Cold water free diving...

[scubakat]

Hi all, I am in my second week of divemaster training and I need some help. One of the skills we have to perform in open water is a free dive to 30fsw. In the Puget Sound the water temp is about 44-degrees-F and I will be wearing a drysuit (if it's back from the shop) or a 7mm 2-pc wetsuit. I have never done a free dive to 30fsw in warm OR cold water and I am a little (ok A LOT) nervous!

I know that I will need to wear some weight on a belt but I have no idea how much (for drysuit OR wetsuit).

I know that my surface dive technique is good (at least it is in the pool) but I am worried about having too much weight & suit compression (or drysuit squeeze) & not being able to kick back up.

Do y'all have any ideas on technique or weighting? Is this a hairbrained idea? Does anyone do cold-water free diving regularly?

thanks!!
Kate

 

[Paul168341]

Kate,
What agency is requiring this?
If that's what you gotta do, then forget the drysuit for this. Use your wetsuit and enough weight to be neutrally buoyant. That way you don't have to worry about squeeze. I can't imagine this skill taking too long so you'll only have to bear with the cold for a short while. I'm still amazed that they're requiring a 30fsw freedive.

 

[jan]

Hi Kate
for freediving you should weight yourself so that you are neutral bouyant at 15'. meaning you will float at the surface. take no more than three deep breaths before going down. when decending lie on the surface looking down , lift one leg up, point one or both hands towards the bottom . when your fins clear the surface give two or three kicks keep your arms extended over your head with your hands together or your arms at your side you should be able to glide to 30' using no effort this will lower your heart rate conserving your air at a relaxed state and leaving you plenty of air to race back to the surface . when surfacing keep your hands at your side or over your head again keeping your profile as small as posible reducing drag.
Its not as hard as it sounds to help you might want to start shallow and work your way down. this will help you build up some confidence.
Good Luck
Jan

 

[GeekDiver]

I don’t have any experience in freediving but Diver Training Mag had a big section on it last month. They talked about an exercise called Pull Downs. This is where you pull your self down an anchored rope with your arms and not using your legs to swim down. This is supposed to help build stamina, conserve energy, and build confidence. You might want to try and pick up a copy from a library or book store, the article was very informative and listed several resources on freediving.

Good luck,
GD

 

[scubakat]

Paul: It's the YMCA. The free dive is not a requirement for divemaster in the YMCA Standards & Procedures. It's an added skill by my instructor. He's requiring us to meet the YMCA Gold Master Diver skills assesment.

Jan: Thank you very much for the tips! I like the gliding idea.

Geek: I will go find a copy. Is it March or April?

thanks again!

-Kate

 

[GeekDiver]

ScubaKat

I think March but not sure when I get home I'll check on it and see If I can post some of the online ref they listed.

GD

 

[rcohn]

What Jan said is on target. You might need a few more kicks with a 7 mm wetsuit and I would probably use a two leg surface dive if you aren't familiar with the one leg variety. Two legs will give a bit more driving force, which is helpful with a 7 mm suit.

You will only need the 7 mm wetsuit, you stay much warmer when freediving because over 50% of your time is on the surface with no wetsuit compression.

Breath-hold times increase after a few dives, divers don't usually reach their peak performance without at least 15 minutes of diving. Therefore, don't try to do the 30 ft on your first dive, do a few shallower dives first to warm up. This will also give you the chance to adjust your weights.

Also, I find it very difficult to get good breath holds in really cold water, other freedivers I know have said the same thing. You just seem to feel the urge to breathe sooner, so be prepared for that. I don't know what the visibility is like there, but if you have only been freediving in pools or warm tropical water where you can see the bottom, it may be different. You get used to diving in lower visibility where you can't see where you're going until you get there, but it may be a psychological barrier at first.

The comfort level rapidly improves with practice, you get used to freediving to 30 ft in cold, low vis water but it may take a few dives to get over the psychological barriers. If you can, try to go out once with a buddy before this test for a little practice, even some shallow freediving will be a big help.

Good luck.

Ralph

 

[Scottri]

Hello from another PNW Puget Sound cold water diver! I demonstrate free diving up here from time to time and I would suggest a wet suit for that skill with about 15 pounds of weight (that is the positive bouyancy of your suit). If you have to do it in a shell style dry suit try about 8 to 10 pounds. The biggest problem is the first 15 feet. Once you get below that point it's not so bad. I would suggest a quick surface swim with a quick bend into the pike position and kick like hell. If you just turn and go down from the surface with no momentum you won't get down but you will provide some good laughs for the people watching.



Scott

 

[GeekDiver]

ScubaKat

Dive Training Mag. March 2002 pgs 28-39

Online ref:
www.freediver.co.uk
www.divetech.com

Regards,
GD

 

[jrtonkin]

44-deg water? Cool, but not intolerable in a 2x7mm wetsuit, especially if you keep moving.

Some tips...

Don't try to do this dive straight off the boat. Get in and moving a bit. Two reasons, first warm muscles are much more responsive (and having your circulation up a bit means more 02 in your blood, so you'll feel less strain from the breath-holding). Second, the shock of going into cold water tends to cause you to exhale (don't know why, just know its's true). Moving around a bit first gives the water inside your suit a chance to warm up.

A 2x7mm wetsuit has about 10lbs of positive bouyancy at the surface (at least for me. 5'8" male, reasonably fit). I'm guessing it'll probably be down to about 3-5 lbs at 30'. Drysuits I have no clue about.

Because you're not going to be breathing compressed air to counteract water pressure, your body will also compress slightly. For me, I go through about a 2 lb change (from +.5 to -1.5) over the first 15', and guess I'd probably get another 1 lb off the next 15'.

So you're looking at a total swing of close to 8 lb from surface to depth.

As for how much weight, it depends on where you want to be neutral. If you're neutral at the surface, it'll be easier to get down to depth, but harder to stop at 30' and make the swim to the surface. If you're neutral at depth, then the swim down will be harder, but it'll be easier to not overshoot the mark by too much, and the swim up will be nice and easy.

If it was me doing it, I'd go for neutral or even
slightly negative at the surface. This makes for a nice easy descent, so when I get to depth, I'd still feel like I had a lot of 02 in my lungs.

This is largely psychological though. I have to work hard to get myself back to the surface, but that's what I'm going to want to do anyways, rather than having to work hard to take myself away from the surface, which would tend to make me want to give up only part-way down.

You're going to be descending a lot faster than you probably do normally, so be prepared to clear your ears quickly and often. Also because you're not breathing compressed air it'll probably be necessary to clear them at shallower depths than you're used to.

In general, practice swimming lengths underwater... 30' deep means 60' of swimming, which is most of a length of most pools. Also find the deepest pool you can (most pools with 10m diving platforms are 15-18' deep) and spend time just sitting on the bottom of the deep end, or fetching one of the 10lb diving bricks (or your weight belt) from the bottom. All told figure this will take at least 5-10 sec for the descent, 5 to stop and turn around, and 10-20 sec for the ascent. So you're looking at holding your breath for up to 35 sec.

Jamie