Proper weighting to prevent SWB

[cliffgollus]

There are several current forum discussions dealing with SWB and SAMBA both in the general freediving section and also under techniques and training. Obviously a lot of people are thinking about these things!

Question: The importance of weighting so as to be positively bouyant within 20 feet of the surface is well established, but; if I carefully adjust my weight before diving while wearing a wetsuit, it can take quite a bit of weight ( 2 piece, 3mm suit, about 12 lbs). Once I dive and the suit compresses, air is driven out, etc, the suit does not give the same bouyancy at the surface, meaning I need to drop some weight. Is this something one learns from experience, are people doing a couple of dives and then re-adjusting their weight? Also, just because one is positively bouyant at the surface does not mean they are positive at 20 feet, what is the best way to determine this if you are not using a computer or depth gauge?

One last thing, I bought the Terry Maas book Bluewater Hunting and Freediving, and while the pictures are beautiful, etc, I am disapointed in the meager amount of technical freediving information dealing with things like training, weighting, etc. Can someone recommend a better book?

thx, Cliff

 

[unirdna]

Trial and Error

Hi Cliff,

Yeah, I have Maas's book too. It's a nice read, but isn't very technically robust; nevertheless, it is the best published piece of technical freediving literature I've read. Unfortunately, IMHO most of the published freediving lit is fluffy "one-with-nature" jive. All good if that's your bag, but I prefer, as Joe Friday says, "Just the facts ma'am". If Eric Fattah ever publishes all of his freediving info into a hardcover, I'll be the first one in line at the book store. After the lawyers get their hands on it, it'd be worth reading just for the disclaimers .

It sounds like the bubbles in your neoprene aren't reinflating after ascent. No, "reinflate" isn't the right word to use here. Since the air bubbles in neoprene are contained within the rubber, there is not deflation or inflation to speak of. If your suit is, infact, becoming less buoyant after a dive it must be that the bubbles are collapsing, and then failing to recover. This would mean that the same amount of air is still in your suit, but since the air is compressed, there is less water displacement, and thus less buoyancy. I've heard of this, but in all cases, the bubbles never recovered from the compression (which the bubbles in your suit must be doing if the suit regains its original buoyancy by the your next dive).

I have never owned a suit that did this. I have, however, experienced something similar to what you are talking about. But in my case, it was caused by lung volume, not my neoprene. When I would relax on the surface (just chillin' - not breathing up for a dive), my normal-breathing lung volume would be so low that my snorkel (which is cut off, and very short) would bob below the surface at times. A minor breathing adjustment took care of the problem.

Maybe this is what you're doing.....or maybe you just need a new suit .

Ted

edit: ...or maybe Jon's got this one licked .

 

[Jon]

Check out the IANTD "Advanced Freediving Manual".

I use a depth gauge or a marked rope to make sure that I am neutral at 33'- unless I am spearfishing with Ted.

It sounds like you might have air trapped in your suit if it only takes a dive or two to squeeze it out and you become more negative.

Wetsuits loose their bouyancy over time, but it takes hundreds of dives to do it. Next time you go diving play around with some ascents and descents to work all of the air bubbles out of your suit. Then, go weight yourself at 33' so that you are neutral at 33'. This will make you positive above that.

Jon

 

[derelictp]

Book

Hello!

The best book (about advanced freediving) I know is "Mastering breath-hold diving" written by J.G Neal. I think you can find it on NAUI:s homepage.

Unfortunately there is not so many books available about advanced freediving. (As far as I know)

 

[Jon]

I have the NAUI book ,by Jan Neal, as well.

I found the IANTD book to be newer and more up to date. It also has more useful info on proper weighting and other things.

Jut my $0.02

Jon

 

[derelictp]

Where did you buy it Jon (IANTD book)?

It would be interesting reading I guess!

 

[Jon]

I ordered it from a local IANTD dive shop. You can order it right from their headquarters in Florida.

The book is almost exactly the same as the one I got when I took Kirk's clinic.

Jon