Freezing My Ass Off...

[JohnN]

John,

Every well qualified drysuit diver I've ever had as a team mate endeavors to keep their drysuit volume as near constant as possible, just enough to remove the squeeze, and allow for the mobility required for a valve drill. This no doubt is what BoulderJohn was referring to.

That in practice the volume varies by a few percent, but the density varies pretty much lock step with ambient pressure does nothing to invalidate my point that it's density and not volume that varies in a properly operated drysuit.

I realize you are desperate to try to explain your misuse of the term volume with ever more strained arguments, but the fact remains the "ideal drysuit", which BTW is the exact term I referenced waaaaay back in this discussion, is a constant volume device.

Perhaps you should chat up a physics teacher and see what they have to say on the matter.........

Tobin

Tobin,

With all respect my physics are sound. You have now gone from "constant volume" to "as near constant as possible".

Entirely different things,unless you're channeling your inner Lewis Carroll (or Donald Trump)

“When I use a word,” Humpty Dumpty said, in rather a scornful tone, “it means just what I choose it to mean—neither more nor less.” “The question is,” said Alice, “whether you can make words mean so many different things.” “The question is,” said Humpty Dumpty, “which is to be master—that’s all.”

If the original statement had started out as "as near constant as possible", then we would be in violent agreement

 

[JohnN]

OMG, are you going to argue that because as I descend and ascend, adding or subtracting air from the suit as I do to maintain the proper volume, that it is not always perfectly exact and thus not "constant"? Is that what you are saying? If so, then Wow! You are correct sir! There will be times when it is not perfect, and that is why you feel the need to add or decrease air. It is thus not, in fact, constant.

This was a most illuminating discussion. One does not often meet people who make arguments like this in public discourse. It has broadened my horizons.

Happy to oblige. You're the one that started us down the rat hole with the mis-use of "constant"

How many times have you explained Boyle's law to beginning scuba divers?

noun

1. 1.
   a situation or state of affairs that does not change.
   "the condition of struggle remained a constant"
   synonyms: unchanging factor, given
   "dread of cancer has been a constant"

 

[tarponchik]

Just curious, why is everyone talking about 7 mm? What happened to 8 mm? Or do you guys mean "7 or 8 mm" or "7/8 mm" when you say "7 mm"?

 

[cool_hardware52]

Happy to oblige. You're the one that started us down the rat hole with the mis-use of "constant"

How many times have you explained Boyle's law to beginning scuba divers?

John,

I design, manufacture and sell BP&W's That a type of Buoyancy Compensator.

Selecting the proper wing capacity frequently depends on the Buoyancy of the Diver's exposure suit.

I deal with mostly newer divers. These divers easily understand the mechanics buoyancy associated with a wetsuit, but frequently have zero experience with drysuits, but may be contemplating one.

As such it is routine for me to explain how a dry suit works, and how a drysuit can lose buoyancy in the event of a total failure.

I routinely discuss the concept that the ideal drysuit is a *constant volume device* and when in good operating condition behaves differently than a wetsuit, i.e. a *constant volume drysuit* will not provide less buoyancy at depth than at the surface, but has the potential to lose all the buoyancy they start with.

I've done so 2-3 times on a typical day for the last 13 years. 250 work days a year x 2.5 divers x 13 years leaves me with an estimate north of 8000 divers.

Frankly I was shocked to learn today that I'm "Bat **** crazy" and unqualified to discuss such topics........

Tobin

 

[MaxBottomtime]

I made over 800 dives in SoCal in wetsuits and was usually cold. Sometimes miserably cold. The last time I wore a wetsuit here was for a deco dive on the Olympic II wreck. I shivered during our extended stops and even after showering on the boat, getting into dry clothes and a parka I was still shivering when we got back into the marina. I bought my first drysuit the next day and haven't looked back.

I've had used suits from Ebay with varying luck. I paid $300 for a USIA bilam suit with underwear and "repair kit" (a roll of black tape). I got a few hundred dives out of that suit before giving it to a buddy. I think it's still being used.

Buoyancy control with a drysuit is not an issue if you use your BC for its intended purpose. As long as you don't use the drysuit as a BC you really don't need to spend even more money on a class.

 

[TMHeimer]

Just curious, why is everyone talking about 7 mm? What happened to 8 mm? Or do you guys mean "7 or 8 mm" or "7/8 mm" when you say "7 mm"?

7 mm farmer john is the norm here. 8 mm is unusual. It's the 14 mm on your torso that makes the farmer john work (to a point)-- and 3 fingered mitts-- if it's say 45F water down to near freezing.

 

[Steve_C]

Have rented a number of 7 mm and have one of my own. I think that a 7mm with an integrated hood is warmer than a 7 mm with a separate hood. Some 7mm and some 5 mm now have internal seals that greatly reduce water flow along arms and legs. My 5 mm has them and I think they help. If you can get more on the core it can make a big difference. Dove a 10/14 a few times in Vancouver (Think a farmer John but the pieces are connected). Was toasty warm in 48 degree water. Point is that 7 mm vary greatly in how warm they are. Also I wear insulated dive socks inside my dive boots. I do this mainly for comfort and to reduce chance of any blisters but it also puts 8mm on the feet and that makes a big difference also.

 

[laikabear]

I doubt I could get a drysuit and get comfortable with it before my class, which starts June 4.

I can't afford to get a drysuit right now anyway. The cost of the Fundies class and all the gear and stuff required is going to be around $2000 when all is said and done.

So for the class I guess I have the option of just being cold, or maybe trying to layer 2 wetsuits, or getting the custom suit. When I posted I thought I was going to go the custom wetsuit route but now I'm not sure. I think I'm going to just try to layer the 2.5 and 7mm suits and tough it out.

 

[cool_hardware52]

I doubt I could get a drysuit and get comfortable with it before my class, which starts June 4.

I can't afford to get a drysuit right now anyway. The cost of the Fundies class and all the gear and stuff required is going to be around $2000 when all is said and done.

So for the class I guess I have the option of just being cold, or maybe trying to layer 2 wetsuits, or getting the custom suit. When I posted I thought I was going to go the custom wetsuit route but now I'm not sure. I think I'm going to just try to layer the 2.5 and 7mm suits and tough it out.

Fill a couple thermos bottles with hot tap water. Preheat the thermos, i.e. fill it up with hot water, let it sit a few minutes then dump it out and replace. Take these with you to pour into your suit between dives.

Take a big, black "contractors" grade trash bag and cut arm and a neck hole. Slip it on during Surface intervals to keep the wind from cooling by evaporation. On a sunny day the black blags can get down right hot. These also make a handy place to change, and you can throw it away when you are done.

Tobin

 

[elgoog]

...Slip it on during Surface intervals to keep the wind from cooling by evaporation...

I think this is key - it's how I survived my Fundies class. I didn't use the garbage bag method but absolutely believe having something on during the SI is critical. Personally, I have a Surfur parka but you can use any oversize fleece jacket. I would recommend the Surfur - even with a drysuit. I still use it to change and for when I've got my base layer and undergarments on and setting up my rig. By the time I'm done, I'm nice and warm and ready to put the drysuit on.