Drysuit use and buoyancy
- Thread starter Crazy_Canuck
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I dive D12 and 2.9kg backplate. Plus 1kg trimweigth.
Or single 12 with 6kg plus the 2.9 backplate.
Undergarment is 400g, but I really need to buy a thinner one for the summertime..
But regardless if I am overweighted or not. Why should the air that is put into the suit to release the squeeze, be more buoyant then the air at the start of the dive.
It's the same amount of air. Should make any difference
60plus
Contributor
In theory you should use your BCD for buoyancy control but in practice a correctly adjusted drysuit means you do not have to touch your bcd. At the surface fully deflate your bcd, you should not yet sink. Then fully open your drysuit shoulder valve and exhale, you should then sink slowly assuming you are correctly weighted. When submerged about 2 to 3 meters partially close your shoulder valve (usually about 3/8 or 1/2 torn on APEKS). At this point you should be neutrally buoyant and as a result have found your neutrally buoyant displacement. If not add a little air to the suit. You should be feeling a hint of suit squeeze but not uncomfortable. You should rise and fall as you breathe. As you descend add more air to your suit to keep the squeeze and displacement constant. At your chosen depth and with your left shoulder well above your feet open your shoulder valve until a few bubbles emerge then turn it back a click or two. Your buoyancy / displacement should now be correct, suit pinch minimal and your shoulder valve set so it will vent as you ascend, preventing excess ascend rate. You only need to re inflate your bcd at the surface. If you try to control buoyancy using both bcd and suit inflation whilst at same time as trying to control squeeze it is more complex and a mistake more likely to be made, particularly if you are trying to vent both suit and bcd at same time to control ascent.
If I remember correctly from a PADI dry suit course manual that may now be out of date, PADI did recommend using the dry suit for buoyancy but only for neoprene dry suits and for tech diving. Not defending that, just saying what I remember.
Use whatever you’re most comfortable with.
I use both. The BCD is the primary source of buoyancy in conjunction with the drysuit which is more convenient to dump some gas.
The drysuit can be a pain if you’re not horizontal as it dumps lots of gas if trimmed upwards (gas from your legs migrates upwards), so the BCD is better. Whilst at deco, warmth is way more important and you’re horizontal, so more gas in the drysuit than the wing.
I use both. The BCD is the primary source of buoyancy in conjunction with the drysuit which is more convenient to dump some gas.
The drysuit can be a pain if you’re not horizontal as it dumps lots of gas if trimmed upwards (gas from your legs migrates upwards), so the BCD is better. Whilst at deco, warmth is way more important and you’re horizontal, so more gas in the drysuit than the wing.
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