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I'm just getting started in this arena, but I came across a nice program called "Under Pressure" for examing pressure hulls. As a newbie it is interesting to see how various shapes and materials respond under pressure. My first project is going to be an unmanned vehicle to photograph the shipwrecks in the great lakes. I assumed PVC would be sufficient for this and was shocked to see in Under Pressure that it would fail at a mere 25 ft (based on the schedule I had planned to use). I'm not putting life at risk yet, but this saved me some $$ replacing electonics and really opened my eyes to realize that I need to KNOW what will and will not work. Is Under Pressure a commonly used program? I downloaded it from www.deepsea.com in the resources section. Dan > Date: Fri, 10 Dec 2010 12:50:20 -0800 > From: irox@ix.netcom.com > To: personal_submersibles@psubs.org; personal_submersibles@psubs.org > Subject: Re: [PSUBS-MAILIST] Design depth > > > Just for another data point, mine: > > Predicted hull failure depth: 3400m > Planned Operational depth: 300m > Planned test depth: 600m > > This is of course subject to change, the two biggest factors > being out of round of the hull and funds available for tests. > I could potentially save a lot of money by halving the > operational depth. > > Ian. > > > -----Original Message----- > > From: JimToddPsub@aol.com > > Sent: Dec 9, 2010 7:42 PM > > To: personal_submersibles@psubs.org > > Subject: Re: [PSUBS-MAILIST] Design depth > > Hi, Alan, > > In my mind I had picked up "design to twice the operating > depth." I plan to test to 2/3 of the design depth (US Navy standard) > which is the same thing as 133% of the operating depth. > Therefore: > > Operating Depth 300' > Test > Depth 400' > Design > Depth 600' > > Those numbers might change slightly during the design process, > but the proportional relationships should stay the same. > > Jim > > > In a message dated 12/9/2010 8:13:19 P.M. Central Standard Time, > alanjames@xtra.co.nz writes: > > Hi Jim, > I remembered the discussion but forgot the details. > I used to hear all the time on Psubs that you test your sub to > twice your maximum > operating depth, unmanned, for an hour. This might not be a bad rule for > home builders > who aren't going through a certification inspection process; & may be > using blown domes > with their inherent stresses & weaknesses. Also there is the aging > process that must weaken > the hull, that should be accounted for. I'm still looking at making my > hull out of > fiberglass & there's a bigger margin of error required for that > material. > Alan > > > ----- Original Message ----- > From: > JimToddPsub@aol.com > To: personal_submersibles@psubs.org > > Sent: Friday, December 10, 2010 12:31 > PM > Subject: Re: [PSUBS-MAILIST] Design > depth > > > Alan, > > My design depth is 600 ft. Operating depth is 300 > ft. Therefore required test depth would be 375 ft. Failure depth > must be slightly deeper than 600 ft. > > What test depth would you consider to be best based on the > above? I would have thought 400 ft. which isn't much more than > the standard. We had an online discussion of this in early > October. I'll forward my last post which includes the comments of > others. > > Thanks, > Jim > > > In a message dated 12/9/2010 2:45:05 P.M. Central Standard Time, > alanjames@xtra.co.nz writes: > Thanks, > that's a lot smaller margin than I thought, or would > be happy with myself. > Alan > ----- Original Message ----- > From: > "Jon Wallace" <jonw@psubs.org> > To: > <personal_submersibles@psubs.org> > Sent: Friday, December 10, 2010 > 2:25 AM > Subject: Re: [PSUBS-MAILIST] Design depth > > > > > > > I believe for certification ABS requires the sub to be tested to > 25% > > above its maximum operating depth. So if your max op > depth is 100 feet > > they would require it to pass testing at 125 > feet. > > > > On 12/9/2010 2:44 AM, Alan James wrote: > >> > Does ABS or ASME state what your operational depth should be in > > >> relation to your crush depth? > >> & if so is this > different for the view ports. > >> I've read with fiberglass there > is a 4x safety factor where human life > >> is > concerned. > >> Alan > > > > > > > > > > > ************************************************************************ > > > ************************************************************************ > > > ************************************************************************ > > > The personal submersibles mailing list complies with the US > Federal > > CAN-SPAM Act of 2003. 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Your email address appears in our > database > because either you, or someone you know, requested you receive > messages > from our organization. > > If you want to be removed from > this mailing list simply click on the > link below or send a blank email > message to: > > removeme-personal_submersibles@psubs.org > > Removal of your email > address from this mailing list occurs by an > automated process and > should be complete within five minutes of > our server receiving your > request. > > PSUBS.ORG > PO Box 53 > Weare, NH > 03281 > 603-529-1100 > ************************************************************************ > ************************************************************************ > ************************************************************************ > > > > ************************************************************************ > ************************************************************************ > ************************************************************************ > The personal submersibles mailing list complies with the US Federal > CAN-SPAM Act of 2003. Your email address appears in our database > because either you, or someone you know, requested you receive messages > from our organization. > > If you want to be removed from this mailing list simply click on the > link below or send a blank email message to: > removeme-personal_submersibles@psubs.org > > Removal of your email address from this mailing list occurs by an > automated process and should be complete within five minutes of > our server receiving your request. > > PSUBS.ORG > PO Box 53 > Weare, NH 03281 > 603-529-1100 > ************************************************************************ > ************************************************************************ > ************************************************************************ > |