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Jim:
The DeepWorker uses two different entry hatch closures - since it is
supplied with either a a titanium crash and lifting frame - or an aluminum crash
frame and lifting by the welded hull lug/eyes. The hull lift option is
always there - but a number of commercial users (including ourselves) prefer to
use a docking cursor on the A frame or lifting boom. We use a jet aircraft tire
in conjunction with the docking cursor which the sub dome and lift frame
snugs into - the sub can swing a limited amount for and aft, but can't swing
sideways. The T1 closure latch can be operated externally, but requires a small
open-end wrench. We also have a spiral-channel closure knob system which we used
on the shallow DeepWorkers in the 90's - it may be more suitable for a
home-build since requires only a small diameter (3/8th or 1/2") thru-hull shaft
and can be operated internally and externally. Essentially, the underside of the
large (3") fluted closure knob has a machined channel which spirals towards the
center and is open at one edge of the knob, a 'peg' attached to either the hatch
ring or hull ring exterior enters the channel as the hatch is closed - as the
knob is turned, the spiral channel draws the 'peg' and the knob tightly
together. Hard to explain, but you'd 'get it' in a second if you saw it.
We don't have a problem opening against high or low internal pressures 'cuz
we don't have any. We use a 1/4 pound cracking pressure, non-return automatic
vent valve that has a 3,000 psi working pressure and which also serves as
our vacuum port. We never dive any of our subs unless they've held vacuum for
several minutes immediately prior to launch - this procedure tests and 'sets'
the o rings and avoids a nasty surprise at the end of a large air-gap
launch!
Phil
----- Original Message -----
Sent: Sunday, January 02, 2011 7:26
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
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