High density polyethylene sheet

B

bluegene

New member
I have a Garelick cockpit ladder to install on my '87 cruiser. The best fit is to mount on the inside of the hull, underneath the gunnel - I plan to put the mounting brackets on port and starboard sides and move the ladder back and forth as needed. I want to fasten 3/4" polyethylene, cut to 1x4 size, to the hull, underneath the gunnel, using 3M 4200 sealant. The brackets will be installed on the polyethylene 1x4 with stainless steel screws. The purpose of the polyethylene is to provide a strong mounting medium which will hold the screws without going through to the outside of the hull.

Does anybody see a problem with this or have a better idea? I haven't found anything on incapatiblity of the 4200 [polyurethane] and polyethylene.
 
bluegene":2wxo8rm7 said:
Does anybody see a problem with this or have a better idea? I haven't found anything on incapatiblity of the 4200 [polyurethane] and polyethylene.
Click to expand...

As a data point: HDPE (like Starboard™) does not "take" sealants well at all. Also, it tends to creep under load. If you can accept these factors in your installation, then it should work.

I might tend to use pre-formed FRP (fiberglass board), but then HDPE is easy to work and it may not matter for a ladder installation in an open cockpit (where a leak or slight creepage wouldn't be a disaster). The ladder on my swim platform came with HDPE backing blocks, and when I reinstalled it I didn't change them. That said, since I overdrilled/filled/re-drilled the holes in the (cored) platform, I wasn't trying to seal anything in the way of the HDPE (it's like the bottom "washer" in the system; I did bed the top plates which are stainless steel) and thus didn't need sealant to stick to the HDPE. You may have a similar situation.

In contrast, I wouldn't use the HDPE for something like the "pedestal" block on a windlass (i.e the block between the windlass and the deck) because I would want to bed/seal it and I would not want creep.

Sunbeam
 
I had that ladder on a '95 cruiser and just screwed it to the inside of the coaming, not the hull. But it was a three step ladder. Sounds like you've got a two step?

Charlie
 
Thanks for the responses.

Sunbeam: I suspected the 4200 sealant might not like the polyethylene. So thanks, I haven't ordered the polyethylene yet. The FRP I found online was expensive. I'll go with some hardwood 1x4 instead and paint it after the sealant has cured. The 4200 doesn't like epoxy paint either. And, it's fairly protected underneath that coaming.

Cap'n Cat: That's what I was planning to do, except the coaming [if that's the word] doesn't extend quite far enough for my two step to reach. Also, attaching to the hull snugs the ladder farther into the side of the boat giving a few more inches of room in the cockpit.
 
Bill K: That's exactly the ladder I have. Very clean installation and simpler than my plan. I'll need to extend down as you did because the ladder is not quite high enough. Also, mine does not have the shelf underneath the gunnel.
 
Back
Top