Mounting to the floor of my J16....

Don't drill and fasten into the sole. Doing so will allow water to penetrate into the underlying foam.
Better to fiberglass a couple of pressure treated cleats atop the cockpit sole and fasten to the them.

 

For just the cooler, thickness needs to be greater than the screw length used.
I'd want the grab rail through bolted, so I'd glass a stringer on edge,
so that I could fasten through it, side to side. Just remember to remove all the gelcoat
in the area where you'll be glassing the cleats in place. Resin won't bond to the finish gelcoat.

 

Screws will not hold a grab bar in place due to the torque loads.
It needs to be through bolted for safety. Either through the bar
or through side plates welded to the bar, like this...



By glassing a stringer to the deck on either side of the cooler
you create a vertical surface that will allow the through bolted mounting.

 

Do not use "pressure treated" anything on a boat... Fiberglass will not bond to it properly.. Use Clear Fir lumber or Fir Plywood encased in fiberglass cloth and mat.. Use a good marine sealant on your screws..

 

Ooops! :-[

Yeah, my bad. All I work with is epoxy anymore.
No problem getting bond to dry pt lumber with epoxy.
Polyester resin will separate from pt lumber, as stated above.

 

I would use foam blocks with SS lock nuts. Epoxy the nut inside the foam block then wrap the block in some bi-axle, then glass it to the floor.

Doing this will allow you to mount the grab bar, using SS bolts and its easy to remove if need be.

Wood will work as well, though.

 

What type of foam will resist those loads Creek? :-?

I ask 'cause I don't know... :-[

 

Brett a structural 36lb foam core will have the tensile strength and compression strength needed to support the load.

 

Thanks Creek, spent the evening reading up on the latest offerings from
the foam suppliers. Quite a variety of densities, compositions and shapes.
Still have a list of tech sites to work through explaining the application
and encapsulation techniques that need to be used.

 

I have a job coming that will be similar in application to the op. I will have 3 layers of foam, the bottom layer will be routed out about 1/4 deep where a SS plate will be installed, the SS nut will be welded to the SS plate to distribute the force better. Each layer will be individually then all wrapped together to form one solid block of the three layer, which will be glassed to the deck.

This will be the 2nd time doing a job like this and the 1st is still holding strong 2 years later.

 

Good work Creek. As always, Brett is researching like an NSA analyst. [smiley=1-computergeek.gif]

I'm assuming that using the structural foam is just more economical than a layered composite?

 

Yes he is and does, lol!

Not sure what you mean? The 36lb structural foam is a composite board. It is this same stuff used in Marine transoms, a lot of the SKA center consoles use it and high performance boats. It's avaiable in different sizes and thickness I buy it from a custom race boat builder it's a 1/2 thick so the 3 layers I use give me the 1.5" that need for the job I'm doing.

 

Yeah, sorry about that. I was thinking that the structural foam you were using was simply high density polystyrene, much like found in a Rubbermaid hand cart. Does it have an outer sheath on the board, with the foam core? All this is semantics anyways. I always think of composites as a layered or integrated product of two or more components.