Chill factor in two-tank dives
As a PADI Divemaster and diving doctor who has dived in both Caribbean and UK waters, I felt I should reply to Neil Anderson's comments on two-tank dives and surface intervals (How Safe Are Two-Tank Dives?, Off-Gassing, September).
PADI Open Water Divers are trained to compensate for the effect of cold water temperatures by adding 4m to the depth dived when using tables. This is a simple device, and has been superceded by some dive computers which take temperature into account in their calculations, and alter bottom time accordingly.
A diver diving in cold waters is relatively warm on starting the dive and can absorb far more nitrogen. The deepest parts of the dive are usually done first, so the diver absorbs most nitrogen at this point. As the diver cools towards the latter part of the dive, off-gassing of nitrogen might be less effective, whether because of shallower breathing, skip-breathing, less effort or for physiological reasons, so increasing the risk of DCI as compared to the same dive in warmer waters.
A 60 minute surface interval after a coldwater dive leaves the diver with comparatively more nitrogen with which to start the second dive. Pushing the limits of your computer also increases the risk of DCI, but it can still occur within the limits! The more I learn about diving medicine, the more I err on the side of caution.
Keep well within your limits, open your eyes to the risk factors that increase the incidence of DCI, such as fitness, dehydration, smoking, cold, alcohol or pre-existing illness, and increase your safety margins by reducing depth/bottom time, extending the safety stop, and increasing the surface interval.
All textbook stuff but easy to overlook.
I have found diving in the UK far more stressful than in the Caribbean. Hoods and bulkier wetsuits or drysuits increase the claustrophobia, poor visibility and more elusive sea life annoys, and low water temperatures make certain extremities run for cover. But just try to stop me diving here!
Dr Dominic Gonzalez, Glasgow
Can someone be addicted to diving without actually being a diver? I am.
I love the theory, the gear, the talk of sunken wrecks, the best dive places visited, the excitement and preparations before my husband dives and I have read the PADI Open Water manual from cover to cover. I can't pass a dive shop without going in, and always come out with something (for my husband, of course).
I hide Diver when it arrives until I have had the chance to read it back to front, before reluctantly handing it over to my drooling husband. I am green with envy when he takes off to Stoney Cove at the weekends and I have even tried all his gear on!
Why don't I dive? The thought of all that water above my head scares me rigid. Perhaps one day I'll pluck up courage and take the plunge, but until that day Diver gives me all the adrenaline rush I need. I will definitely subscribe again (for my husband, of course!).
Marion Hudson, Sheffield
Blood and thunder
I was surprised at the "blood and thunder" reporting style adopted in the coverage of Clive Soley's visit to the Goodwins (Labour Party Chairman Gets Rough UK Wreck-Diving Baptism, News, September).
The "fearless" reporter's version of events did not exactly gell with other accounts, but obviously poetic licence has to be allowed for!
Those who know Seadive will be aware that we work to particularly tight code-of-practice standards in all aspects of our programmed research diving. However, Clive's visit was a one-off guided and dive instructor-escorted visit, arranged on request for a qualified diver-politician seeking a better understanding of difficulties associated with heritage survey diving in an area such as the Goodwins.
Could the visit have been handled better? In a word, yes, of course it could! Everyone, including Seadive, benefits from hindsight and you can be sure that all and any lessons learned have already been incorporated into our policies covering escorted diver visits, including media coverage!
For those whose nerves lasted out the entire high drama of the "Clive's Baptism" story, I'm delighted to confirm that Clive actually survived. In fact evidently thrived, since he has begun knocking on appropriate Government doors in support of maritime heritage.
In case, among the foam and flurry of the report, you missed the point of his visit, it was aimed at drawing his and other politicians' attention to the present disparity between Government funding of land heritage as against underwater heritage, and its downside effect on protected wrecksite needs.
Seadive is very grateful to Clive for his efforts on behalf of heritage diving. Anyone genuinely interested in supporting it, why not link in with us through our website, www.seadive.org?
Norman Temple, Seadive Organisation, Ramsgate
Having just read the article Tricky Situations (August), I was very pleased to see the self-check golden rule of "Stop, Think, Act". We use something similar in the power-generation business, where a wrong action can have a catastrophic effect. However, we add a fourth step, "Review", to make the "STAR" principle of working.
The review is an important step, allowing us to establish that the action we have taken is the correct one, or whether the procedure or equipment can be improved in any way.
John Liddiard's advice was very sound, and such an approach will improve any individual's standard of diving and equipment. Perhaps we should think about including such thinking in our training schemes.
On a lighter note, I thoroughly enjoyed Andy Blackford's column on hazardous sports (Danger in the Darkness). I laughed until I cried as I unfortunately recognised myself as the caver described. It's not true about the lack of flora or fauna underground. On several occasions I have found frogs, spiders and even a rabbit!
Alison Fuller-Shaper, Kelso
Casting the first stone
I have just read the letter Smoke Rings (Off-Gassing, September). I wholeheartedly sympathise with Deb Pople's problem with divers' smoking, but does she drive a car?
Does she use fossil-fuelled public transport, the bane of asthmatics or, worse still, have the electricity which is supplied to her abode generated through nuclear means? When she can honestly say that nothing she does in her daily life adversely affects the health or well-being of anyone else, only then can she start dictating the actions of anybody else.
Did Ms Pople use air transport to reach her far-flung diving destination and, if so, during take-off, did she whisper an abject apology to all those people unfortunate enough to be underneath it as it dumped gallons of unburnt jet fuel into the atmosphere while labouring skywards?
I smoke and drive a 2 litre fuel-injected car, though I never touch alcohol before I get behind the wheel. That's a personal decision.
My suggestion to Ms Pople is this: deal with the modern world. And if she manages to get through one day without being a nuisance to anyone, I'd love to hear the secret. She might be able to do it if she lies comatose in a corner, but there will still be someone out there who'll accuse her of littering.
Tom Cummin, Tenerife, Canary Isles
On behalf of survivors
My father served on and survived the sinking of HMS Repulse. Readers might recall that the Prince of Wales and Repulse Survivors Association has requested designation for the ships under the 1986 Protection of Military Remains Act (PMRA). I have been actively supporting this request, while assuring diving organisations responsible for adoption of the divers' code of practice that we do not want to curtail all dives on these vessels.
I believe we are now moving together slowly, but surely the comments of Phil Butterworth (Why I Love Wrecks, Off-Gassing, September) have not assisted. Not surprising when he feels compelled to justify his self-confessed pillaging of undersea sites by drawing ill-founded comparisons between divers visiting underwater sites of naval remains, and land-based war cemeteries. Is it not an offence to remove anything from a land-based cemetery?
Our association recently learnt that there is no such definition as an "undersea war grave". The Admiralty views vessels such as Prince of Wales and Repulse as "derelicts". This has been the main driving force behind our campaign. We are committed to ensuring that proper respect is shown to the 840 men lost.
Mr Butterworth claims that "most casualties in wartime sinkings probably did not occur as a result of men going down with their ships, but from failing to be picked up afterwards". Can he tell me how many men from Repulse died in such a manner, as the ship took less than four minutes to sink? Does he know how many men were still trapped within this immense vessel as she sank? Or how many were trapped inside Prince of Wales when this 35,000 ton warship capsized?
Whilst accepting the comparison drawn between archaeological factors surrounding the Mary Rose and removal of items from undersea sites (derelicts), I should like to make an offer to this self-proclaimed guardian of our naval legacy. Mr Butterworth, if within your collection of artefacts you have items taken from British warships lost during either war, please inform me exactly what you have obtained, and from which vessel. I shall immediately inform the MoD on your behalf.
Mr Butterworths' comments are an insult to men lost in defence of our freedom, and their surviving relatives. Our association is set to give its blessing to a dive on the ships sometime next year, provided he is not one of the party. Mr Butterworth is the best possible advert for all that is wrong within the diving world and his callous attitude could easily damage much of the good work done by people who care for their sport.
The sooner he leaves a sport he professes to love, the sooner relations between divers and associations such as ours will flourish.
Alan Matthews, Wrexham
More thoughts from Saudi
As an expat woman living, working and scuba-diving in Saudi Arabia, I read your article on diving in Saudi Arabia (Open Sesame!, July) with interest. The issue of tourism in Saudi fills many expat divers with mixed emotions. A sustainable dive industry would have positive spin-off effects such as better-equipped dive boats and perhaps availability of trimix.
The downside is having to share pristine reefs and the possibility of being penalised for any inappropriate behaviour exhibited by dive tourists. Clampdowns on diving by the Coastguard often occur because of real or imagined infraction of the laws, so I hope Greg left the "casually picked-up brass porthole" at the Boiler wreck. The Coastguard takes a dim view of souvenirs, and dive bags are often searched on return to port.
I must clear up some misconceptions regarding women in Saudi Arabia, especially as John Bantin's inferences might scare off women divers. In five years, I have never experienced any problems and have always been treated with the utmost courtesy.
It is true that I cannot drive and that discrimination and other issues at times drive me crazy. Covered from head to foot in a black nylon abaya in 48íC temperatures and clammy humidity while the men lounge about in shorts is not my idea of fair. However, I can safely speak for the many expatriate women who work here in saying that we are in no danger of losing our identity.
Please keep the reporting objective, and do not fuel those myths that prevent women enjoying some truly excellent diving.
Mieke Busman, Riyadh, Saudi Arabia
I was very pleased to come across your coverage of Peter Benchley's work for the campaign to save sharks (Jaws Author Backs WildAid Campaign to Save Sharks, News, September). He has devoted much time and hard travel to that end. Soon after the movie Jaws hit the screen I was frequently asked by guests at my film lectures "Don't you think Benchley has done the public a disservice by introducing such a shark scare?"
My reply was that Peter had nothing to feel guilty about. His business and skill was in writing scary novels, Spielberg's was in producing them on screen. The onus must be on an educated public to know the difference between a documentary and fictional production. Scary films and books are big business.
I am now involved with the Princeton Shark Research Institute, which is focusing on building a consensus for the whale shark, which is being hunted to extinction. The institute has raised funds to place satellite tags on whale sharks in different parts of the world, to learn more about their movements and develop patterns of protection for them by third world governments that allow unrestricted hunting.
Anyone interested in learning more should visit www.sharks.org. The institute is doing fine work for a good cause.
Stanton Waterman, Lawrenceville, NJ, USA
Hand in glove
I was interested in Louise Trewavas's article We Stop at Nothing (September), as my own experience is very fresh in both my mind and body.
Halfway through a two-week holiday in Egypt, I encountered a patch of coral while emerging, Ursula Andress-like, onto the beach after a shore dive along the coast at Sharm Abu Dabur. A wave knocked me off balance so that I had to steady myself - a very painful wrong move, resulting in a deep cut in the palm of my hand. The dive guide deftly bandaged it while the other divers muttered: "That's the end of your diving for this stay!"
I was not going to be defeated that easily. Back at the camp, we devised a plan to keep my hand dry. I had some surgical gloves in my medical kit, and better still was that waterproof surgical tape was available to seal onto the glove and my wrist.
The result was that I could still dive with no leakage problems and no worries other than having one very hot, sweaty hand.
It certainly provided a good talking point - but I must remember the condoms next time.
Gwen Walker, Sherburn, Co Durham
Watch your wheels
I have noticed some serious slagging-off about Stoney Cove's time for air fills. On all my trips to the Cove I have waited no longer than 45 minutes for a fill, even on Sundays.
However I do have one complaint, and that's about the prats who take more then one space by parking over white lines. I know you need space to kit up, but if everybody else can do it inside the marked bays, why the hell can't you?
Good mag and keep up the good work!
A Smith, Worksop