[PSUBS-MAILIST] Hp valves

Fri Jan 22 17:57:07 EST 2016

Brian,just looked up the G.L. rules Section 9 piping systems, pumps & compressors.It says 1.2 Pipes which are led thriught the pressure hull are to be fitted with 2 shut off valves.One of which is to be fitted immediately at the hull wall.    In 3.3 it says " The compressed air supply is to be carried in at least 2 separate banks of receivers with thesame total volume."Alan

      From: Alan James via Personal_Submersibles <personal_submersibles at psubs.org>
 To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
 Sent: Saturday, January 23, 2016 11:31 AM
 Subject: Re: [PSUBS-MAILIST] Hp valves

Brian,can you split the HP air in to two lines so you have two HP lines coming in.That way if one line failed you would have a back up. Also if a HP line rupturedor connection broke, then you would only have half the pressure in the hull.Inside my ambient I never see HP air, but I have two separate air systems& valves to use both simultaneously or separately.I am not sure what other psubbers do. This is bound to be covered in the Busby book.   I have heard reference to  subs being stuck in the mud through sitting on the bottom& coming up carrying a load of extra weight in the form of mud. I noticed in Carsten'svideo that he sat on the bottom & pivoted. I am guessing to let the divers out, butsounds like a good practice on a muddy sea bed.Alan

      From: Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org>
 To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
 Sent: Saturday, January 23, 2016 10:23 AM
 Subject: Re: [PSUBS-MAILIST] Hp valves

Alan,   The air would most likely vent thru the hatch and then I'd be at whatever pressure the ambient water pressure would be .  If there was no air to surface I guess I'd have to bail.   I will have an additional tank outside the hull for filling the ballast however.  That will be for raising and lowering the sub with scuba while out side the sub.  I was thinking it would be kind of neat to set it on the bottom in about 30' water. That way I wouldn't have to anchor it ! Brian

--- personal_submersibles at psubs.org wrote:

From: Alan James via Personal_Submersibles <personal_submersibles at psubs.org>
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
Subject: Re: [PSUBS-MAILIST] Hp valves
Date: Fri, 22 Jan 2016 17:51:26 +0000 (UTC)

Hi Brian,I questioned G.L. on a number of items in thier rules for submarines& there are some grey areas that you would have to argue the point overwith an inspector.One general rule is that no one failure can cause a major event.If the pipe failed at that elbow & you couldn't stop the flow of HP air,what sort of pressure could you be left with in the hull?Would you be able to blow the ballast tanks if you lost your airfrom that failure or do you have a redundant air supply?Cheers Alan

      From: Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org>
 To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
 Sent: Saturday, January 23, 2016 6:34 AM
 Subject: Re: [PSUBS-MAILIST] Hp valves

ABS says " as close as possible"  I guess I'm ok with a short nipple coming off a elbow. Brian

--- personal_submersibles at psubs.org wrote:

From: Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org>
To: "PSubs " <personal_submersibles at psubs.org>
Subject: [PSUBS-MAILIST] Hp valves
Date: Wed, 20 Jan 2016 08:34:43 -0800

Is there any distinction as to how close a HP shut off valve or check valve has to be to the hull penetration so as to meet ABS requirements?   Can there be a short nipple between an elbow and the valve for instance? Brian Cox_______________________________________________Personal_Submersibles mailing listPersonal_Submersibles at psubs.orghttp://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
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