Maintaining proper drysuit squeeze

[ijdod]

I seem to have a problem maintaining the proper squeeze in my drysuit. When descending, I use my wing for buoyancy, and only put enough air in my drysuit keep squeeze under control. The problem starts when returning to the surface. I am unable to vent as much air from the suit as I would like; I end up with an empty wing and trimming on my suit, and thus with a lot less squeeze that I would like. The (SI tech) dump valve is all the way open.

Weighting seems on the ball, with 40 bars remaining I can just stay submerged in the shallows (I mostly do shore dives), returning from a dive. However, if I surface and raise the dumpvalve above the water, enough air is vented out to make me overweighted at that point; I'm basically back at the amount of air in the suit I had at the start of the dive.

Does anyone know what I might be doing wrong here? Or is my dumpvalv simply acting up?

 

[jar546]

This is what works for me:

The only time there is air in my bc is when I am at the surface.

My drysuit is used for my buoyancy from the beginning to the end of the dive.

Upon ascent, since I don't have to let any air out of my BC, I have plenty of time to start releasing air from my drysuit. The valve on the drysuit does not seem to release air as fast as a BC (I use a back inflate) so you have to start letting air out sooner than you would with a BC.

I simply roll to my right which elevates my drysuit valve and it releases air.

Your mileage may vary but this works excellent for me. I think since you are putting air into 2 different pieces of equipment, you have more to manage.

 

[BB1]

The problem I ran into when trying to use just the suit is that when I first descend with full manifolded steel 12L's (twin 100's) and an AL40 deco and canister light etc etc I am really heavy.

Then the amount of air needed in the suit is quite large.

I ran into a lot of trouble trying to manage where that bubble was going - generally my feet

Something to keep in mind - YMMV

 

[spectrum]

ijdod

It sounds like you aren't able to exhaust suit air effectively.

*Dive with the exhaust valve wide open, especially on the return leg of the dive.
*Be sure you really have the valve as the high point when you want to vent. Have a biddy observe..
*Are you wearing garments that permit air migration to the escape point? Some have grommets and such to assist.
*Is the valve in good shape? it may not be regulating well. It could have dried salt/sand externally or internal lint contamination.
*Have you tried forcing the vent my pushing the valve manually?
*Do you have any gear strapped especially tight so it forms an air trap?

Pete

 

[spectrum]

ijdod

It sounds like you aren't able to exhaust suit air effectively.

*Dive with the exhaust valve wide open, especially on the return leg of the dive.
*Be sure you really have the valve as the high point when you want to vent. Have a biddy observe..
*Are you wearing garments that permit air migration to the escape point? Some have grommets and such to assist.
*Is the valve in good shape? It may not be regulating well. It could have dried salt/sand externally or internal lint contamination.
*Have you tried forcing the vent my pushing the valve manually?
*Do you have any gear strapped especially tight so it forms an air trap?

Pete

 

[ijdod]

This is what works for me:
Your mileage may vary but this works excellent for me. I think since you are putting air into 2 different pieces of equipment, you have more to manage.

I've found that using by wing for buoyancy gives me a lot more stability underwater, which is not something I'd like to lose. I also dislike the air bubble moving around. Thanks for the suggestion though.

ijdod
It sounds like you aren't able to exhaust suit air effectively.

I agree that pretty much sums it up.

*Dive with the exhaust valve wide open, especially on the return leg of the dive.
*Be sure you really have the valve as the high point when you want to vent. Have a biddy observe..
*Are you wearing garments that permit air migration to the escape point? Some have grommets and such to assist.
*Is the valve in good shape? it may not be regulating well. It could have dried salt/sand externally or internal lint contamination.
*Have you tried forcing the vent my pushing the valve manually?
*Do you have any gear strapped especially tight so it forms an air trap?

- Valve is always wide open.
- Check. Even go as was as floating sideways to absolutely positively get the dump at the highest spot. Will have my buddy doublecheck the next dive though.
- My undersuit has the grommets, and I also tried some of the other tricks that should prevent the valve from being blocked on the inside.
- The valve is one of the parts I suspect. It should be fine (it's clean and seems to work), but it might not be.
- Forcing it open doesn't seem to do much, but then again it never did, even when I used my suit for buoyancy. Probably due to the valve being wide open anyway.
- Just the bp webbing, which isn't that tight.

Assuming correct position (will doublecheck next time I hit the water), it almost seems that the valve will vent all it's going to vent, but that is less that I'd like it to. Could it be that I might be too light?

 

[spectrum]

ICould it be that I might be too light?

If you are still able to remain down in the shallows with a light cylinder your weight is adequate. While diving on the return leg of a shore dive you won't get the same vacuum packing that occurs when you are vertical at the surface, you just don't have the pressure gadient to drive that much air out. You may need to adjust your expectation of the drysuit's fit.