Ken,
If I remember correctly, the Brit escape was made from a commercial sub not much bigger than some PSUBs. Yes there are a lot of issues here that need a LOT of forethought (this forethought will also help minimize getting into those situations that result in a DISSUB). Believe me, a 100 ft. escape is not easy especially when clothed, with out a proper vest to make a buoyant ascent, and a small bail-out bottle that could be accomofdated in most PSUBs.
I don't question your experience at all, there ar a lot of issues here that most don't think of due to no opportunities for practical experience.
R/Jay
-----Original Message-----
From: Ken F
Sent: May 8, 2007 11:50 PM
To: personal_submersibles@psubs.org
Subject: RE: [PSUBS-MAILIST] Loss of Buoyancy Accident (was Submarine motors)
Mmmm, in reading over your letter I also realized that the statistics for Escape from a submersible at 600 feet has to do with military submersibles, and I think its a hard push to compare them to psubs. I'm pretty certain that if a normal psub lost hull integrity at 600 feet, the resulting explosive change in pressure would cause serious internal problems and most "survivors" who could manage to equalize, flood, and escape from a hatch would rarely live much past surfacing. There are huge pysiological factors at play there, as well as small things like, lack of space to maneuver for example, and the fact that a military submarine would have a presumable larger trapped air supply to work with (depending on the problem).
However, in a small sub, It's probably that depending on the severity, anything short of a rapid recovery with minimal pressure loss would require efforts to remove the person using scuba and deco on the way to the
surface. It would take some time just to realize that a problem has occured. And I'm finding more and more that here on Psubs there are two distinct schools of though, and one of them doesnt venture much past 100 or 200 feet. The other school are the die-hard psubbers who want to create extremely expensive subs, which are capable of actually a great deal. Whether they have the finances for it, or if they can manage to do it for a somewhat more reasonable cost.
In order to show you that I'm not purely argumentative... I'll admit that the suggested range that I'm arguing for, namely, the 100 to 200 foot depth range... is the most likely candidate for an emergency ascent from the bottom =) Cheer up, us youngins are all hot air & vinegar. I may be young but I used to work in the dive industry, in sales, and have visited Aqualungs facilities several times for
further education and certification. Along with my various dive certs, I've made 200+ dives off of the SoCal Coastline, Channel Islands, and inland lakes, which usually dont have the crystal visibility of tropical waters, and requre more stringent use of navigational concepts and solid scuba skils.
Ken
"Jay K. Jeffries" <bottomgun@mindspring.com> wrote:
Ken,
I am very familiar with SubSalv and their products (they have made me a lot of money)…use to live close to their corporate headquarters in RI. Your original premise was for just a loss of buoyancy and did not include loss of hull integrity. In the case of loss of hull integrity, statistics show that an emergency escape (subject of my second paper for this summer’s conference and some fun, realistic practice with the S.S. Excrutiator) is the preferred method as compared to waiting for heavy lift to bring the hull to the surface for escape. Record free ascent was from over 600 fsw by the British to demonstrate the
practicality of the method. Recover the completely flooded hull late.
I was the one that provided numbers for wrecks in the vicinity of Holland, MI. May have a better source; awaiting software validation keys. It is Clive Cussler not Dirk (the name of his major protagonist in his novels). Good luck getting anything from him. Most divers and marine historians guard their numbers like gold. There is a WW I U-boat out in the middle of the Lake sunk by gunfire after the war.
R/Jay
Respectfully,
Jay K. Jeffries
Andros Is., Bahamas
A skimmer afloat is but a submarine, so poorly built it will not
plunge.
From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of Ken F
Sent: Tuesday, May 08, 2007 9:34 PM
To: personal_submersibles@psubs.org
Subject: RE: [PSUBS-MAILIST] Loss of Buoyancy Accident (was Submarine motors)
Jay,
Thanks for the info!!
It was very eye opening. I've only conducted minor salvage on smallish to medium objects, and spent some time clearing a spot of large rocks and some wreckage. I suppose if a diver could attatch my system to the sub, he could most likely manage to cut away the drop weight, or some such, true... I"m just trying to play on the outter edges of the contingency ring. I've done quite a bit of communicating with SubSalve, and my "system" actually used two lift bags, but they were located almost next to eachother, which keeps things under better control. Most of subsalves "pro" and "commercial" series lift bags are open bottomed, so if you fill to the brim and it suddenly sucks loose, the air comes bubbling out the bottom. With added dump valves it seemed a viable solution. Wouldnt a (DISSUB) which was partially flooded be difficult to drag to the surface using normal surface crafts and a
line?
And to whomever else it was who mentioned the wrecks.... I'm working a couple angles, I've found some other databases, and I'm actually speaking with Dirk Cussler over at NUMA. Apparently they're working on bringing up a DC-4 at the moment that went down some years ago, they have tons of compiled data, as well as network with other people. I'll see if i can find something closer?
Ken
Heck we could always sink Les's new boat, and then go look at it!!!! =)
"Jay K. Jeffries" <bottomgun@mindspring.com> wrote:
Depending on the hull design, a submersible may actual lose some buoyancy when bottomed out. In addition, there may be bottom suction that must be broken through to start ascent. Due to the bulk of the hull, you will probably find it difficult to control two bags and if there is loss of buoyancy when bottomed or bottom suction present, the stranded submersible (DISSUB) will make a VERY rapid ascent that could cause deco issues for you.
When conducting a professional salvage, the lift bag should be sized to the load to be lifted so that it is near 100% filled with air when lifting starts…thus buoyancy will be automatically controlled on ascent as the expanding lift gas will be vented off instead of increasing lift. Loss of buoyancy due to bottoming or bottom suction should be negated with a much smaller bag in addition to the main bag; this can be quickly dumped once ascent is started. Additionally bottom suction can be broken by jetting air under the submersible. The most maddening thing is to have 1 ½ tons of lift rigged to a goody on the bottom in 120 fsw, having it buoyant enough to bounce on the bottom and relatively easy to move, and then find that you need one more small bag, a bit more lift gas, and more bottom time. With an impending gale rolling in, it really hurts to have to cut the lift away, return to the surface empty handed, and
have to chase your lift bags downwind.
You also have to take into consideration at what depth the DISSUB is at when starting the lift, the deeper the stranding the more gas you are going to need for lift. A much simpler solution that involves a lot less logistics and is often much more timely is to just attach a heavy line to the DISSUB and haul it to the surface. Two men on the surface can easily pull up a 200 pound load to the surface. Once in shallow water, it should be easy for a diver to knock loose the emergency ascent weight to gain sufficient buoyancy to put the conning tower out of the water for crew egress. We have raised a 28 ft. Novi lobster boat in
130 fsw in New England with little more than a good anchor winch. Once at the surface, we slung it between two boats and pumped it out…it was back lobstering in 3 days. That water is cold in December!
This issue and many others are being reviewed for the paper Contingency Planning that I will be giving this summer at the Holland gathering.
PS: A properly rigged 55-gal. poly drum has about 465 lbs of buoyancy in salt water if I remember correctly.
A skimmer afloat is but a submarine, so poorly built it will not plunge.
From: owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org] On Behalf Of Ken F
Sent: Tuesday, May 08, 2007 3:15 PM
To: personal_submersibles@psubs.org
Subject: RE: [PSUBS-MAILIST] Submarine motors
Yes, MBT's are flooded, as well as VBT(s), and the weight is not droppable (i was goin for worst case scenario). I dont know if it applies, but if it ever did, it'd sure be a crappy situation.
150lbs? So If I controll the ascent using two 250lbs Commercial lift bags with dump valves, and on each side on the underside have strapped a 250lb lift pillow bag... hmm, I suppose i'd really have to try it in order to see if it'd work or not... I figured on using the commercial lift pieces on whatever hooks are used with a crane, and just under the surface, pillow bags would be
attatched to the sides, and the commercial bags could be used as well if necessary. One of the other methods of dual-side flotation when the surface has been aquired is modified 55 gal poly drums. But that really takes away from the "portable" issue.
Ken
I figured on overkill in case the sub had been partially flooded.... in either case an extremely controlled descent would be required incase the occupant lost 1ATA.
"Smyth, Alec" <Alec.Smyth@compuware.com> wrote:
When you say "deballasted" do you mean a situation where the MBTs are flooded and for whatever reason you cannot blow them? The buoyancy of the sub in that condition is normally zero. So any little bit of buoyancy will raise you, but what you'd really need is enough buoyancy to lift the coning tower clear of the water to open the hatch. In the case of a K-250, on account of the acrylic dome you will need more than in a sub with a flatter hatch. I'd have to work out some basic numbers, but off the top of my head I'd say about 150 lbs should do it for the K-250.
From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of Ken F
Sent: Tuesday, May 08, 2007 10:45 AM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] Submarine motors
I'm
actually in Chicago, but in 3 months I'll be moving back to Southern Cali. (somewhere between Lancaster/Palmdale and Bakersfield). I have alot of design concepts for almost every stage of my sub's production kickin around in my head, in various forms of dissaray, and some things out on the computer, but currently im spending every spare minute trying to learn how to use SolidWorks 2004 so that I can put something together that's more finite and...um...solid? Lol.
The submarine escape simulator sounds really interesting..
I'd like feedback from everyone on a project I'm working on. Its a highly portable, compartmentalized, flexible, custom, adjustable (more adjectives!!!!) system for diver assisted submarine recovery in a condition of full ballasting loss, and takes into
consideration the possibility of not being able to release the manual drop weight.
I'm a certified and well practiced deep diver and have been (breifly) down to 220 feet on normal air. So i'm comfortable with depths that some people might not be comfy trying to escape unnasisted from. Anyhow, I've contacted a couple salvage companies, and even gotten OEM pricelists in order to put my system together. If I can get a working iteration of it before the conference I'd like to try it on someone's "artificially stricken" sub if we have time. It is designed not only to raise the sub to the surface completely standalone of the sub's own ballasting system, but in a controlled manner and also, to provide enough freeboard at the surface for safe evacuation and sub stability.
What I need from you all....
1) A rough idea of how many pounds of positive buoyancy would be required to raise your
stricken sub. Note: im not looking for the dry weight of your sub, rather the um..."wet" weight, your buoyancy displacement when fully deballasted including your dropweight.
2) If you think this is stupid or not... tell me. I've already got it all figured out, have already begun purchasing supplies.
Ken
I wasnt sure yet if I was intending to produce a completed product, and market it extremely affordable to the Psub community, or if I just want to get units out there to our various locations in order to add an extra degree of safety for all my water-faring brethren...
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