ScottyK:
Bob- a semi dry is just a wetsuit with better quality seals. It doesn't cost what a real drysuit does.
Don't buy a two piece! They are not warmer than a good quality one piece, and will require you to add a lot of lead. The guy who told you that is probably trying to unload excess inventory as no one is buying them anymore.
My lady switched from a farmer john to a nice $300 one piece wetsuit a couple of years ago. She is warmer now than she was before. She is petite, and hates the cold, but dives up here from May to November in her fullsuit.
I wouldn't agree with that...
If the farmer john/jane fits properly it will be warmer, you do have 13mm+ around your torso..
A poorly fitting farmer john/jane will be colder than a good fitting jumpsuit..
a poor fitting jumpsuit will be worse than both..
Women in general are the hardest to fit, men with above average proportions also offer a challenge.. these days every wetsuit manufacturer with the exception of one is using neoprene blends so the thermal protection various greatly at the same thickness... titanium is BS
The only manufacturer using 100% neoprene is wetwear, they make custom (25 plus body measurements) and stock suits.. Since they are using 100% neoprene the suits are expensive but they also are the warmest and most durable... I get suits free or at greatly discounted prices from several sources.. but I ended up paying (my suit is an $800 wet suit- the base price is around $500 plus extras)for a full custom 3mm suit for my deeper warm water diving because I was able to go full custom and get it made out of g-231 which doesn't compress very much (at 200fsw its virtually the same thickness as the surface).
Since its fully custom there is virtually no water movement and it doesn't compress, my 3mm wetwear is warmer than my 7mm (not going to mention the brand) at depth)
at 100 fsw depending on the blend most suits are not signifcantly thicker than 25% of their original thickness.
Wetwear is at most dive trade shows, with their mini chamber showing various material samples from competitors wet suits next to their own and pressurizing the chamber.. Its amazing how much it varies between manufacturers..
If you can get a farmerjohn that fits correctly you definately will be warm but you will need more lead... if you have a good tolerance for cold a properly fitting 7mm suit should be adequate for most divers june on through november, some people are confortable in colder water so then can push it a bit more... april/may in a sinlge 7mm really depends on ones tolerance for cold..
A big problem for many divers is water down the back.. Get a wet suit with a spine pad.. It makes a world of difference!