[PSUBS-MAILIST] Idea..?

via Personal_Submersibles personal_submersibles at psubs.org
Thu Jun 18 14:53:15 EDT 2015


Brian, it also has to do with cracking pressure.  When  you surface the sub 
might be slightly over pressure but not with enough  differential to open 
the valve automatically.  That's when you open it  manually.  That would also 
equalize pressure if you have negative pressure  in the sub to make it a 
whole lot easier to open the hatch.
Jim  
 
 
In a message dated 6/18/2015 1:40:32 P.M. Central Daylight Time,  
personal_submersibles at psubs.org writes:

It is nothing but a T shape sealed by a spring. If internal  pressure 
builds up, it pushes the spring and the valve opens. So it is a  normally closed 
valve... but I suppose you could say its "open all the time"  in the sense 
that anytime pressure builds up, it will open.

On Thu, Jun 18, 2015 at 2:35 PM, Brian Cox via  Personal_Submersibles 
<_personal_submersibles at psubs.org_ (mailto:personal_submersibles at psubs.org) > 
wrote:


Couldn't you, theoretically,  have that valve open to the outside  all the 
time?   
 
Brian 

--- _personal_submersibles at psubs.org_ 
(mailto:personal_submersibles at psubs.org)  wrote:

From: Alec  Smyth via Personal_Submersibles 
<_personal_submersibles at psubs.org_ (mailto:personal_submersibles at psubs.org) >
To: Personal  Submersibles General Discussion 
<_personal_submersibles at psubs.org_ (mailto:personal_submersibles at psubs.org) >
Subject: Re:  [PSUBS-MAILIST] Idea..?
Date: Thu, 18 Jun 2015 12:15:57  -0400



 
I think most have an OP valve, and I'd strongly encourage any  who don't to 
put one in. If you read Kittredge's book, the lack of an OP  valve was the 
cause of the only K-boat accident so far. Fortunately nothing  happened to 
him, but Kittredge had a slow cabin air leak during his dive and  upon 
surfacing blew out the dome when just below the surface. He was blown  out himself 
with it. The sub sank, and he proceeded to re-float it without  losing  
beat. I use the OP valve routinely to equalize pressure so I  can open the 
hatch easily. Just a little push on the stem does it. One thing  about OP 
valves, they have to be capable of handling large flow rates. Don't  use a little 
Swagelok check valve or such small thing.  


Best,

Alec







On Thu, Jun 18, 2015 at 10:55 AM, Brian Cox via Personal_Submersibles  
<_personal_submersibles at psubs.org_ (mailto:personal_submersibles at psubs.org) > 
wrote:

Also  Alec,   I noticed your check valve overpressure valve in the  photo 
section.  That seems like a great solution to the  problem!   I guess I was 
not aware of that, does everybody have  one of those?


Brian

--- _personal_submersibles at psubs.org_ 
(mailto:personal_submersibles at psubs.org)  wrote:

From: hank  pronk via Personal_Submersibles 
<_personal_submersibles at psubs.org_ (mailto:personal_submersibles at psubs.org) >
To:  Personal Submersibles General Discussion 
<_personal_submersibles at psubs.org_ (mailto:personal_submersibles at psubs.org) >
Subject: Re:  [PSUBS-MAILIST] Idea..?
Date: Thu, 18 Jun 2015 05:25:30  -0700



personally, I always avoid welding a machined part to the  hull.  I weld a 
flange or nipple to the hull then bolt or thread the  machined part to that. 
 This is my solution to a lack of tooling and  expertise.
Hank --------------------------------------------
On Thu,  6/18/15, James Frankland via Personal_Submersibles 
<_personal_submersibles at psubs.org_ (mailto:personal_submersibles at psubs.org) >  wrote:

Subject: Re: [PSUBS-MAILIST] Idea..?
To:  "Personal Submersibles General Discussion" 
<_personal_submersibles at psubs.org_ (mailto:personal_submersibles at psubs.org) >
Received:  Thursday, June 18, 2015, 4:58  AM

Hi
Alec\Brian, Yes, maybe it  would
push in.  A flat step would probably be better like  you
say.  But maybe im over thinking it as usual.   Probably
not required. Brian, I used the
5\8ths bar  because that's what was specified on the
plans.  However,  its also convenient for using a 16mm
reamer for the  bore. 
regardsJames 
On 18 June 2015 at  03:04,
Brian Cox via Personal_Submersibles <_personal_submersibles at psubs.org_ 
(mailto:personal_submersibles at psubs.org) >
wrote:
Oh  cool !   Thanks Alec
!    I owe you much  over the years
! Brian
--- _personal_submersibles at psubs.org_ 
(mailto:personal_submersibles at psubs.org) 
wrote:

From:  Alec Smyth via
Personal_Submersibles <_personal_submersibles at psubs.org_ 
(mailto:personal_submersibles at psubs.org) >
To:  Personal Submersibles General Discussion
<_personal_submersibles at psubs.org_ (mailto:personal_submersibles at psubs.org) 
>
Subject:  Re: [PSUBS-MAILIST] Idea..?
Date: Wed, 17 Jun 2015 16:40:56  -0400

Hi Brian,
I tend to use quite  thick
through-hulls because its easier for me to machine  the
O-ring grooves into the shaft than into the insert. In  my
case its just a matter of the tooling I have on hand. If  you
have the tooling to put the grooves in the insert, half  an
inch is fine for many  applications.
Best,

Alec 
On
Wed,  Jun 17, 2015 at 3:22 PM, Brian Cox via
Personal_Submersibles  <_personal_submersibles at psubs.org_ 
(mailto:personal_submersibles at psubs.org) >
wrote:
Alec,  James,  I'm
using mostly 1/2" stainless rod through-out for  most
all of my hull penetrations ( for valves and  flaps) ,  I
noticed in the example it was a 5/8" rod,  Why such a
heavy duty thickness?  Was that for a  particular
function? Brian

--- _personal_submersibles at psubs.org_ 
(mailto:personal_submersibles at psubs.org) 
wrote:

From:  Alec Smyth via
Personal_Submersibles <_personal_submersibles at psubs.org_ 
(mailto:personal_submersibles at psubs.org) >
To:  Personal Submersibles General Discussion
<_personal_submersibles at psubs.org_ (mailto:personal_submersibles at psubs.org) 
>
Subject:  Re: [PSUBS-MAILIST] Idea..?
Date: Wed, 17 Jun 2015 14:03:17  -0400

Hi James,
I think
with the taper,  this would tend to push in and jam. The idea
is neat, however,  and would probably work fine with a step
instead of a taper. On  the other hand, does an O ring sealed
through-hull ever fail  catastrophically? I've had the
odd drip, but that's all I've bad  as  I've
seen.
Best,
Alec
On
Wed,  Jun 17, 2015 at 12:26 PM, James Frankland  via
Personal_Submersibles <_personal_submersibles at psubs.org_ 
(mailto:personal_submersibles at psubs.org) >
wrote:
Hi  All Seeing as its a
bit quite I thought I would show this  idea.  Its super
simple.... I have been thinking  how
you could stop a leaking through hull.  Thinking of K  boat
type 5\8th through hulls as in the
plans. I  believe Scott had a leak
when he did his deep test due to a  faulty O ring?

Anyway, here is my idea.   It
would take a little bit more machining, but not  much. 
Machine the 5\8ths bar with a taper on the  protruding
part and a taper on the top to help push the bar  through. 
(I did that on mine anyway).  The handle is  made with a cam
type end. 

If you get  a
leak, you can pull the handle up.  The bar would be  pulled
up, forcing the taper to jam into the penetrator,  hopefully
stopping most of the leak.  I suppose you could  even
machine a matching taper into the start of the through  hull
to match? I suppose the bar could get
pushed  through and jam on its own.  That's  a
possibility. Pic
attached. Kind
RegardsJames 
​

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