Backing Plates

[painkiller]

I'm thinking about adding additional padeyes to my boat for jacklines. I know I need to use backing plates on the padeyes to give them adequate strength for the job. The question is, how beefy do the backing plates need to be? Wichard sells ready-made backing plates that match the shape of their padeye bases. Are these sufficient? For some reason, I always thought of backing plates as covering more surface area than just the shape of the padeye itself. Maybe I've read too many sailing disaster stories.

Thanks!

[AjariBonten]

More is always better, IMHO; but I have no idea what would be a minimum.

I personally would not use a backing plate that is less than twice the area of the piece of hardware; but I have NO basis for that opinion, it just feels right.

[sailingdog]

Ajari—

The thickness and size of a backing plate really depends on what equipment you're backing and what the loads are going to be like.

[painkiller]

What do you recommend for jacklines, Dog, in terms of thickness and area?

Assuming that beefier backing plates are needed, is that something you can buy at a West Marine or is that typically custom fabrication?

[jrd22]

Theoretically, there is probably some formula for the size of backing plates based on the anticipated load. I've found that it usually depends on how much room you have in the location below what you are installing. Bigger is better, but I've never had anything rip out and some of the "backing plates" I've seen are nothing more than washers on the bolts so I don't think you need to get too carried away with them.

[AjariBonten]

Originally Posted by sailingdog

Ajari—

The thickness and size of a backing plate really depends on what equipment you're backing and what the loads are going to be like.

Naturally. The real question is, what sort of formula is applied? It's such a general question. A backing plate for shrouds (chainplates, essentially) certainly needs to be more robust than a backing plate for a hand-hold, for instance.

My comments were a gross generalization; and I thought I was fairly clear on that point.

OH, that last sentence sounded snippy or offended. I'm not in the least; but I can't think of a more concise way to say what I said.

[xort]

how much room you got?
are you using wood, aluminum or SS?
what is the construction of the deck? thin, cored deck will need more than a thick solid deck

[painkiller]

I'm planning on putting the padeyes on the vertical surface of the cockpit benches so that I can run jacklines along the full length of the cockpit. I have plenty of room for backing plates. The glass there is solid, but possibly thin. I hadn't ever considered using wood or aluminum, but that's probably not a bad idea.

[soulesailor]

I use IPE (wood) for my backing plates. It's strong as all get-out, doesn't rot and is way, way cheaper than teak.

[AjariBonten]

White Oak is good too.