Problems trimming out

[Superlyte27]

So the problem wasn't getting down, but rather getting down in proper trim. Okay, I get that.

I've never met a single cave instructor who tested buoyancy with 500psi in the tanks. Probably because most cave dives round these parts end with quite a bit more gas in the tanks than that.

At any rate, when I was diving LP95's it required 4lbs to the bottom bolt to trim me perfectly. But, I'd rather switch to LP104's than add 4lbs of of lead. I made the switch and never looked back.

 

[PfcAJ]

If you are positive with empty tanks, you're gunna have a bad time.

That **** almost killed Sheck, and the same could happen to anyone who doesn't do a proper weight check. Being light, post emergency, low on gas, and struggling to keep of the ceiling could end in disaster.

I wear an 8lb vweight with 104s and a 400g thinsulate (and so do a lot of my friends). If anyone tells you that you don't need extra weight when you tested for it, tell em to bugger off.

 

[TSandM]

In my Full Cave class in Mexico, my instructor and I did a 44 minute air-sharing lights-out exit through a couple of minor restrictions. By the time I got to open water, I had about 600 psi in my tanks. We did our "deco stop" with me swimming downward the entire time. It had happened that morning that I could not put together the weight I knew I needed for the double 80's, and I had to settle for less. I got a good object lesson in how uncomfortable that is -- and when we surfaced, I said to the instructor, "That was miserable -- I really needed those extra four pounds!" And he said, "If you hadn't said that, I was really going to worry about you. You sure weren't the diver I saw yesterday!"

 

[Pegger]

I had that problem with my double LP72s.

To compensate, I added a 4 lb "dingleberry" and Hollis F1 fins.

Tell me what a dingleberry is please.
I'm wearing a Pinnacle Evolution 2 suit with their heavy Merano wool undergarments, turtle fins and a SS plate. The only thing I don't have on for the pool is a hood and dry gloves. With 500 psi in the tanks.

Steve

---------- Post added April 23rd, 2013 at 10:37 AM ----------

What type of suit + undergarment are you wearing?
What type of backplate?
What fins?

If you are using this setup in the Great Lakes "no lead" is either minus any substantive undergarment or rediculously underweighted.

I'm not sure I understand your statement.

 

[TSandM]

I think what Richard is trying to say is that, if you are wearing enough undergarment to stay warm in deep Great Lakes temperatures, you absolutely will need more weight than an empty set of tanks and a steel plate can provide.

The second session I moved the tanks down as far as i could on the bands, wore a canister light and a 6 lb argon bottle and didn't need any weight to sink me but my feet were still light.

This comment suggests that you felt you were properly weighted with no weight, which seems very unlikely.

 

[rjack321]

I've never met a single cave instructor who tested buoyancy with 500psi in the tanks. Probably because most cave dives round these parts end with quite a bit more gas in the tanks than that.

They are lazy and wrong. Like PfcAJ, I need about 9lbs with 104s in my drysuit in FL with a somewhat tired 200gm thinsulate undergarment + shell suit. In MX I need about 17lbs with AL80s in the same suit & undergarment. Up here in BC caves (46-50F freshwater) with double 85s or hp100s, I wear a much thicker undergarment (weezle extreme+), a CF200 suit, a 5lb steel plate, and I need 14 lbs of lead. Same rig in saltwater requires 22lbs.

That's to stay off the ceiling when the tanks are way into my reserve, if I ever dip down into that gas the last thing I need is more stress and a still higher consumption fighting to stay down.

I can't believe the OP is suitably dressed for Great Lakes water temps and needs no lead with double 95s.

 

[Pegger]

I can't believe the OP is suitably dressed for Great Lakes water temps and needs no lead with double 95s.[/QUOTE]

I didn't post this thread to debate how much lead it took to sink me, i posted to see if anyone had any suggestions for trimming out properly without using ankle weights.

 

[TSandM]

Well, I don't have any suggestions about how to trim out underweighted . . .

Trimming out is very simple. It starts with posture, and then physically balancing the gear. If your gear is head-heavy, as 95s are (severely), you HAVE to move some weight down on your rig or your body to balance that. If you have no room for any additional weight (as someone, for example, diving 95s in very warm water) then you need different tanks.

Options for moving weight down include dropping the tanks in the bands, lengthening the shoulder straps and tightening the crotch strap, or adding weight to the bottom bolt, your waist (if your waist is low enough in the whole picture -- mine isn't) a weight harness, your dry suit pockets, heavy negative fins, or ankle weights. Options for moving lift up are using the bottom hole on your wing, using a wing with a wider upper arc, or parking air in your dry suit shoulders or arms.

Some combinations of diver, exposure protection and tanks don't work. Bob Sherwood spent an hour in the water with me with our LP72s, and concluded I was right -- I CAN'T trim out in them. 95s are particularly difficult, because they are really heavy at the top.

 

[rjack321]

I didn't post this thread to debate how much lead it took to sink me, i posted to see if anyone had any suggestions for trimming out properly without using ankle weights.

Who cares if you can or can't trim out right now? You shouldn't be diving underweighted - period. Once you get the total mass of lead right, then we can talk about moving lighter vs heavier things around to achieve proper trim. You are so drastically underweighted there's nothing to move or change right now anyway.

 

[Superlyte27]

They are lazy and wrong. Like PfcAJ, I need about 9lbs with 104s in my drysuit in FL with a somewhat tired 200gm thinsulate undergarment + shell suit. In MX I need about 17lbs with AL80s in the same suit & undergarment. Up here in BC caves (46-50F freshwater) with double 85s or hp100s, I wear a much thicker undergarment (weezle extreme+), a CF200 suit, a 5lb steel plate, and I need 14 lbs of lead. Same rig in saltwater requires 22lbs.

That's to stay off the ceiling when the tanks are way into my reserve, if I ever dip down into that gas the last thing I need is more stress and a still higher consumption fighting to stay down.

I can't believe the OP is suitably dressed for Great Lakes water temps and needs no lead with double 95s.

That's kinda funny. Here in the caves of FL, I don't know of a single cave diver adding weight to their LP104's. The diver is probably already negative about 20lbs without adding any weight in a drysuit.

I will poll 100% of the divers I see at Ginnie for the next month though and report back. I'll be shocked if I find a single person with 104's wearing weight. We should have about 50+ people to use for this research.