UTD and Neoprene drysuits

[CAPTAIN SINBAD]

Hello:

I am wondering why does UTD not allow neoprene drysuits? I am quoting from the UTD website ...

"Dry suits should be constructed of a non-buoyancy changing type material. Neoprene suits (buoyancy changing) should not be considered for diving at any level simply due to bulkiness, variable buoyancy and thermal protection characteristics. The use of Neoprene as dry suit material causes the undesirable situation of ensuring that the diver is overweighed and has lost a certain percentage of thermal protection during the bottom portion of his dive. Being overweight on the bottom forces a diver to have too much air in the suit/BCD which can cause trim, drag and efficiency issues. Balanced suits on the other hand have minimal buoyancy-swing characteristics. The downside is that they as well offer little in the way of thermal protection. To over come this, some form of undergarment is necessary. (See section on undergarments.)"

This seems to be a very poor case for ruling out the use of neoprene suits. I have owned both shell suits and neoprene suits and I wear less lead in my neoprene suit than in shell. Neoprene needs less undergarment for the same temperature and can be stitched closer to the body due to its flexibility thus reducing the air-pocket.

Are these simply "recommendations" or are the UTD members / instructors obligated to comply by these "standards?"

Thanks -

 

[decompression]

The issue is with the buoyancy characteristic of neoprene. Either a neoprene wetsuit or drysuit (in general) will have changing buoyancy at depth which cannot be countered by the addition/subtraction of air. Where this comes into play is a failure at depth. With a balanced rig after suffering a wing failure, the diver begins to ascend. The expansion of air in the suit can be exhausted while the buoyancy of the suit returns creating a greater possibility of an uncontrolled ascent.

 

[Doppler]

... The expansion of air in the suit can be exhausted while the buoyancy of the suit returns creating a greater possibility of an uncontrolled ascent.

Thanks for the explanation... well put.

However, you don't believe this to be true do you? If so, has it been tested objectively; and where are the data? When was the last time whoever came up with this advice looked at a well-designed, well-fitting, modern neoprene suit... and dived with it? How many wing failures has the author of this "standard" suffered? Do we know? Must be a lot to come up with advice as dogmatic as this. Let's take a straw poll. I will go first. I've got a few thousand deco dives, about nine hundred cave dives and just under a thousand hours on rebreathers and I have had... ummm, hold on give me time to add them up... Yep, looks like ZERO wing failures. Perhaps because I inspect stuff before jumping in the water, maybe I have horseshoes up my arse.

One can generalize about many issues... for example, most trilaminate suits are less well-fitting than a neoprene suit and therefore create greater drag... which is a factor on ALL dives not just in the unlikely event of a wing failure...

Not trying to be a prick but this type of directive is questionable at best. You and I both know that a lot of the equipment dogma spouted out by "agencies" in the past has come back to haunt them... Hell, I wrote a few articles telling people the personal dive computers had no place in technical diving... HA... look how that turned out!

 

[Rich Keller]

The issue is with the buoyancy characteristic of neoprene. Either a neoprene wetsuit or drysuit (in general) will have changing buoyancy at depth which cannot be countered by the addition/subtraction of air. Where this comes into play is a failure at depth. With a balanced rig after suffering a wing failure, the diver begins to ascend. The expansion of air in the suit can be exhausted while the buoyancy of the suit returns creating a greater possibility of an uncontrolled ascent.

This makes no sense. Why do you think suit compression can not be countered for by adding air to the BCD? Why do you think that after a wing failure the diver will begin to ascend? If you are weighted properly a neoprene suit should never be a problem. In the case of a BCD failure or an out of air emergency you want a neoprene suit that has buoyancy built into the material that can not be lost.

 

[decompression]

Yes, Steve, I know.....I know. Just answering a question.

---------- Post added November 13th, 2014 at 04:52 PM ----------

This makes no sense. Why do you think suit compression can not be countered for by adding air to the BCD? Why do you think that after a wing failure the diver will begin to ascend? If you are weighted properly a neoprene suit should never be a problem. In the case of a BCD failure or an out of air emergency you want a neoprene suit that has buoyancy built into the material that can not be lost.

Rich, well.....I think after a wing failure a prudent diver may want to end the dive. A neoprene suit, at depth has lost its buoyancy and its insulating properties. The draw back with a thick wetsuit at depth is a neutral diver at the beginning of a dive that had a wing failure now has to attempt to swim up with lead that had to neutral a thick wetsuit (20-25#?) or dump weights, where upon ascending the suit regains its original buoyancy and the diver rockets to the surface.

Yes, the loss of buoyancy of a neoprene drysuit can be compensated with the wing. Now at depth you are compensating for buoyancy and thermal protection. What's the point?

 

[Doppler]

Yes, Steve, I know.....I know. Just answering a question.

Figured that... but threw you under the bus to make a point... knew you could take it in the spirit it was intended! LOL! Anyway, what utter ****ing bull****.

---------- Post added November 13th, 2014 at 07:26 PM ----------

Yes, Steve, I know.....I know. Just answering a question.

---------- Post added November 13th, 2014 at 04:52 PM ----------



... A neoprene suit, at depth has lost its buoyancy and its insulating properties. The draw back with a thick wetsuit at depth is a neutral diver at the beginning of a dive that had a wing failure now has to attempt to swim up with lead that had to neutral a thick wetsuit (20-25#?) or dump weights, where upon ascending the suit regains its original buoyancy and the diver rockets to the surface.

Yes, the loss of buoyancy of a neoprene drysuit can be compensated with the wing. Now at depth you are compensating for buoyancy and thermal protection. What's the point?

I dive an O'Three 1-100 neoprene drysuit with a variety of thermals... Pinnacle Inferno is exceptionally comfortable for cool water... a rebreather and use NO lead at all. Any technical diver who needs 20 - 25 pounds of ballast, has issues that need to be resolved BEFORE they dive beyond 60 feet. By the way, I have noticed very very little buoyancy shift wearing this suit at depths in excess of 75 metres.

 

[bradells]

Hello: I am wondering why does UTD not allow neoprene drysuits? I am quoting from the UTD website ... "Dry suits should be constructed of a non-buoyancy changing type material. Neoprene suits (buoyancy changing) should not be considered for diving at any level simply due to bulkiness, variable buoyancy and thermal protection characteristics. The use of Neoprene as dry suit material causes the undesirable situation of ensuring that the diver is overweighed and has lost a certain percentage of thermal protection during the bottom portion of his dive. Being overweight on the bottom forces a diver to have too much air in the suit/BCD which can cause trim, drag and efficiency issues. Balanced suits on the other hand have minimal buoyancy-swing characteristics. The downside is that they as well offer little in the way of thermal protection. To over come this, some form of undergarment is necessary. (See section on undergarments.)" This seems to be a very poor case for ruling out the use of neoprene suits. I have owned both shell suits and neoprene suits and I wear less lead in my neoprene suit than in shell. Neoprene needs less undergarment for the same temperature and can be stitched closer to the body due to its flexibility thus reducing the air-pocket. Are these simply "recommendations" or are the UTD members / instructors obligated to comply by these "standards?" Thanks -

The nature of neoprene goes against one of their core values, which is that the wing only holds volume to displace the weight of gas in the tanks. Not for neoprene compression at depth.

Drysuits are inflated just enough to take away squeeze.

Whether that works out realistically in real life or not is a different story. UTD in some materials state they don't allow anything at or above 7mm wetsuits because of this as well.


BRad

 

[tbone1004]

for clarification, this only applies to non-crushed neoprene right? Crushed neoprene doesn't compress, hence crushed..... No buoyancy change at depth....

 

[Rich Keller]

Rich, well.....I think after a wing failure a prudent diver may want to end the dive. A neoprene suit, at depth has lost its buoyancy and its insulating properties. The draw back with a thick wetsuit at depth is a neutral diver at the beginning of a dive that had a wing failure now has to attempt to swim up with lead that had to neutral a thick wetsuit (20-25#?) or dump weights, where upon ascending the suit regains its original buoyancy and the diver rockets to the surface.

Yes, the loss of buoyancy of a neoprene drysuit can be compensated with the wing. Now at depth you are compensating for buoyancy and thermal protection. What's the point?

I dove for years in thick neoprene wetsuits before BCDs were invented without a problem. If your knew how to weight yourself properly this would be easy. In an emergency where both my BCD and neoprene dry suit fail I can still drop the weights and get to the surface. In the same emergency doing it your way even if you dropped the weights you are still going to be negative and have to swim up.

 

[Diver0001]

I'm not UTD so I can't address their policy directly; however, I will say that I agree with it.

Even using a trilaminate drysuit the diver must compensate at deeper depths for changes in buoyancy. Why would you want to make this any worse? I think you'll discover if you dive to significant depths that UTD's observations are compelling arguments in favour of trilam.

R..