[alberg30] Inspection Hatch / Deck Plate

[Rabbit649 at AOL.com]

From: Rabbit649 at AOL.com

dear Lee,
    I, too, have been planning the cockpit hatch job for when I can get the 
time and afford the aluminum hatch. In fact, I'm forced to do it, to correct 
a bad installation of an amateur 'inspection plate' installed by the previous 
owner when he hastily installed an Edson wheel by chopping (and believe me 
that's not too strong a word) through the cockpit sole.
    But I've always wondered about compromising strength. The boat, for all 
that it's overbuilt, still gets a great deal of its stiffness from the 
integrity of the deck mold as a whole (including the cockpit walls and sole). 
There is no question that any removal of material, any opening, especially a 
square one with small radius corners, weakens the boat. The books say "put 
back around the hole as much material as you remove" so 18" x 22" x 5/8" 
gives you the amount of material you removed, and then you have to design it 
into a lip which stiffens the opening. I've always thought the way to go is 
to cut a triangular cross section of foam and glue it around the opening 
underneath, then glass over heavily. Then you have a kind of sleeve around 
the opening for the full depth of the aluminum hatch frame, which is braced 
at a 45 degree angle up to the deck, with extra glass around the corners, 
where forces on the sole are likey to concentrate. Wish I could send a 
drawing. Can you visualize what I mean?
    What do you think?
Regards,
Paul
#23 Ashwagh

In a message dated 2/27/00 2:24:21 PM Eastern Standard Time, 
finnus505 at aol.com writes:

> From: finnus505 at aol.com
>  
>  Hi Guy,
>  I put a Bomar access panel in my cockpit sole to get access to my engine 
>  water pump, the stuffing box, and the cockpit scupper through hulls.
>  I bought the biggest one they make, I think it's about 18" x 22" if I 
>  remember correctly.  I got it through West Marine.  It cost about 60 
dollars.
> 
>  It is a plastic access hatch, and I was alitlle dissapointed when I felt 
it 
>  give a little more than I would have liked when I stood on it.  I could 
>  easily see someone going through it if they were jumping into the cockpit, 
>  either because they didnt know better, or what.  So I made a plywood cover 
>  for it, until I can make a nice strong teak cockpit grating.
>  There are aluminum access panels, or manhole covers, available, and though 
>  they run in the hundreds of dollars, oviously they are stronger, and 
require 
> 
>  no protection for themselves.  Hamilton Marine in Maine has a bunch in 
their 
> 
>  catalogue.
>  Cutting out the hole is no fun-the cockpit sole in the A30 is quite a 
>  laminate. On ours, 255, there were two layers of masonit core, sandwiched 
in 
> 
>  heavy glass laminates.  I used a sawsall to cut the opening.  The glass 
> dulls 
>  the blade quickly!!!
>  It's a very worthwhile project though.
>  Hope this helps,
>  Lee 
>  Stargazer #255

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