SailNet Community - View Single Post - Porthole Question
View Single Post
  #3  
Old 04-28-2007
sailingdog's Avatar
sailingdog sailingdog is offline
Telstar 28
 
Join Date: Mar 2006
Location: New England
Posts: 43,291
Thanks: 0
Thanked 11 Times in 11 Posts
Rep Power: 13
sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice
I would put the port glazing material on the outside... that way the material's tensile strength is part of what is holding the water out and the seal between the glazing and the hull only increases as the water pressure against it goes up. Having the glazing material on the interior of the hull is rather stupid IMHO... since any pressure against the glazing will tend to open voids in the seals around the glazing. Many new boats have dead lights that are panes of plexiglass or polycarbonate that are thrubolted to the cabin top.

When you're dealing with liquids under pressure, you always want to design it such that any increase in pressure aids the sealing systems, rather than weakens it.

IIRC, you should drill the holes slightly oversize as polycarbonate and plexiglass both expand and contract at a different rate from the fiberglass, so the bolts will move slightly relative to the glazing material.
__________________
Sailingdog

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

If you're new to the Sailnet Forums... please read this
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.

Still—DON'T READ THAT POST AGAIN.
Reply With Quote Share with Facebook