Sidemount, Drysuit and Weight Hell

[FiddlerOnTheRoof]

Thanks for you replies everyone.
I agree with you, 40 seems like a lot, and this is the reason why I started this post and the reason I thought about the ditchable weights. I'm not used to diving with so much weight and it's making me nervous.

My drysuite is not compressed neoprene and is a shell type of suite. The only difference is the material is a bit thicker then most shell type suits. I had it custom made for me with a thicker material so it could withstand the elements of wreck diving better. I have torn drysuits while wreck diving before!

I do follow all the procedures of removing air from the suit before entering the water and try to squeeze as much as I can before entering the water, also leaving the dump valve on setting 1 or open to allow water pressure on entrance to squeeze more out. Now once I am under I use air or Argon to inflate my drysuit. Last weekend the water was only 43 degrees!

I know I'm probably going to get chewed for this, but the way I learned to dive drysuit is to use it to establish neutral buoyancy and not use the wing/bc unless you really need it... isn't that how you do it?

 

[tbone1004]

ok, so on trilam that is way too much weight.

There are two schools of thought for drysuit bubble management. One is the way you learned, this stems from poor instruction and instructors/agencies not believing that students can actively maintain two bubbles. It is the "easy" way to do it, and for single tank 80's or 72's, it is fine because the amount of air is pretty negligible. You remember learning to dive when you just used your lungs to compensate for a single tank without a wetsuit, so it's easy.

With double steel tanks however, the amount of gas that you need to just lift the tanks is incredible. You have 16lbs of gas alone that you have to compensate for, on top of any inherent negative buoyancy that your rig has, which for you should be none, but for those of us diving the same configuration in 70* water in cave country, it is a very different story. What you do here is you put just enough air into the suit so you are comfortable, and buoyancy is compensated for by the wing. This keeps the bubble in the drysuit fairly small which improves drag, limits the propensity to get huge amounts of air in the feet which restricts movement and can cause an uncontrolled feet first ascent, etc etc. This is the way I recommend diving. You will likely have much more air in your suit than I would, however it is still trying to maintain a minimum suit volume to stay comfortable. Try that, see what lead you can start taking off, you may be surprised. For what you describe, I would be surprised if you needed more than 10-15lbs

 

[FiddlerOnTheRoof]

Thank you Tbone... I like your suggestions. I will try this weekend. Always learning in scuba!
On a different note... have you tried the 5 foot method in sidemount, keeping the hoses in clips infront or in the chest area versus routing them around the neck?

 

[tbone1004]

tried it, not a huge fan of that option in a cave as the regs tend to dangle. I currently do a double cross since I use Poseidons where the right tank reg hangs on my left side. Prevents the regs from dangling. I don't like 5' hoses in general, not long enough for real single file exits, so I have 7' and or 9' hoses depending on who I'm diving with *my primary cave buddy is 6'6" and I'm 6'4" so 7' is very uncomfortable for us to air share single file.

This video below shows how to make things much better if you choose to come straight up to the shoulders. IMHO it is superior for all second stage bolt snaps whether in backmount or sidemount since it prevents everything from dangling and is easy to remove.

 

[FiddlerOnTheRoof]

Can't watch the video, you posted it as an image...

 

[tbone1004]

it shows as a video for me, I embedded it as a video...

 

[Jim Lapenta]

I was also initially taught to use the suit for buoyancy and the wing or BC only if necessary. My instructor though also informed of the real world way of diving dry. Drysuits are not BC's. They are exposure protection. You only need enough air in the suit to offset the squeeze and maintain loft in the undergarments. Any other buoyancy needs are met by the BC. When I was commissioned to write the new SDI drysuit manual last year one of the things that they wanted to see was a chapter specifically stating this. What it said was up to me but I essentially made the same statement.

There is a point as many divers will tell you, under certain conditions, that the amount of air needed to offset squeeze in the suit will also be the amount it takes to get neutral; if you are properly weighted, but you need to do the suit buoyancy test.

However with new, better fitting, suits and undergarment technology this is not necessarily the case. You can be warm and still be very negative when diving steel tanks and carrying stages, reels, lights, etc. Adding air to the suit to offset this is poor practice and perhaps dangerous.

You now have a larger bubble to manage with the suit which may less effective at venting than your BC. So once you have offset the squeeze you now use the BC to manage for neutral buoyancy. Easier to fine tune, easier to vent, and a smaller bubble to manage as it can only move within the confines of the bladder rather than the entire suit.

 

[FiddlerOnTheRoof]

it shows as a video for me, I embedded it as a video...

I got it... It doesn't work on IPad but it works on regular PC...!

 

[FiddlerOnTheRoof]

tried it, not a huge fan of that option in a cave as the regs tend to dangle. I currently do a double cross since I use Poseidons where the right tank reg hangs on my left side. Prevents the regs from dangling. I don't like 5' hoses in general, not long enough for real single file exits, so I have 7' and or 9' hoses depending on who I'm diving with *my primary cave buddy is 6'6" and I'm 6'4" so 7' is very uncomfortable for us to air share single file.

This video below shows how to make things much better if you choose to come straight up to the shoulders. IMHO it is superior for all second stage bolt snaps whether in backmount or sidemount since it prevents everything from dangling and is easy to remove.

So Tbone from your reply and if I understand correctly you are not routing your hoses hog style around your neck?

 

[FiddlerOnTheRoof]

I was also initially taught to use the suit for buoyancy and the wing or BC only if necessary. My instructor though also informed of the real world way of diving dry. Drysuits are not BC's. They are exposure protection. You only need enough air in the suit to offset the squeeze and maintain loft in the undergarments. Any other buoyancy needs are met by the BC. When I was commissioned to write the new SDI drysuit manual last year one of the things that they wanted to see was a chapter specifically stating this. What it said was up to me but I essentially made the same statement.

There is a point as many divers will tell you, under certain conditions, that the amount of air needed to offset squeeze in the suit will also be the amount it takes to get neutral; if you are properly weighted, but you need to do the suit buoyancy test.

However with new, better fitting, suits and undergarment technology this is not necessarily the case. You can be warm and still be very negative when diving steel tanks and carrying stages, reels, lights, etc. Adding air to the suit to offset this is poor practice and perhaps dangerous.

You now have a larger bubble to manage with the suit which may less effective at venting than your BC. So once you have offset the squeeze you now use the BC to manage for neutral buoyancy. Easier to fine tune, easier to vent, and a smaller bubble to manage as it can only move within the confines of the bladder rather than the entire suit.

Great information Jim... Thanks for your reply. Indeed like in many jobs scuba diving is an ongoing learning and upgrading adventure!