Bulkhead Strength

newportknots · #1 (**permalink**) 03-20-2009

Hi there,

The chain plates on my New York 36 are currently bolted to a 3 inch thick fiberglass bulkhead. I'm considering mounting a diaphragm pump for head discharge behind the head using this bulkhead as a mounting location. The positioning of the pump would be 5 inches away from where the chain plate is attached.

When the chain plate is under load, would the bulkhead's strength be compromised by having holes drilled into it?

Mike

celenoglu · #2 (**permalink**) 03-20-2009

The distance is not too much, you can expect negative effects. This will not occur immediately but will cause deformations during time. It will be a better idea to add some epoxy and fiberglass as a base for your pump. This way you will not drill the boat but only drill the added on epoxy - glass.

sailingdog · #3 (**permalink**) 03-20-2009

The bulkhead is THREE INCHES THICK. These holes will be relatively small, say under 1/4" in diameter. Drilling the four holes you'd need to mount the diaphragm pump shouldn't weaken the bulkhead significantly, especially if it is THREE INCHES THICK.

If you're really worried about it... epoxy a block of teak to the bulkhead and use screws to hold the pump to the block of teak.

Quote:

Originally Posted by newportknots

Hi there,

The chain plates on my New York 36 are currently bolted to a 3 inch thick fiberglass bulkhead. I'm considering mounting a diaphragm pump for head discharge behind the head using this bulkhead as a mounting location. The positioning of the pump would be 5 inches away from where the chain plate is attached.

When the chain plate is under load, would the bulkhead's strength be compromised by having holes drilled into it?

Mike

newportknots · #4 (**permalink**) 03-20-2009

Thanks Dog and cenegolu.

I'll tell you what worried me: A PO had already drilled a 1" whole in the bulkhead to run an intake hose. With the amount of stress exerted on that bulkhead over time - I figured cracking was inevitable.

Dog - would I be wise to fill the old hole with thickened epoxy to restore some integrity at that point?

sailingdog · #5 (**permalink**) 03-20-2009

Quote:

Originally Posted by newportknots

Dog - would I be wise to fill the old hole with thickened epoxy to restore some integrity at that point?

Yes, and adding a couple of layers of glass over each side wouldn't hurt either.