Jim, I am assuming this was directed at me.
I agree with your three additional reasons for having a hatch
mechanism that can be closed from either inside or
out. To externally close the hatch on my boat, I
have to use an external clamp which is klutzy.
As to the need to have an overpressure release that is external, I
don't see the need. Actually what I installed on my boat for
overpressure is a pressure relief valve with a small cracking
pressure (<1 psi). My thinking was this would
automatically protect the boat from over pressurization. I
think a manual ball valve that the pilot routinely opens and closes as part
of NOP to equalize prior to opening a hatch would work fine as
well.
I really like Phil's design for hatch release mechanism for the
DeepWorker 2000. If you email me off line, I will send you a couple of
pics I took at the Vancouver Psub convention of the mechanism.
If ever get a chance to visit Phil's toy factory in Vancouver, you will
think you have died and gone to heaven.
Cliff
From: "JimToddPsub@aol.com"
<JimToddPsub@aol.com>
To:
personal_submersibles@psubs.org
Sent: Sun, January 2, 2011 9:26:57
AM
Subject: Re:
[PSUBS-MAILIST] Cliff's Hatch Closure Mechanism.
Phil,
Exterior emergency access is one reason this seems to
be advisable. Also:
1. The boat is in the water unoccupied and you want to
keep waves and wake from splashing in.
2. Towing it on a trailer down the highway in a rain
storm.
3. Keep insects from entering and setting up
housekeeping while not in use.
Would there be a need to have an over-pressure release
operable from the exterior also? Do you prefer a pressure release
that is manual or automatic or is it dual mode?
I've gone through a couple of different designs in my
mind, but really wanted to see yours when I'm in the San Antonio area.
Thanks for mentioning the Deepworker 2000. That's one more reason to
make an educational pilgrimage to Vancouver.
Jim
In a message dated 1/2/2011 8:33:58 A.M. Central Standard Time,
cliffordredus@sbcglobal.net writes:
Alan
These adjustable draw latches have worked fine on the R300. They
develop enough force to compress the hatch O-ring. The hatch seal
works fine. The seal does not leak. They do not have an
outside release mechanism other than removing the viewport retaining
ring that is held by a series of allen head bolts.
On my next boat, I will go with the hatch mechanism similiar to that
used on Deepworker 2000.
Cliff
From: Alan James
<alanjames@xtra.co.nz>
To:
personal_submersibles@psubs.org
Sent: Sun, January 2, 2011 12:50:20
AM
Subject: [PSUBS-MAILIST]
Cliff's Hatch Closure Mechanism.
Cliff, if you're about.
I noticed your hatch closure mechanism seems to
be a simple adjustable toggle latch.
I bought a few of these a while back thinking I
may use them.
How have they turned out? Do they exert enough
force? Are you getting any water in?
Also do you have any way of opening these from
the outside in an emergency,
or is the
"Big Hammer" the emergency opening device?
Regards Alan