<div dir="ltr">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.<div><br></div><div>Best,<br><br>Alec<br><div><br></div><div><br></div></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Jun 18, 2015 at 10:55 AM, Brian Cox via Personal_Submersibles <span dir="ltr"><<a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">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?<br>
<br>
<br>
Brian<br>
<br>
--- <a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a> wrote:<br>
<br>
From: hank pronk via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br>
<span class="">To: Personal Submersibles General Discussion <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br>
Subject: Re: [PSUBS-MAILIST] Idea..?<br>
</span>Date: Thu, 18 Jun 2015 05:25:30 -0700<br>
<div class="HOEnZb"><div class="h5"><br>
<br>
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.<br>
Hank --------------------------------------------<br>
On Thu, 6/18/15, James Frankland via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:<br>
<br>
Subject: Re: [PSUBS-MAILIST] Idea..?<br>
To: "Personal Submersibles General Discussion" <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br>
Received: Thursday, June 18, 2015, 4:58 AM<br>
<br>
Hi<br>
Alec\Brian, Yes, maybe it would<br>
push in. A flat step would probably be better like you<br>
say. But maybe im over thinking it as usual. Probably<br>
not required. Brian, I used the<br>
5\8ths bar because that's what was specified on the<br>
plans. However, its also convenient for using a 16mm<br>
reamer for the bore. <br>
regardsJames <br>
On 18 June 2015 at 03:04,<br>
Brian Cox via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br>
wrote:<br>
Oh cool ! Thanks Alec<br>
! I owe you much over the years<br>
! Brian<br>
--- <a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a><br>
wrote:<br>
<br>
From: Alec Smyth via<br>
Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br>
To: Personal Submersibles General Discussion<br>
<<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br>
Subject: Re: [PSUBS-MAILIST] Idea..?<br>
Date: Wed, 17 Jun 2015 16:40:56 -0400<br>
<br>
Hi Brian,<br>
I tend to use quite thick<br>
through-hulls because its easier for me to machine the<br>
O-ring grooves into the shaft than into the insert. In my<br>
case its just a matter of the tooling I have on hand. If you<br>
have the tooling to put the grooves in the insert, half an<br>
inch is fine for many applications.<br>
Best,<br>
<br>
Alec <br>
On<br>
Wed, Jun 17, 2015 at 3:22 PM, Brian Cox via<br>
Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br>
wrote:<br>
Alec, James, I'm<br>
using mostly 1/2" stainless rod through-out for most<br>
all of my hull penetrations ( for valves and flaps) , I<br>
noticed in the example it was a 5/8" rod, Why such a<br>
heavy duty thickness? Was that for a particular<br>
function? Brian<br>
<br>
--- <a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a><br>
wrote:<br>
<br>
From: Alec Smyth via<br>
Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br>
To: Personal Submersibles General Discussion<br>
<<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br>
Subject: Re: [PSUBS-MAILIST] Idea..?<br>
Date: Wed, 17 Jun 2015 14:03:17 -0400<br>
<br>
Hi James,<br>
I think<br>
with the taper, this would tend to push in and jam. The idea<br>
is neat, however, and would probably work fine with a step<br>
instead of a taper. On the other hand, does an O ring sealed<br>
through-hull ever fail catastrophically? I've had the<br>
odd drip, but that's all I've bad as I've<br>
seen.<br>
Best,<br>
Alec<br>
On<br>
Wed, Jun 17, 2015 at 12:26 PM, James Frankland via<br>
Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br>
wrote:<br>
Hi All Seeing as its a<br>
bit quite I thought I would show this idea. Its super<br>
simple.... I have been thinking how<br>
you could stop a leaking through hull. Thinking of K boat<br>
type 5\8th through hulls as in the<br>
plans. I believe Scott had a leak<br>
when he did his deep test due to a faulty O ring?<br>
<br>
Anyway, here is my idea. It<br>
would take a little bit more machining, but not much. <br>
Machine the 5\8ths bar with a taper on the protruding<br>
part and a taper on the top to help push the bar through. <br>
(I did that on mine anyway). The handle is made with a cam<br>
type end. <br>
<br>
If you get a<br>
leak, you can pull the handle up. The bar would be pulled<br>
up, forcing the taper to jam into the penetrator, hopefully<br>
stopping most of the leak. I suppose you could even<br>
machine a matching taper into the start of the through hull<br>
to match? I suppose the bar could get<br>
pushed through and jam on its own. That's a<br>
possibility. Pic<br>
attached. Kind<br>
RegardsJames <br>
<br>
<br>
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</div></div></blockquote></div><br></div>