Cold water Wing lift - again

[cool_hardware52]

This thing that you should always strive to minimize weight, preferably to the extreme, must have been invented by wetsuit divers.

Excess Weight kills, again I would refer you to accident reports that all too often include overweighted divers.

Excess weight makes buoyancy more difficult.

The vast majority of divers use wetsuits, not drysuits.

Drysuit divers also have a form of redundant buoyancy that wetsuit divers lack, making the consequences of a single failure less threatening.

Tobin

 

[decompression]

Excess Weight kills, again I would refer you to accident reports that all too often include overweighted divers.

Excess weight makes buoyancy more difficult.

The vast majority of divers use wetsuits, not drysuits.

Drysuit divers also have a form of redundant buoyancy that wetsuit divers lack, making the consequences of a single failure less threatening.

Tobin

Why don't people get this?


Sent from my iPhone using Tapatalk

 

[Storker]

Excess Weight kills

What's "excess weight"?

I claim that if a drysuit diver carries so little weight that they can't loft their undergarments enough to keep warm and are shrink-wrapped at their safety stop, they might be correctly weighted for warm water, but they're definitely underweighted for the temperature they're diving in. A few kilos more than that is not excessively weighted, it's correctly weighted for the conditions. In the warm season when the water is a balmy 10-15C, I weigh myself to be somewhat shrink-wrapped at my safety stop with an empty wing. In the cold season when the water temp is in the single digits (C), even the low single digits, I like to add at least a couple of kilos to stay warm. I'm still alive.

And to be completely explicit here, note that I'm talking only about the type of diving I've got a half-decent experience in: Drysuit diving in cold water. Whatever is "right" for wetsuit diving in more temperate conditions is something I won't claim that I know much about.

I would refer you to accident reports that all too often include overweighted divers.

How overweighted? Are we talking about some 1-3 kg above the bare minimum to sink them, or are we talking about excessively overweighted? If the former, I and most of my buddies should have been dead a long time ago. If the latter, we agree.

 

[dmaziuk]

But I would be using a very high tech heated wetsuit...the entire wetsuit heated, powered by a Can light style battery.

Mmmyeesss... underwater, wrapped in ligthbulb filament, carrying a battery big enough to heat it up... what could possibly go wrong.

 

[Storker]

 

[cool_hardware52]

What's "excess weight"?

More than required to hold a shallow stop with an empty tank.

What are the genuine risks for the wetsuit using recreational single tank diver and how do we prioritize them?

Slightly under weighted: OMG! they might have to conduct their shallow stop at 20 ft. and enjoy a slow ascent to the surface as their suit rebounds.

Over weighted slightly or otherwise: Requires energy to stay at the surface if : 1) The diver can't or won't ditch weight or 2) The diver can't or won't add gas to their BC. Eventually they will tire.

I'll pick # 1 every time. The risks are vanishingly small of any injury, and in the extremely unlikely event of DCS it can be treated. Dead OTOH is more difficult to treat.

Here is the bottom line for my recommendations for cold water single tank weighting; There is nothing the diver can do to his gear that will make him negative at the surface. Every action he might take will make him positive. Add gas to the BC, positive, drop ballast, positive, Breathe down their cylinder, positive. Pretty had for a panicked fatigued diver to screw that up.


Tobin

 

[danvolker]

Mmmyeesss... underwater, wrapped in ligthbulb filament, carrying a battery big enough to heat it up... what could possibly go wrong.

CONSIDERING we use them already, with low failure rates, and you have a wet plug you can unplug at any time....and you could also have a backup.....
And....considering there is FAR MORE that is likely to go wrong with a CCR Rebreather ( which most of you guys are not screaming foul about...) , I think this is a viable direction.

Worst case, I abort a dive.
No harm, no foul.

 

[Storker]

What are the genuine risks for the wetsuit using recreational single tank diver and how do we prioritize them?

I've been talking only about weighting for drysuit diving and how that may differ from weigthing for wetsuit diving. Why are you arguing about wetsuits?

And since this thread is about cold water wing sizing, the different weigthing strategies for wet vs dry suits should be relevant, since drysuits are pretty darned relevant for cold water diving, IMNSHO.

 

[danvolker]

I've been talking only about weighting for drysuit diving and how that may differ from weigthing for wetsuit diving. Why are you arguing about wetsuits?

And since this thread is about cold water wing sizing, the different weigthing strategies for wet vs dry suits should be relevant, since drysuits are pretty darned relevant for cold water diving, IMNSHO.

Pardon my ignorance ....but I thought you had been discussing the need for Dry suit divers to use very large amounts of weight, that could allow a great deal of air into the drysuit for better warmth ....and that this huge amount of weight could often SINK a BC or wing, unless it had massive lift potential.....Did I miss something?

 

[cool_hardware52]

I've been talking only about weighting for drysuit diving and how that may differ from weigthing for wetsuit diving. Why are you arguing about wetsuits?

Er, uh, well gee, the OP specifically listed a wetsuit in his original post.

While drysuits offer redundant buoyancy that a wetsuit lacks the concepts are also the same regarding weighting.

If a diver follows my recommendation for cold water single tank weighting, eye level at the surface with no gas in their wing and a full tank *even if they are using a drysuit* what is the typical net result?

Again drysuit undies compress, that means a diver at 15 ft in a "shrink wrapped" drysuit will be less buoyant that they were at the surface, with high loft undies they will be considerably less buoyant, but lets just focus on a diver using a 100 cuft cylinder and a drysuit that is 28 lbs positive at the surface.

In order for this diver to hold a 15 ft stop with an empty tank his suit would need to lose ~7.8 lbs (weight of the gas in a 100 cuft cylinder)

Is this reasonable? Will a suit that starts out +28 loose 8 lbs at 15 ft? IME the suit will lose at least this much. Don't believe me? Go try it.

Now before you start *another* rant about gas in your suit = warmth please note we have been able to maintain a shallow stop with a fully evacuated cylinder, i.e. empty, no more gas. This is the worst case scenario.

Most dives will end with 500-1000 psi. That means the weight of this gas, typically a couple lbs., allows for the diver to inflate their drysuit at their shallow stop.

If the odd day arrives and a diver needs to pull a vacuum on their tank at 15 ft they *might* have to snug up their suit for *OMG* *OH the Horror!* 3 minutes.........

BTW if you need to balloon your suit to be comfortable you may need better undies.

Tobin