Drysuits

[Pierre Farrugia]

What is the difference betweena membrane drysuit to a compressed neoprene one. What are the cons and pros of both.
Which is the most flexible?

[rasilon]

Probably the best summary of the debate I've found is here:
http://www.ukrecscuba.org.uk/ukdiver/drysuit.html

[Dominic]

The UKRS is about non-compressed neoprene tho.

The basic take is that compressed neoprene has none of the bouyancy issues of normal neoprene suits, is stretchier and tougher than membrane suits, and a bit warmer as well. So it's considered the best thing to make a suit out of. Hence the price tag.

[Hobby]

It's a good article and raises all the important points.As you may gather it is a fairly personal thing,however.
I cannot speak with reference to tech diving,only on my own experience and of those around me.There will be others I'm sure able to give a perspective from that side.My observations come from commercial use and scuba(aside from "tech" which we'll take as comparitively deep with long deco stops for the purpose of this).These are of course my personal views and maybe useless but it may give you some ideas.
Membrane"types",by this I mean membrane,trilaminates etc.There are various material types available,I'll give some commercial links which go further into this after.Advantages I've found are comfort and ease of entry etc.when compared to my standard 8mm neoprene suits.The membrane type suits also dry off very quickly if that's of any bearing(it can be in commercial eg.driving between sites you don't have to de-kit).This also can make "field repairs" quicker and simpler to do than for neoprene.
Of course there is the lack of compression leading to bouyancy changes at depth,however,this has never been of consequence to me so I cannot really comment.What I can comment on is the terrible suit squeeze,even in a pool,in a membrane suit.Yes,add more air to compensate,but then you become more positively bouyant and so the cycle begins,personally I can live without that.The other issue is thermal protection.Neoprene has better inherent thermal properties than membrane types period.This maybe of lessconcern depending on the type of diving done and location.Of course you will wear undergarments but you can still be cold.
eg.A few years ago a Comm Diver died doing an inspection of a culvert grating in Anglesey(at 4 mile bridge),no deeper than 10 feet of water late summer.He became trapped,the tide turned and he experienced the seawater rushing past him.He had unlimited air,an 8mm neoprene suit,undergarments unknown but tragically died within 4 hrs from hypothermia.Illustrative of the effects of cold though.How long in a membrane remains to be seen,so consider the water temp carefully,it may not be as warm as you think!
If you experience a zip failiure or major leak(wrecking etc) you will become very cold quickly over here,moreso in a membrane type,in fact major leaks in membrane suits are'nt good news at all given the looser fit.In a membrane it can be unpleasant but not usually critical.Neoprene suits look scruffy quickly compard to membrane types,in my experience I've found neoprene very resiliant to hard work inc.burning,cutting etc.and most comm divers would tell you the same(or I'll look a fool!)Membrane types are widely used by comm divers..in cetain applications such as contaminated water where the material is easy to de-contaminate and tested to resist chemicals(Viking Trelleborg,Gates etc).These suits however are'nt the typical membranes as used in rec.diving.I've had a good quality new rec.membrane fall apart after a job in a pool,6 hrs exposure to the chemicals in the water effectively dissolved the glue!
Seals are often cited as being a major headache which is'nt really a problem.If you can't get neoprene seals to seal watertight(they're much warmer/stronger than latex)then fit latex seals to the neo.suit.It is'nt a problem,you can fit slightly larger neoprene covers over the latex seals to overcome their shortfalls.
I've worn the newer generation of compressed neoprene suits and found them to be as comfy as membrane types,so for me that argue dies on its backside,one of O3's newer suits for example has the outer surface impregnated with something to make it extremely restistive to puncture,tearing etc.
I'm not even going to mention "fashion aspects"or what certain bodies may say is best.It's like comm divers :- use right suit for the job.
Have a look through these articles,they'll give you a rough idea of some of the materials now used in suits for comm.applications but by names supplying to the rec.world too.Hope it's of some use!Hobby.
http://www.diveweb.com/commdive/features/021.01.htm
http://www.diveweb.com/commdive/features/026.08.htm
http://www.diveweb.com/commdive/feat...ust2000.02.htm