....."Are people considering building military psubs"
It seems to me this debate is at the heart of the reason why we see more "Needlefish" than we do "Kraka", as the hobbyist elongates the design and gets away from the compact research type submersibles.....buoyancy and control.
There is a natural tendency to want it all, autonomy, lockouts, sound gear, manipulators...the works but, compromise is surely the order of the day where these designs are concerned, one or the other, Alvin, Balao or Nuke...decisions decisions!
If these debates do nothing more than re-enforce the basics, I for one find tremendous value in that.
Joe
From: irox <irox@ix.netcom.com>
Reply-To: personal_submersibles@psubs.org
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] VBT's & The Apology
Date: Sat, 26 May 2007 14:15:43 -0400 (EDT)
>
>Wouldn't the SDV be at neutral bouyancy? Otherwise it would
>just plummet to the bottom if it weight 2000 to 3000 pound submerged.
>Undocking a a neutrally bouyant object form another neutrally bouyant
>object won't change the bouyancy of either or require either to do
>any sort of bouyancy compensation.
>
>Are people concidering building military psubs with diver lockouts?
>Military subs are very different from civilian subs, lots of
>standard safety systems are omitted, because they are counter to
>main goals of a war-sub. Things are done differently, people die,
>a lot. While some lessons are useful for psubs, they might not be
>such a good general example for psubs/civil-subs.
>
>2cents,
>Ian.
>
>-----Original Message-----
> >From: Ken F <syber_psubber@yahoo.com>
> >Sent: May 26, 2007 1:09 PM
> >To: personal_submersibles@psubs.org
> >Subject: Re: [PSUBS-MAILIST] VBT's & The Apology
> >
> >Vance,
> >
> >Almost purely for the sake of argument at this point.
> >It's not un-heard of for a Naval Submarine to dispatch a squad of SEALS, and all of their equipment, out through the TORPEDO TUBES, as well as undocking an SDV (submersible diver vehicle) from the deck of the submarine. With the weight off all the men, equipment, and SDV, I'd figure it at roughly 2000 to 3000 pounds. So you're telling me that a Naval Submarine intentionally grounds itself if it's going to offload a ton to a ton and a half of mass, because there's no safe way of doing it otherwise?
> >I wanted the *method*, which is where I think you're missing the point.
> >
> >Ken
> >
> >vbra676539@aol.com wrote: Age and evil intentions will outdo youth and smug every time. Deal with it. What you are suggesting is not new, merely dangerous. Figure a way to "anchor" in midwater, or perform underway with enough mass (as in military subs) and you'd be fine. Otherwise, problems compound. Don't take it personally. I was 23 once, as well. The difference between us is that you're coping with it and I'm merely glad it's over. Vance
> >
> >
> >-----Original Message-----
> >From: Ken F
> >To: personal_submersibles@psubs.org
> >Sent: Sat, 26 May 2007 4:23 am
> >Subject: Re: [PSUBS-MAILIST] VBT's & The Apology
> >
> > Vance,
> >
> > Wow, I really had no idea that what I was suggesting was so taboo. You make it sound as though I violated some oceanic statute just by bringing it up. I had tried to stress early on that at 23 I'm a bit young, and I realize that, but maybe if you can calmly inform me of any really horrible no no noooo's then possibly you can just drop me a note or something? Scolding me publicly is hardly a conducive way to promote the free flow of information and subject matter in a board which is not governed by insurance policies nor commercial institutions.
> >
> > Furthermore... I think that your view of the future of submersible use, especially by private contractors, is archaic. Actually, I might leave the dinosaurs out of it and just leave it at "outdated". I realize that the older crowed here spent alot of time either on the surface, or on the bottom, but never in a capacity where a diver might need to exit the sub at a spot somwehere BETWEEN the surface and the bottom. I'd imagine that I'm a whole new species of human who can find extremely usefull ideas for establishing a protocol of correct procedure and safety for exiting and reentering a sub while in a column of water, and not grounded at the bottom.
> > I'm sure there are several possible scenarios for the situation. I like to think "outside the bun". It's a nasty habit that tends to get me promotions. The more informed I am about several ways I can do something, the more contingencies I can come up with when I need to make decisions. I'm not sure that limiting myself with conventional taboos is necessary.
> >
> >I also like to be safe though.
> >
> >Ken
> >
> >
> >vbra676539@aol.com wrote:
> > We've been through this. no, No, No, NOOOOOOO!!!!! The boat WILL NOT be neutral, or even close to it while a diver is outside. Live boating, as moving the sub while the diver is outside is called, is strictly forbidden by insurance companies, commerical dive procedures and common sense. You build the boat to flood negative in excess of the BOTH diver's weights, as your tender may in fact have to get out to serve as rescue or back-up diver. Mid-water diving??? Sheesh! Come on, guys. Vance
> >
> >
> >-----Original Message-----
> >From: ShellyDalg@aol.com
> >To: personal_submersibles@psubs.org
> >Sent: Fri, 25 May 2007 12:51 am
> >Subject: Re: [PSUBS-MAILIST] VBT's
> >
> > Hi. This is in response to the diver weight compensation question.
> > Every dive trip in your sub requires careful measurement of what you bring on-board.
> > If the dive plan calls for a diver to exit the sub while at depth, I would think that it would be better to add buoyancy to cover the divers extra weight while on-board, and then dump that buoyancy ( air bubble ) when the diver exits the sub, there-by maintaining neutral buoyancy while the diver is outside.
> > When the diver is back on-board, blow the required amount of air back into the trim tank ( a measured amount of water to compensate for exactly how much the diver weighs ) and again maintaining neutral buoyancy.
> > A sub with a diver lock-out function would need a bigger trim tank than a sub without that capability.
> > Don't forget to calculate how much air the diver displaces with his body, as this will figure into the required additional buoyancy too.
> > You don't need a separate pump system, nor would that be desirable, to let a diver exit and re-enter the sub. The lock-out chamber is controlled by air pressure, and any small amount of water that remained within would be easily compensated for by the additional trim tank volume.
> > You WILL need some means of dumping the air from the lock-out chamber once the water is blown out and the hatch is closed so the diver is once again at one atmosphere. This needs to be monitored closely so a diver has time to dump the excess nitrogen absorbed by his body tissues and blood. A diver lock-out chamber is really much like a de-compression chamber, but is located inside another chamber ( the sub's pressure hull ) so a compressor to drive out the additional air is required.
> > Frank D.
> >
> >
> >
> >
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