MichaelMc
Working toward Cenotes
Todd, I also have a very thick suit, currently 15/10/5 farmer john and beaver tail but 20/10 in the past. Initially buoyancy control near the surface was a challenge. Careful use of lungs is the control. But with that much rubber, near the surface if you move 10' closer to the surface you need to carefully adjust the BC as well, to shift the range the lungs are working within. Your BC is there to compensate for suit thickness changes with depth over a wide range, and you have a lot of it. Any over weighting is going to make control harder by adding a BC bubble for all that extra lead.
A careful SS weight check where you pass off 1, 2, 3, ... pounds to a buddy or the sand below you and account for the air in your tank is key to getting your weight dialed correctly. Find the max you can pass off breathing calmly and still hold your depth. But have the extra ready at hand to pick up once you go past that point. Maybe try passing off 1, 2, or 3 pounds past the weight of your extra air each dive. If you can do that, start the next dive 1 or 2 pounds lighter. Keep that up until you find you can not pass off any weight past the weight of your air above 500 psi. At that point you have near the bare minimum for that SS depth. Because of your suit thickness, you will need to breath with more and more empty lungs as you make the final part of the ascent, or you can also add 1-2 pounds extra as a cushion and to help keep that final ascent slow. I finish my dives shallow, so I dial this in for 10' or less, which is reasonable as well.
I feel like a 6 lb. swing in the lead that lets you descend is more than extra air in the suit would account for. You might try the cold water advise of pouring hot/warm water into your suit before the dive for the warmth, and in this case air removal. That might give you more consistent buoyancy results while you work things out. Shallow exchanges with full lungs, from stress, will keep you up, and cause CO2 retention which leads to more stress. You may need to breath with near empty lungs to descend, and near empty lungs flush CO2 more efficiently.
(Very thick suits are often cautioned against in most cases due to control issues and large buoyancy loss at depth)
A careful SS weight check where you pass off 1, 2, 3, ... pounds to a buddy or the sand below you and account for the air in your tank is key to getting your weight dialed correctly. Find the max you can pass off breathing calmly and still hold your depth. But have the extra ready at hand to pick up once you go past that point. Maybe try passing off 1, 2, or 3 pounds past the weight of your extra air each dive. If you can do that, start the next dive 1 or 2 pounds lighter. Keep that up until you find you can not pass off any weight past the weight of your air above 500 psi. At that point you have near the bare minimum for that SS depth. Because of your suit thickness, you will need to breath with more and more empty lungs as you make the final part of the ascent, or you can also add 1-2 pounds extra as a cushion and to help keep that final ascent slow. I finish my dives shallow, so I dial this in for 10' or less, which is reasonable as well.
I feel like a 6 lb. swing in the lead that lets you descend is more than extra air in the suit would account for. You might try the cold water advise of pouring hot/warm water into your suit before the dive for the warmth, and in this case air removal. That might give you more consistent buoyancy results while you work things out. Shallow exchanges with full lungs, from stress, will keep you up, and cause CO2 retention which leads to more stress. You may need to breath with near empty lungs to descend, and near empty lungs flush CO2 more efficiently.
(Very thick suits are often cautioned against in most cases due to control issues and large buoyancy loss at depth)
