Raising Through-the-Deck Sites

[Foswick]

I first read of the idea of raising the slot for through-the-deck chainplates years ago. I'm sure I've seen this, but now that I'm looking for it, I can't find anyone who has it.

Sometime in the next few years I will be repainting my deck. So, I'm starting to think ahead about this upgrade.

If you don't know what I'm talking about, it just involves laying up several small squares/rectangles of glass at the site where the hardware mounts, and tapering the edges of this raised "bump" for a smooth transition. The idea is to slightly raise the site of the holes so that water does not tend to pool at the site. It also adds some strength ... though not much.

Has anyone done this, personally or seen it done? I am comfortable working with fiberglass, but am wondering if there is a slick tip for making smooth transitions without a ton of sanding/filling. Just peel ply?

[coopec43]

There was a thread just recently. Maybe how to mount stanchions (I'll see if I can find it)

Guess what? I started it back in 2022!

https://www.cruisersforum.com/forums/f55/mounting-stanchions-267569.html

[GordMay]

Good Old Boat magazine (Issue 65, March/April 2009*) had an excellent article on curing chainplate deck penetration leaks, entitled “Chainplate Islands”.
Written by Don Casey, author of “This Old Boat”, the author addresses one of my pet peeves with boat builders. They install chainplates through the deck, without casting in a “houskeeping pad”. He details a simple way to remedy this failure.
The method could be adapted to remedy similar situations at any deck mounted hardware such as cleats & sampson posts, winches & windlass’, & etc.

* “Chainplate Islands” ~ by Don Casey
Pages 41 & 42 ➥ https://goodoldboat.com/wp-content/u...gob65mar09.pdf

See also:

➥ http://www.tartan37.com/T37TRC2S3.pdf

➥ Magic #16: Chainplate Islands

➥ https://www.cruisersforum.com/forums...nds-60727.html

[Foswick]

That's a really useful discussion. Thank you! I hadn't actually considered prefabricating the pads. I think I might still glass them in place to try to give them a very integrated appearance. I don't know, maybe not.

You mention that you wedged them, where necessary. Why would this be necessary? Wouldn't you want the tops of all the pads to be parallel to the deck they are mounted to? Or, do you have some cases, like under a pulpit, where the bases don't quite want to lay flat?

[RaymondR]

Lazer cut large SS washers. Put a thick rubber gasket under them amd screw them down to compress the rubber washers for a seal.

[coopec43]

Originally Posted by Foswick

That's a really useful discussion. Thank you! I hadn't actually considered prefabricating the pads. I think I might still glass them in place to try to give them a very integrated appearance. I don't know, maybe not.

You mention that you wedged them, where necessary. Why would this be necessary? Wouldn't you want the tops of all the pads to be parallel to the deck they are mounted to? Or, do you have some cases, like under a pulpit, where the bases don't quite want to lay flat?

The curve of the deck is not constant along the length of the yacht. If you don't compensate for that some stanchions will be vertical while others (the front ones) will be 20° from vertical

[Bowdrie]

Methods can change depending upon tools available.
If wanting to do your own laminations, I've found it easier to lay-up a big rectangle between a couple pieces of thick plywood that have plastic wrapped around them, a few C-clamps, (don't winch down too much,) and now you have your own piece of faux G-10 that you can cut several parts out of.
Yes, prefab is much easier than trying to do lay-ups on the deck.
Or one can simply get a piece of G-10 and saw out the pieces.
Round-overs on top edge and rounded corners for some class.
Some thickness is nice, I like ~1/4" minimum, 3/8" is nice.
If doing your own laminations you might be surprised at how much product/material it takes to get some real thickness.

[Iron E]

Everything mounted to our deck is raised by about 1/4"... Cleats, Stanchions, Tracks...etc.

If I were to do the same for Chainplates, I would get a sheet of 5mm G10, cut it to size, including the slot, bevel the edge to match the rest of the raised deck mounts, epoxy to the deck, and paint.