[PSUBS-MAILIST] K-600

[greg cottrell]

Sean,
 
You are correct. Another advantage external rings have is that pushing in on a stiffener (internal frames) reallies on compression strength of the steel and tends to cause the ring to "cone" over as pressure is applied. When it cones, it immediately loses strength because of the changing geometry. 
On the other hand, pulling in on a ring from the inside (as with external frames) is a tensile load and tends to allow the ring to remain perpendicular longer. Eventually the external ring will get "wavy" and fail also.
 
I think internal rings are better for PSUBS however, because most homebuilders are usually using less than perfect methods of welding/ fabrication  and the internal rings are more forgiving.
 
Greg
 
 
 
 


________________________________
From: "cast55 at telus.net" <cast55 at telus.net>
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
Sent: Thursday, October 24, 2013 11:39 AM
Subject: Re: [PSUBS-MAILIST] K-600



External rings will always give you a stronger hull compared to internal for the same hull thickness and ring spacing. The downside is that the welds have to be perfect, but any weld shrinkage that may occur actually acts to deform the hull in a way that increases its strength over that of the nominal geometry.
Sean



vbra676539 at aol.com wrote: 
PC-8 has 3/8" wall thickness on the hull cylinder, the same as the 600, but was rated 200 feet deeper by ABS, even though it has a larger radius (21" as opposed to 18"). The ring stiffeners on the 8 are external and the conning tower larger. Makes you wonder what the deal is for figuring operating depth. Perry went to half inch for PS-2 which was the same boat but rated at 1000'. Hmmm.
>Vance
>-----Original Message-----
>From: greg cottrell <jgcottrell2002 at yahoo.com>
>To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
>Sent: Thu, Oct 24, 2013 10:24 am
>Subject: Re: [PSUBS-MAILIST] K-600
>
>
>I thought that George said they were .625" but I could be wrong.
> 
>
>
>
>________________________________
>From: Jon Wallace <jon.wallace at yahoo.com>
>To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
>Sent: Thursday, October 24, 2013 10:14 AM
>Subject: Re: [PSUBS-MAILIST] K-600
>
>
>It was an engineer hired by the company that commissioned and purchased the 600.  His calculation requirements for the heads came out a little bit thicker than what George had calculated.  I believe George spec'd .5 inch and the company's engineer spec'd .5625 inch.
>
>--------------------------------------------
>On Thu, 10/24/13, greg cottrell <jgcottrell2002 at yahoo.com> wrote:
>
>Subject: Re: [PSUBS-MAILIST] K-600
>To: "Personal Submersibles General Discussion" <personal_submersibles at psubs.org>
>Date: Thursday, October 24, 2013, 9:25 AM
>
>George attributed the miscalculation in the weight
>of the 600 to second guessing the thickness of the heads.
>His original design called for thinner heads but
>someone (can't remember who) that George respected
>suggested that they should be thicker. George used the
>thicker heads and then found that the sub wouldn't
>float. He had the hull lengthened by Bath Iron Works to get
>the needed buoyancy back. He
>said he was amazed at how fast they turned the job around- I
>think it was only a few days.
> 
>Greg
> 
>
>
>
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-- 
Sent from Kaiten Mail. Please excuse my brevity.
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