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Stevie >My drysuit is so old that I am about to get a new one in a week or two. What should I go for, >crushed neoprene/membrane? I dive every weekend here in the English Channel >but make a lot of overseas trips so I would prefer something much lighter than > my current 8mm neoprene! The issue is that the dry suit should not compress at depth. The membrane and properly crushed neoprene such as the DUI, work well. If a consideration is the weight, then go for a membrane. This is lighter and dries more quickly. The DUI 450 looks really nice, but I have not dived one. >I plan to get a set of wings and start using doubles. At the moment like most Brits >I dive a single cylinder with a pony. What are your thoughts on a wing system that >I can use at home for doubles and with a single on those frequent trips where doubles >(rentals) are rarely available? You can use a set of double wings with a single, but it is not ideal - too big and floppy. I did this for one trip which was going to be a one-off (since I rarely dive a singles) - however, when it looked like I might be doing more single cylinder diving, I bought a 27 lb. Halcyon wing. So, for your diving you'll need two wings: one for doubles, one for singles. >From what I can fathom the DIR system puts a lot of dependancy on the buddy >(redundant timers etc?). What is the DIR thinking with regard to such equipment > under conditions of low vis and strong currents? There was a long and pointless argument (IMHO) that raged on techdiver a while ago on this subject. You should make sure that your arms are not cluttered - so it is easy to get in and out of your harness and do not offer a snag potential. The real message behind this long and pointless argument was that your mindset should be that that your buddy is integral to your system. If you feel the need to carry a spare depth gauge, then the only place to carry it is clipped off in your pocket. BTW, don't start going down the road of thinking that there is something special about diving in the UK (cold and lower vis. But great wrecks!) and that this requires change to DIR. For cold water, you wear increased insulation (e.g. gloves and thicker under suit) and use larger bolt snaps - that's about it. >Whats wrong with using a computer? (I am sure I rewad somewhere that computers were not considered DIR...Todds >pages I think!) I always carry deco tables but generally rely on my computer when doing simple wreck dives in the 100->130ft range. The main consideration using a computer is that people place too great an emphasis on it. That is, they assume the computer is "correct" and that they don't learn about deco. Consider the dive profiles. No stop dives are pretty easy to carry tables and so this is a non issue a BT will suffice. Shallow, say up to 40m, are also easy to carry tables and work out the deco since it doesn't vary rapidly WRT bottom time. Looking at this another way, decompressing from shallow dives is quick and if you do happen to a little more deco due to a square profile table vs. a slightly multi-level profile (computer-based) wreck dive, then so what, it would be minutes in any case. Deeper dives are slightly more difficult, relatively speaking. Take a UK wreck dive with a variation of 5m in depth. This depth change has less significance at 50m than it would have at 30m - profile comes closer to a square profile at 50m than at 30m. Also, this is the point when getting your deco right is more important and where a few more minutes on the bottom will add considerable time to your deco. Commercial computers are designed not to get you bent. That is to avoid the manufacturer from legal action. Most are considerably padded and do not support deep stops directly. Few support multiple gas mixtures. In short, you'll find that for most deeper dives, especially those using oxygen and other Nitrox mixtures for deco, you'll be able to get out of the water using a bottom timer faster than someone on a computer. If you are looking for a program then Decoplan from GUE is easy to use and allows you to determine the amount of safety in your profile on a meaningful basis, rather than an arbitrary percentage "safety" factor. It can be ordered electronically and downloaded. In expensive too! Others are available as shareware. David Shimell Email: shimell@se*.co* <mailto:shimell@se*.co*> Project Manager, IBM NUMA-Q, Sequent Computer Systems Limited, Weybridge Business Park, Addlestone Road, Weybridge, Surrey, KT15 2UF, UK registered in England and Wales under company number: 1999363, registered office as above -----Original Message----- From: Stevie [SMTP:Steven@ha*.fr*.co*.uk*] Sent: Friday, February 18, 2000 5:41 PM To: TechDiver@aquanaut.com Subject: DIR & low viz wreck diving Hi all, I have been lurking here for quite a while and and feel I have picked up a lot of useful info. I have followed just about all the links that have been posted at various times and am really looking forward to reconfiguring my setup (I remember the freedom of movement I had with a backpack rather than my BC!). I guess this reconfiguring is gonna cost me plenty so I am hoping someone can answer a few questions and set me on the right track. My drysuit is so old that I am about to get a new one in a week or two. What should I go for, crushed neoprene/membrane? I dive every weekend here in the English Channel but make a lot of overseas trips so I would prefer something much lighter than my current 8mm neoprene! I plan to get a set of wings and start using doubles. At the moment like most Brits I dive a single cylinder with a pony. What are your thoughts on a wing system that I can use at home for doubles and with a single on those frequent trips where doubles (rentals) are rarely available? From what I can fathom the DIR system puts a lot of dependancy on the buddy (redundant timers etc?). What is the DIR thinking with regard to such equipment under conditions of low vis and strong currents? Whats wrong with using a computer? (I am sure I rewad somewhere that computers were not considered DIR...Todds pages I think!) I always carry deco tables but generally rely on my computer when doing simple wreck dives in the 100-130ft range. Stevie -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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