BA_DIVING posts in spring '99 regarding dry suit practices. These have been trimmed for easier reading. --------------------------------------------------------- From: Charlie E Eng Subject: Diving Dry Date: Thu, 25 Mar 1999 22:26:29 -0800 At 47degrees F a Moby's Comfort Shell insulator suit felt OK, but because I was hunting and moving around so much I stayed warmer than what I would expect if I was shooting pictures with a camera. Other dry suit divers mentioned to me that another layer would be needed. I went out and got the fleece (200) pants and tops for $55 and expect to feel quite comfortable. Some other divers are just using the 200-300 Fleece without the shell insulator suit and they're fine. ---------------------------------------------------------- From: Jeff Wang Subject: Re: Warm, but very buoyant Date: Thu, 15 Apr 1999 11:32:49 -0700 (PDT) >> Just about everyone that commented voted against >> using the suit exclusively for buoyancy. > I'm surprised at this. What's the thinking on it? I personally just feel that in the event of a catastrophic tear (from a fish hook, etc), you would then have a very heavy dry suit, and even ditching your weights may not overcome that. Also, I am very worried about streching the seams, causing a leak. Only so many times Tim Ewing is going to fix my suit before he lights up and realizes that he should get paid for it. Also, on a buoyant ascent, you couldn't vent the suit as quickly as a BC. _________________________________________________________ From: "Ian Puleston" Subject: Re: Warm, but very buoyant Date: Thu, 15 Apr 1999 12:54:41 -0700 > Also, on a buoyant ascent, you couldn't vent the suit > as quickly as a BC. Thats true, but even if you use the BC as well, in deep water you'll still have to put quite a lot of air into the suit to combat undergarment compression and stay warm. Hence in the event of a buoyant ascent you'll have the additional problem of needing to vent both the suit and the BC. I'm told that in a real emergency the way to stop a buoyant ascent is to crack open the neck seal. Must admit I've never tried it though! ---------------------------------------------------------- From: Juli Tallino Subject: re: warm but very bouyant Date: Thu, 15 Apr 1999 15:37:43 -0700 (PDT) I strongly recommend that anyone new to a drysuit, take a course. Learning how to vent the suit at the neck and other such emergency procedures are all part of learning how to use this piece of equipment. (better in the pool than in the ocean!) I also think that by only using the suit for bouyancy would help in fine tuning your weight. Just my 2 cents on the matter.:) _________________________________________________________ From: "Baber, Bruce" Subject: RE: Warm, but very buoyant Date: Thu, 15 Apr 1999 18:32:36 -0700 >I'm told that in a real emergency the way to stop a buoyant ascent > is to crack open the neck seal. Must admit I've never tried it though! During my dry suit training, I did do this in a pool. After over inflating a little, the instructor gave me an extra weight belt to hold onto. (The was done as a breath-hold dive to prevent an embolism.) Now I'm upside down at the bottom of the pool. The drill is to let go of the weight, turn right-side up, and then dump air by opening the neck seal ... all before you reach the surface. It was an interesting exercise. But it did show that you could dump a lot of air very quickly, in fact, faster that a BC (if you can get a quick grip of the neck seal; in the class I didn't have gloves on). And because the air is so busy coming out, not much water got in (a cup or two or three). Bruce Baber ---------------------------------------------------------- From: Ruth Justice Subject: RE: warm but very bouyant Date: Fri, 16 Apr 1999 09:59:18 -0700 As a manufacturer of custom drysuits I strongly recommend taking a drysuit specialty course, as there is much more to know about drysuit diving. Also, I even more strongly recommend using a B.C. for you buoyancy, not depending on the suit. The reason we add air to our suits is to prevent what we call "suit squeeze" . Just a couple of shots of air should do the trick. The dump valve should release the air automatically as you ascend. Of course, every instructor has their own opinion and experiences, but I needed to get my two cents in there too. ---------------------------------------------------------- From: "Baber, Bruce" Subject: RE: warm but very buoyant Date: Fri, 16 Apr 1999 13:17:03 -0700 > Also, I even more strongly recommend using a B.C. for you buoyancy, not > depending on the suit. The reason we add air to our suits is to prevent > what we call "suit squeeze" . Just a couple of shots of air should do the > trick. But if you are weighted properly, when you add those "couple of shots of air" to prevent suit squeeze, you are also now neutrally buoyant. I would think that anything you can do to make things more simple (KISS!), the less room there is for errors. I don't think I want to have to keep track of dumping air from 2 devices (my dry suit is not 100% automatic, I have to at least have the presence of mind to lift my arm before the dump valve activates). I know that PADI teaches the suit only approach (at least, that's what my PADI instructor taught) and use the BC only at the surface to bring your head above the water. There are obviously other personal approaches. What method is taught by the other agencies? Bruce Baber ---------------------------------------------------------- From: ges3@ibus.com Subject: RE: warm but very buoyant Date: Fri, 16 Apr 1999 14:59:57 -0700 All: I have a Monterey Bay Drysuit systems custom drysuit. At depth I cannot keep enough air in the suit to keep me buoyant. It leaks out the neck seal quite vigorously. If I keep very trim horizontally, head slightly down as compared to my feet, I can keep enough air in the suit, but as you might suspect this is a dangerous thing to do, since I can get foot-first buoyant really fast. So, I keep very little air in the suit, enough to prevent squeeze, and use the BC for the buoyancy. George E Spalding III ---------------------------------------------------------- From: Sami Laine Subject: RE: warm but very buoyant Date: Fri, 16 Apr 1999 16:47:57 -0700 At 02:59 PM 4/16/99 , ges3@ibus.com wrote: >I have a Monterey Bay Drysuit systems custom drysuit. At depth I cannot keep >enough air in the suit to keep me buoyant. Simple rule of thumb for open water recreational diving with a single tank: Neoprene suit -------------------------- Keep the suit volume comfortable to avoid squeeze, manage loss of buoyancy due to suit compression with BC, just as you would when diving wet. Shell suit --------------------------- (incl. trilaminate, thin compressed neoprene, crushed neoprene) Keep the suit volume about constant through the dive, no reason to touch BC. Now let me throw some blood in the water and don my flame resistant shell suit: Diving with a neoprene suit without using BC is possible, and some people do it all the time; people dived without any buoyancy compensation back when I was born and were doing fine, with a neoprene suit you can stay closer to neutral than you were back then. Some people can manage to keep enough air in the suit to actually stay perfectly neutral. For most divers of today this may be unnecessarily difficult and/or risky. Use the BC to compensate for the suit compression, that's what the darn thing was designed for in the first place and that's why you're dragging it around. Of course with a good shell suit and appropriate underware this is all a non-issue. No suit compression, no loss of buoyancy. Just keep the suit at the same, snug, comfortable inflation level through the dive. Underware compression is a non-issue with appropriate underware (thinsulate, polypro). Of course you can create a problem for yourself by doing something silly, like using neoprene as underwear (yeah, I've seen this...). And since the issue of the weight of the air came up, it's also pretty much a non-issue for a single tank diver. The buoyancy change of my tanks from full to 500psi is under 5 lbs. This is a bit over 2 quarts of extra air in the suit for the shell suit diver at the beginning of the dive, a small difference. If you're dragging along 240cf of back gas in doubles, and a couple of stage tanks things are different, you absolutely use the wing to control buoyancy. But if you're doing that, you're not reading this list for buoyancy advice. Enough, I'm going to pick up tanks. See you tomorrow in Monterey. Sami ---------------------------------------------------------- From: Chuck Tribolet Subject: RE: warm but very buoyant Date: Fri, 16 Apr 1999 18:49:55 -0700 > I can't say how big 6 pounds of lift > is, I'm still trying to figure it all out. A pint's a pound the world around. (roughly) A pint of water weighs about a pound. A pint of air displacing a pint of water gives a pound of lift. Chuck Tribolet ---------------------------------------------------------- From: Rocky Daniels Subject: RE: warm but very buoyant Date: Sat, 17 Apr 1999 05:14:26 Ruth wrote: >As a manufacturer of custom drysuits ... I even more strongly > recommend using a B.C. for you buoyancy, not >depending on the suit. The reason we add air to our suits is to prevent >what we call "suit squeeze" . Ruth must be referring to a neoprene dry suit; her advice only applies to this type of suit. Because of 1) the change in buoyancy as the neoprene shell compresses with depth and 2) the inability of a snug neoprene dry suit to hold enough air to compensate for that change in buoyancy, using the suit for buoyancy compensation is pure gooberness. Confused by a Dry Suit Specialty course that insisted that I use my suit rather than the BC for compensation, it took me awhile to sort this out. Ironically, things didn't fall into place until I had a DM in Hawaii explain the best method for determining when and how much air to add to your neoprene drysuit that things fell into place. (Hint: it only works for male divers and has to do with octave shifts associated with increasing depths). I must emphasis that the situation is exactly the opposite for shell suits made of non-compressible shell material (vulcanized rubber, trilaminates, crushed neoprene). These suits, in combination with bulky undergarments, allows you to weight yourself and adjust the suit's inflation at the surface to achieve neutral buoyancy. As depths change, buoyancy compensation is a simple matter of tweaking the air in the suit. Using the BC at depth with these suits increases the goober factor. Rocky Daniels ---------------------------------------------------------- From: "=?iso-8859-1?Q?Jos=E9_Kirchner?=" Subject: RE: Dry suit loose or tight neck seal Date: Sat, 17 Apr 1999 14:24:45 -0700 RE: Dry suit exchanges going on... I will second previous suggestions and highly recomend a full dry suit course- including learning how to do a quick "tuck and roll" to right one's self properly in a air-in-the-foot situation, as well as the several ways of venting excess air in an ascent emergency. For theose who have been talking about loose neck seals (and those who hate tight neck seals), one answer is the Apollo Bio-seal. This is a loose ring of tacky and very flexible material that fits around the neck and under the seal, introduced to me by a South Australian dive operator (who used to be an ab diver). This seal ain't cheap- US$50.00- but it will make things much drier and more comfortable, and it does last. Check with your Apollo dealer- some don't even know this Bio-seal exists, and it's not even on Apollo's website or catalogue- but it exists and works very well. Safe diving, José in the flatlands ---------------------------------------------------------- From: John Heinlein Subject: RE: warm but very buoyant Date: Sat, 17 Apr 1999 19:59:39 -0700 Bruce Baber writes: > I know that PADI teaches the suit only approach (at least, that's what my > PADI instructor taught) and use the BC only at the surface to bring your > head above the water. Not exactly. I just checked the PADI Advanced Open Water Dry suit dive instructor outline (I expect the Dry Suit specialty is the same, but don't have that handy): the text does advocate using the suit for neutral buoyancy, but the standard does not require it, it merely requires various kinds of successful neutral buoyancy exercises while diving dry. IMHO, this leaves to instructor discretion the approach to use for PADI. My personal opinion, and with my equipment, I find I have _far_ finer control of venting from my BC than my dry suit shoulder valve. I also find (using a laminant dry suit) that having too much suit air means instability as it shifts when I move. So, I personally subscribe to the BCD school of thought, and teach that. My course director teaches that way as well. John. PADI OW Instructor ---------------------------------------------------------- From: "Adventure Sports, Unlimited" Subject: Re: Warm, but very buoyant Date: Sun, 18 Apr 1999 18:43:33 -0700 (PDT) At 09:35 AM 4/15/99 -0700, you wrote: >> Just about everyone that commented voted against using the suit >> exclusively for buoyancy. > >I'm surprised at this. What's the thinking on it? I vote for using the dry suit exclusively for bouyancy. The BC is an emergency back-up system for the dry suit. In fact you hardly need much of a BC because it is simply a back-up. If you use both it's too confusing. Where's the air? The BC is a lousy alternative to the dry suit because it gives your bouancy back, stolen by the pressure, but not the warmth. You add air to your dry suit, you get back your bouyancy and your warmth. Besides the dry suit is a better BC than a BC. You can get even bouyancy throughout your body. Your BC only holds up your front. Thats why dry suit people with minimum BC's can cover more ground---less water resistence and better fluid dynamics. The prime factor is that you don't overweight yourself and have masses of air moving about. The air should be contained primarily in your underwear. A key factor. Most people overweight themselves. dennis, Adventure Sports Unlimited ---------------------------------------------------------- From: "John Lechmanik" Subject: Dry Suits Date: Sun, 18 Apr 1999 20:12:00 -0700 Well I wasn't going to get into this, but since my partner wondered why I didn't say anything, I guess I'll jump in. Yes, they teach you to only use your suit for buoyancy control. I tried this (this is what they taught me at Santa Cruz) for about 1/2 year (and since I dive a lot, that is quite a few dives). It sucked. I had a neoprene dry suit. At the end of the dive, with 400psi left, I was slightly positive at 15 feet. This was the minimum weight I could carry. Still since the suit compresses at depth, I would have to add a LOT of air into the suit (12 plus pounds of buoyancy at depth) which would move all over the place. If I went head down to look into something, I GIANT air bubble would travel down my back to my feet/legs. Finally, I decided to try two systems. This is much nicer. Now I use the BCD on the surface with the suit empty. I add air to the suit (and vent it) to remain minimum air to eliminate squeeze. I use the BCD to control buoyancy. The BCD inflates faster, and deflates faster than the suit which makes this easier. I recently changed to a crushed neoprene suit (and thank god dropped about 4 pounds of weight). I probably could go back to trying to add air to the suit only, but I am real comfortable with the method I use. To ascend, vent the BCD completely, raise left elbow (bring computer up to face if using as ascent meter) and start swimming up. The suit should vent naturally, if you need to vent BCD, pull on the cord (I never could figure out why they teach us to raise the inflator, when pulling on the cord works faster and better). For some reason people try to tell you there is only one way to do things. This is crap. You do what ever makes you comfortable. Take a class, read some books, then practice, practice, and practice. Then you can make you own decisions on how things should be done..... John Lechmanik ---------------------------------------------------------- From: Michael Rys Subject: RE: Dry suit diving, run 3 > I still haven't reduced the neck seal all the way and it being wet > may have made it more difficult to pull on properly. Be careful. Most often you do not need to trim it. If you do you might cut it too short. Having enough seal material allows to move your head, swallow and be sloppy when adjusting the seal. The unconfortable feeling of being strangled will disappear during the dive. > And then jumping in sans weight belt probably didn't help - > I felt an air bubble rush up. Did you do the self-hugging most drysuit divers do after zipping up? This removes the excess air and lets you test your auto dump and will avoid a too big an air bubble. > What I think was happening was that as I inflated, it ran > straight up to the neck seal and opened it up > for water to enter. Hmm, this may be a sign that you have trimmed your neckseal already too much, if this was the cause. If the seal is big enough, the air bubble should not break the seal unless you play Michelin-man. And if it breaks, normally air would gulp out and only little water should come in. Only if your seal is too short, an air bubble could break the seal and leave it open for water to enter. OTOH, did you check that the zipper was fully closed? Sometimes there might be a small leak where the neckseal is fastened to the suit that can easily be fixed with some drysuit glue (happened once to me, probable cause: too much stress on the seal when pulling it over my head, fix: Typhoon sent me glue for free and 10 mins of my time to fix it). Note that these remarks all apply to latex seals; the situation may be different for neoprene seals. Greeting from the PNW Michael