Rail Installation Question

[mthieme]

I have a 14' Mckee Craft which is similar in construction to a Boston Whaler...glass over a styrofoam core. The glass is relatively thin. The factory uses .090 aluminum underneath the glass where any fittings are mounted.
I have 6 stanchions for either side to run the rail through. I'm afraid regular screws might fail since the glass is so thin and foam definitely ain't gonna hold anything. Any suggestions? I was thinking maybe something like plastic sheetrock anchors that could bite into the foam and compress upwards towards the glass. Of course using a generous amount of some marine sealant in each hole. I'd hate to drill larger holes than necessary, but if I have no choice...
Is there a better way?
I anticipate a hard life for these rails (such as the kids leaning on them, pulling themselves up on them, mounting a bimini on them, etc.), so the sturdier the better.

 

[tashasdaddy]

Re: Rail Installation Question

marine toggle, possibly. thats what they mount pedestal seats with.

 

[mthieme]

Re: Rail Installation Question

That looks like it would work well.
Installation could be tricky since there's not a void underneath.
Getting them underneath the glass into the foam looks like it would very tricky. If I disturbed the foam too much, it could cause a void resulting in a weak spot too. This might not be a major factor (?).

Upon googling a little bit. Someone with a Whaler was doing a similar project.
He discovered quickly toggles were required for any kind of firm support.
He drilled a hole, bent a nail and put it in a drill to create a relief for the toggle. Got the toggle in and then back filled with resin. He didn't mention how he kept the resin out of the threaded hole in the toggle though...I'm thinking tape would be sufficient.

 

[mthieme]

Re: Rail Installation Question

Hanna passed through today. After the worst of it, I figured I go get the aluminum tubes at the local hardware store. 5 hardware stores later and no tubes...geez I hate to go to West Marine, they're gonna soak me me for sure.

 

[mthieme]

Re: Rail Installation Question

7th hardware store had two polished tubes - $29.95 each.
ouch.
Boat is back in the water as the weather has passed. So it will have to wait until the next drydocking.

 

[Uraijit]

Re: Rail Installation Question

I'd do something like how I had to do the repair on my swim deck.

Drill a hole, and " wallow" out a cavity in the foam (or in my case, rotted wood) as large as possible. Then take resin and fiberglass mat, and soak/stuff the mat into the opening until it's full. Let it set up, and drill a pilot hole in it. Then screw into the pilot hole...