Bouyancy Aids

I always thought the buoyancy from anything (incl. buoyancy aids) was not so much to do with the item itself but more the volume of water it displaces (less its own weight). Thus, for 50N buoyancy the thing has to be a certain volume - which means things then come down to where the volume is located and how it is spread around.
I don't like them that much myself and agree that there are some circumstances where they can be more dangerous than helpful. However, I assume somebody has looked at the advantages and disadvantages and the balance comes out in their favour.
Ian

Author	Message Share Topic Printable Version Delicious Digg Facebook Furl Google MySpace Newsvine reddit StumbleUpon Translate Twitter Windows Live Yahoo Bookmarks Topic Search Topic Options Post Reply Create New Topic
Deimos Send Private Message Find Member's Posts Newbie Joined: 08 Nov 06 Location: France Online Status: Offline Posts: 12	Post Options Post Reply Quote Deimos Report Post Quote Reply Topic: Bouyancy Aids Posted: 04 Feb 07 at 11:26am
	I always thought the buoyancy from anything (incl. buoyancy aids) was not so much to do with the item itself but more the volume of water it displaces (less its own weight). Thus, for 50N buoyancy the thing has to be a certain volume - which means things then come down to where the volume is located and how it is spread around. I don't like them that much myself and agree that there are some circumstances where they can be more dangerous than helpful. However, I assume somebody has looked at the advantages and disadvantages and the balance comes out in their favour. Ian

JimC Send Private Message Find Member's Posts Visit Member's Homepage Really should get out more Joined: 17 May 04 Location: United Kingdom Online Status: Offline Posts: 6662	Post Options Post Reply Quote JimC Report Post Quote Reply Posted: 04 Feb 07 at 5:27pm
	Guys, I recommend an experiment - try swimming in reasonably lumpy water for 5 minutes with and without a buoyancy aid. See how easy it is to avoid getting mouthfuls and/or nosefuls of sea water with and without. You'll then be in a position to evaluate whether they are useful or not. While you're at it you can also evaluate whether you float face up with your mouth and nose clear of the water without a buoyancy aid and might therefre be beter off without one... The reason why lifejackets are so very big and clumsy is because it requires a great deal of very carefully placed buoyancy to guarantee that you end up with face far enough clear of the water not to drown if unconscious. Such a large amount of buoyancy is impractical for dinghy racing. The reason for having a buoyancy aid is that the extra 50N of buoyancy makes a big difference in how easy it is to keep your face out of the water in waves. It means you spend a lot less energy in just stopping yourself drowning and so have it available to recover the boat. Edited by JimC

simsy Send Private Message Find Member's Posts Posting king Joined: 14 Jun 05 Location: United Kingdom Online Status: Offline Posts: 158	Post Options Post Reply Quote simsy Report Post Quote Reply Posted: 04 Feb 07 at 6:21pm
	I have had to agree with Jim on this one. I have had experience with both scenario's stated. A bouyancy aid might not make a big difference in light winds and fine weather, but when it gets breezey and you unexpectabley take a dip, you will be thankful. Why waste energy on trying to keep yourself afloat when it can be better used elsewhere? It certainly doesnt make you look anymore professional.

Villan Send Private Message Find Member's Posts Visit Member's Homepage Really should get out more Joined: 26 Nov 05 Location: United Kingdom Online Status: Offline Posts: 1768	Post Options Post Reply Quote Villan Report Post Quote Reply Posted: 04 Feb 07 at 6:30pm
	Anyone at the Tiger this weekend look at the A-Rater guys? I dont think I saw them wearing BA's!! Wasn't able to stick around for the prizegiving, But I heard it was bought to the Comitiees attention, so does anyone know what happened?
	Vareo - 149 "Secrets" TandyUK Servers

redback Send Private Message Find Member's Posts Visit Member's Homepage Really should get out more Joined: 16 Mar 04 Location: Tunbridge Wells Online Status: Offline Posts: 1502	Post Options Post Reply Quote redback Report Post Quote Reply Posted: 04 Feb 07 at 11:03pm
	I'm not advocating not wearing a bouyancy aid but I do feel the design is poor. What use a bouyancy aid which rides up the body so that most of it is out of the water? And I think it particularly bad if its bulk on the chest makes it difficult to climb onto the centreboard. I'd like to see a design which is disposed around the body such that it is completely emersed when the wearer is in the water and does not bulk out the chest making it difficult to climb onto the board. I haven't noticed any designers/manufacturers contribute to this forum.

Deimos Send Private Message Find Member's Posts Newbie Joined: 08 Nov 06 Location: France Online Status: Offline Posts: 12	Post Options Post Reply Quote Deimos Report Post Quote Reply Posted: 05 Feb 07 at 9:01am
	I remember many years ago when sub-aqua diving and dry suits were just starting to be used. People used to have to wear weights around their ankles due to the risks of the air moving inside them to your feet, turning you upside down then holding you upside down with "no way out" (and obvious consequences). I don't dive any more so don't know what happens these days but it does illustrate the importance of where the buoyancy is on your body. Ian

Skiffman Send Private Message Find Member's Posts Visit Member's Homepage Far too distracted from work Joined: 27 May 04 Location: United Kingdom Online Status: Offline Posts: 291	Post Options Post Reply Quote Skiffman Report Post Quote Reply Posted: 05 Feb 07 at 10:33am
	if you find it difficult to climb on the board then you have got the wrong bouancy aid or one that does not fit properly. The hardest part of climbing on to a board is to make sure you dont take a chunk out of it with your hook!! in 49ers most crews do not wear bouancy aids unless it is windy, especially in europe, aus and the usa. ISAF just states that you have to adequete personal bouancy how each crew member on board the boat and does not say that you have to wear a bouancy aid. It is up to class rules and the SI's of event to say that you have to wear a bouancy aid. At almost every UK event it will say you have to wear one but abroad they rarely do other than junior classes. Have you tried a magic marine skiff bouancy aid or racing bouancy aid?? Both do not ride up and are small compared to other makes. oh and in Higher and Faster that bit at the back of there harness is more likely to be heavy duty PVC or something to make the harness heavy (about 2.5kg)
	49er GBR5 teamfletcherandsign.co.uk Team Fletcher and Sign campaign site

Matt Jackson Send Private Message Find Member's Posts Really should get out more Joined: 21 Sep 04 Location: Darlington Online Status: Offline Posts: 962	Post Options Post Reply Quote Matt Jackson Report Post Quote Reply Posted: 05 Feb 07 at 4:58pm
	Can we PLEASE stop the discussion about wether it's sensible to wear BAs. It gives totally the wrong impression about them and leads to youngsters doing everything possible to avoid wearing them. I would much rather face the tiny risk and minor discomfort of wearing one than be constantly worried that my son has decided to sail without it because 'it looks a bit geeky'. In any case it's the rules in most locations/events, get over it. I am on the lookout for a slim BA myself because I often get stuck under the boom when tacking (the boom on a Contender can be quite low you know:-). The current trend does seem to be for really high cut ones. Can't really see from the photo but the Zhik one seems to be a thinner panel at the back is that right? Edited by Matt Jackson
	Laser 203001, Harrier (H+) 36

Pesmo Send Private Message Find Member's Posts Newbie Joined: 10 Oct 05 Location: United Kingdom Online Status: Offline Posts: 25	Post Options Post Reply Quote Pesmo Report Post Quote Reply Posted: 05 Feb 07 at 5:21pm
	Is a crotch strap viable on a BA to prevent it riding up ?

redback Send Private Message Find Member's Posts Visit Member's Homepage Really should get out more Joined: 16 Mar 04 Location: Tunbridge Wells Online Status: Offline Posts: 1502	Post Options Post Reply Quote redback Report Post Quote Reply Posted: 05 Feb 07 at 5:51pm
	Probably a good idea but decidedly naf looking on the current crop of bouyancy aids so unlikely to catch on. That's why bouyancy built into a harness would be good. Alternatively bouyancy which extends down to waist level could then be retained at that level by a belt.