Are you overweight
Yes, it is a personal question, and these two probably arent. But did you know that, for every unnecessary kilogram of weight you add to your belt just to be on the safe side, you can use up 10% of your gas supply in compensation Anne-Marie Kitchen-Wheeler wants us all to become weight-watchers

DO YOU WATCH YOUR WEIGHT Im not talking about over-indulgence in food and expanded waistlines here. The only over-indulgence that concerns me here is in helping yourself to too much lead from the weights box.
     But before you turn the page, thinking that this is an article for novice divers, read the following list of symptoms and see if any of them apply to you:

  • Head-up, feet-down position in the water (can vary from very slight to exaggerated!)
  • Deflate jacket on surface and you start to sink immediately, even with a lungful of air
  • Putting air in your BC as shallow as 5 or 6m to achieve neutral buoyancy (training dives excluded)
  • Wearing an extra kilo just in case
  • Constantly finning
  • Having trouble adjusting your buoyancy on ascent.
If you can relate to any of the above, you will probably find that you use more air than your buddy or other divers with you.
     Even if you dont, just consider this: for every kilo you dive overweight, you have to put a litre of air into your BC to compensate.
     That extra litre, put into your BC or drysuit at 30m to achieve neutral buoyancy, on ascent becomes 2 litres of air at 10m and 4 litres by the time you reach the surface.
     If, as many divers are, you are 4kg overweight, the additional 4 litres of air required at 30m to achieve neutral buoyancy becomes 8 litres at 10m and 16 litres at the surface. No wonder so many divers spend a lot of time on ascent getting air out of their BCs and drysuits!
     This obviously also creates real potential for a buoyant ascent. Does anyones drysuit vent as quickly as they would like
     Believe me, I have heard every excuse for a diver needing the additional weight, from Ive got big lungs/bones/build to my ears are bad and I need the extra to help me get down.
     In the latter case, the extra weighting is a potential cause of an ear/sinus barotrauma and potential perforated ear, torn sinus etc as you descend too quickly, worrying about ear-clearing rather than watching your depth!
     I met a fairly novice lady diver who told me before we dived that she had problems equalising and would probably take a long time to descend.
     I noted that she was wearing 6kg with a 3mm suit and told her that she would probably be happier with a couple less kilos, but she told me that she needed the extra weight or she would not get down at all. She said she was used to it.
     I accompanied her during her check dive to see how she got on. As soon as she deflated her BC, she started to descend. She used a Valsava manoeuvre to equalise but started to feel pain at about 2m and signalled to me as such. I realised that she was not controlling her descent, stopped her descending further and took her up slowly to allow her ears to re-equalise.
     Back on the surface, I said that she should drop the 2kg as I suggested and that I would help her descend if necessary.
     We tried again, and this time she just slipped under the surface and started to descend very slowly. She was able to stop 1m below the surface through breath control and equalised successfully. We then continued our slow descent. After a few dives she was able to descend at a similar rate to other divers. She didnt have an equalising problem à she was simply over-weighted!
     Everybody is different, and every different body shape and size requires different weighting. I know a very petite dive instructor who dives in a 5mm suit and wears no lead at all (with an aluminium tank!) and I know a 17 stone, six-foot-two guy who wears only 2kg.
     There will be other divers of similar build who need an additional 2 or 3kg above these to achieve proper buoyancy.
     I get concerned when I see petite women in Lycra or 3mm suits diving with 7kg, and so used to being over-weighted that they dont bother with a weight-check, or to ask why less experienced divers than they are surfacing 20 minutes after them.
     If you are wearing a two-piece wetsuit or a drysuit you will obviously require more weight, but I have still seen divers of similar build and kit configuration wearing twice as much as their buddy.

perform your own weight check
I heard of a trainee diver who allowed her partner, a dive leader, to set her weight system up. She had 4kg in each of the integrated weight system pockets, which her instructor was rather concerned about, but she and her partner insisted that she was happier with the extra weight for skills sessions, so the instructor allowed it.
     Unbeknown to the instructor, another 4kg had been stuffed into her BC pockets! The poor diver was struggling to keep buoyant on the surface, and it took 12 breaths to inflate her BC to complete the fin-pivot skill. She completed her course with 6kg of weight, which was half what she started with but still probably 2kg more than she really needed.
     Diving underweighted can lead to buoyant ascents at the end of the dive, so I am not advocating that everyone knocks a couple of kilos off the next time they dive. In fact underweighting is comparatively rare. A diver who starts off with too little weight will have difficulty descending, though I do know of cases in which the diver has continued with the dive in such circumstances.
     On a boat dive in the English Channel, a diver swam down very fast and didnt even realise that he had left his weightbelt on the boat until he hit the bottom. He hung onto a lobster pot for a couple of minutes until he realised his predicament, and made his ascent as slowly as he could.
     Luckily he didnt spend too long at depth and was OK. Diving underweighted is potentially very dangerous if it causes a buoyant ascent towards the end of a dive. All the more reason for being correctly weighted.
     Next time you go diving, conduct a proper weighting check. At the start of the dive and with all your equipment in place, take a normal breath from your regulator and empty your BC. You should float at eye level and start to sink only when you start to breathe out.
     Do this again at the end of the dive. You will be more buoyant, so will float higher with a full breath of air, but you should still start to sink when you breathe out, so breathe out slowly to a count of 10 and you should have long enough just to slip below the surface. If you can do all this, you are correctly weighted.
     If you are on an extended dive trip, check your weighting every few days, as your kit will become less buoyant and you will become more waterfit. Most divers can shed a kilogram or two over a fortnights diving and often find they never have to use the higher amount again.

where you put your weights makes a difference!
If you are used to diving with steel tanks and find yourself using an aluminium tank, try putting a kilo weight on the tank-band instead of on your weightbelt. Remember that if you swap from using a steel to an aluminium tank you will need up to 3kg extra weight to achieve the same level of buoyancy.
     This varies depending on the shape and size of tanks, so always perform a weighting check when you dive with a different set-up or in a different environment. Dont forget that seas vary greatly in salinity, and what you wore in Hurghada is not what you should wear in the Bahamas.
     If you have floaty feet, spread your weights by using some ankle weights, or look at where your weightbelt sits. Many women complain of the floaty feet phenomenon. This may be simply because their waists are higher up than mens, and push the centre of gravity higher up, causing them to tip forwards.
     Unfortunately, I have seen this before now misdiagnosed as underweighted and an extra couple of kilos are added until they are forced to swim in the classic heads-up feet-down position because they are now overweighted.
     Ladies, try wearing your weightbelt hip-slung (very trendy) or at least a little bit pushed down on your waist.
     A rubber weightbelt, as worn by spear-fishers and free-divers, will stay put comfortably on your hips and still conforms to quick-release standards.
     Integrated weight systems may be good too (they tend to sit on your hips rather than your waist) and are a very good reason to ensure correct weighting, as most systems work best with less weight!
     From experience, I estimate that for every extra kilo, a diver uses 10% of their air supply in compensation. So if you can shed a couple of kilos you will either extend your bottom time, or increase the safety margin in your diving because you absorb less nitrogen. Do you need any more motivation Perform that weight check next time you go diving.
     If you are always the first back from the dive, you have nothing to lose and the most to gain!

If properly weighted, with an empty BC and a lungful of air the diver should float at eye level.
If he breathes out, he should slowly descend.
Correctly weighted divers relaxing and saving their air

Start a Forum discussion on this topic