Jack plates... aluminum or Okoume?

I have a pile of 1/2" Okoume and plenty of epoxy on hand.

Need to make the attached jack plates.

They slide in a set of rails attached to a vertical part of the hull, lowering the outboards into wells.

Outboards are Evinrude Etec 30's.

Could I and should I make these out of wood?? The rails are aluminum and already on site.

Wood/epoxy would be free, while I have to pay like $700 to make them from T6061 aluminum.

Any suggestions on wood or aluminum thickness? Which material to use?

I figure they need to be engineered to be like the transom of a power boat that can handle 30hp.

Thoughts?

 

Rails in place, are what, aluminium channel ? I guess that would dictate the thickness somewhat. Trouble with timber is it can swell or shrink according to moisture, which might cause jamming. It comes into my head to employ HDPE on the contact areas so it slides smoothly. How you mate that with your ply, is another matter.

 

Yes, rails are aluminum square tube, cut in half to make a pair of U channels that capture a sliding plate/board.

Was thinking about the wood expansion too. Thought maybe with enough epoxy it wouldn't be an issue. I can definitely bolt my HDPE in place for the slides. Not an issue.

Was mostly wondering if a wooden bracket would last a while... be strong enough for the 30hp outboard and how much half inch ply to use to take the force from the outboard.

 

So does okoume ply make sense?

 

How thick can the thing be so it still fits in the slot ?

 

A 30 HP outboard should have 1.5" of wooden mount, so how thick are the slots in those rails? You could squeak by with 1.25" if you didn't hammer it a lot.

 

Thanks, guys. That is the data I was trying to find. 1.5" for 30hp transom.

I'll check the slide slot, but it's 1.75" if i recall.