, but I have never heard it's unsafe to drill...how would you use it for anything then?

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

It’s safe to drill for most people…..but those with a severe allergic reaction to epoxy are unable to do anything with it.

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

It's fine for most of us to cut and drill, but G10 is epoxy based, so with Chotu's epoxy allergy, the dust would be a serious concern.

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

Oh, duh. Thanks :)