Buoyancy, is it the suit or me?

I have two suits, a 3mm one piece and a 7mm two piece farmer john.

I am about 5' 11' and 185 lbs. In fresh water in the 3mm I dive with 6 lbs and have no problems with buoyancy, let out air at surface and can descend on exhale, and hardly ever add air at bottom till below 40 feet and can hover at 15 feet with 500 psi no problem.

Now with the 7mm I cannot descend no matter how much weight I wear. I have to do a jacknife kick and swim under to below 15 feet. once at twenty I level out and deeper of course have to start pumping air.

With 16 lbs I am most comfortable at depth, but cannot stay at 15 feet at all. I have had up to 30 lbs on trying to descend by exhaling, and still have to swim under.

I can do the PADI buoyancy check at surface with 22 lbs and float at eye level. But stay there no matter how much I exhale.

This suit has about 10 dives on it, as I will brave the cold in my 3mm rather than fight it. But i do want to dive in this suit.

After going deep and forcing out the air it doesnt seem to help.

Any advice? It is a Henderson Neosport.

I suggest you focus on your bouyancy at the end of a dive at the rest stop. If you get that right, you will be able to work thru other situations. Sounds like the 7mm is not only very bouyant as you would expect, but also trapping air which makes it a bit more difficult. Once you get your weight right, you may have to spend some time at the beginning of each dive wiggling those bubbles out. Or just continue with your current technique of swimming down if you are in a hurry. I add 1 extra lb to what it take at rest stop with 500 psi, so I can take the tank down to almost empty without losing control of bouyancy.

It might be good if you weigh each piece of neoprene to determine weight requirements for each. A pool or other calm water, a mesh bag tied to the neoprene and an assortment of lead will do the trick. Your 3mm is probably around 6lb + bouyancy. Each piece of your 7mm should be around 8lb + bouyancy. If that were the case, you would need to add 10 lb when going from the 3 to the 7mm.

remember you are going to use about 3-5 lbs of air through your dive (even if your tank is negative throughout the dive)

If you can bearly get down at the start of the dive you are going to be unsafe at the end. Ideally you should get down with ease because you are a bit heavy then be negative at the end where it really matters with all the N2 in your system.....

That is what the previous post was getting at.

Pete

awap once bubbled...
Sounds like the 7mm is not only very bouyant as you would expect, but also trapping air which makes it a bit more difficult.

It might be good if you weigh each piece of neoprene to determine weight requirements for each.

Click to expand...

Thats a good Idea and I am going to try it. I think you are right about air trapping. Would unzipping suit and flooding it with water at beginning help.

Yesterday I dove in this suit and was able to lay around at 12 to 15 feet with 20 lbs of lead and 750 psi left in tank. I have been told that the suit will loose buoyancy as it gets loosened up.

Should I try a few deep dives to loosen it up?

thanks again

mike

WVMike once bubbled...
I have been told that the suit will loose buoyancy as it gets loosened up.

Should I try a few deep dives to loosen it up?

Click to expand...

Neoprene permanently crushes a bit over time due the the compression at depth and this will cause a new suit to lose a few to several of pounds of bouyancy after several dives. the degree to which this occure depends on the quality and charactoristics of the neoprene used in the suit.