The Journey to Decompression Procedures with Sidemount

[kensuf]

Excellent ideal.

However how heavy is that? Back issues is why i chose SM over BM doubles.

Do you support the tanks while taking the giant stride?

Chokers clip the bottles onto d-rings and hold them into place.

 

[DiveLikeAMuppet]

Yes I understand and I have been working Fundamentals. My question was roughly how much tolerance is acceptable for the tanks. So if my tanks float up by let's say 2 inches and it takes me 5 min to correct it, on my own would I be penalized?

What will get you penalised is acting unsafe, not hitting stops, not switching gas safely, not being able to solve problems and not maintain depth / team awareness. I doubt that most instructors would care about tanks being a bit out of trim.

 

[lostsheep]

Yes I understand and I have been working Fundamentals. My question was roughly how much tolerance is acceptable for the tanks. So if my tanks float up by let's say 2 inches and it takes me 5 min to correct it, on my own would I be penalized?

No one can answer how your instructor is going to judge you except your instructor for a subjective assessment like this.

 

[grantmac]

I'd want an instructor who would at least mention and coach tank trim.

That said I've seen lots of SM AN/DP footage both local and abroad with truly awful tank trim.

Team awareness, body positioning and buoyancy are all more important skills.

 

[Tigerpaw]

Thanks for the input everyone. Just trying to work hard at it and make the best use of my training time.

 

[TheCatFish]

Good on you you’re pre-practicing and pacing yourself

I had my awakening moment in similar circumstances, jumping into some minimal surge, not as chilled as slow shore entry

Do you already use a 3rd tank? My 1st couple of dives for combined AN+DP I used dummy deco tank (21 instead of 50%) to practice exactly that

In my case I dove sidemount only witg floaty AL80s, had to keep all the bungees/tieoff boltsnaps on tank bands very tight anyways (just like diving only 2 tanks)
For the main bottles I used just rope so as tight as possible without tolerances, and used a short bungee for the 3rd tank gave me the tolerance needed to help having leverage to “thread through” to the drop D; in class you’ll need to manipulate a lot not just don/doff begin/end of dive and drop the tank while managing your trim.
Your DP instructor will comment on their trim and positioning so you’ll probably also fine tune between dives
Edit: oh the one important thing about 3rd tank placement, the gas label sticker, for NoTox drills (in my opinion the most important skill to learn in DP): you need to be able to see it and “minimal” tilt-to-show to your teammate/instructor for confirmation, so tank rotation is a consideration

To answer your question, there’s emphasis on streamlining but for sure there is some tolerances

Can’t speak for steel tanks one bit

All great points. Comment about steel tanks:

They're heavy. (Duh). If using large volume steels then you will defintely be incorporating their weight into your baseline buoyancy. I have a steel 40 that I've got cleaned and set aside for my O2. It's pretty cumbersome to deal with when full and you have 1 AL80 on each side and you attempt to stack the AL80 with the st40. Sometimes I will cross clip the st40 to my crotch ring and chest D ring, since it is one of the first things I drop off at 20ft. YMMV depending on conditions and tank management needs. Once the bottle starts to empty then the weight becomes similar to an AL80 and eventually will get positively buoyant as well, at which point, clipping it off to the right side in propper trim is trivial.

In a more perfect world I would probably use an AL40 for O2, but this tank was made available to me for the price of a lunch, so I went with what the universe provided.

And, in reference to doing neutrally buoyant NoTox drills in this config? It's totally doable, but the task lands somewhere between miserable and hilarious.

 

[TheCatFish]

Yes I understand and I have been working Fundamentals. My question was roughly how much tolerance is acceptable for the tanks. So if my tanks float up by let's say 2 inches and it takes me 5 min to correct it, on my own would I be penalized?

Depends I guess. In a cave it can be important, in open water it really doesn't matter in the slightest other than for looking picture-perfect and perfecting good practice. Also, tank float happens gradually, you'll feel the tank moving up along your thigh. There's usually a very familiar sensation of bonking the tanks with each frog kick. When that starts to go away, you know the tanks are migrating up above your legs. This is why I prefer sliding DRings with that set up, because the tanks can be adjusted as necessary. Otherwise if you use fixed D rings then you wait for a certain amount of buoyancy before moving them. YMMV, plenty of people swear by fixed D rings.

 

[rjack321]

Depends I guess. In a cave it can be important, in open water it really doesn't matter in the slightest other than for looking picture-perfect and perfecting good practice.

Tanks hanging and going every which way is both sloppy and radically increases drag. Drag creates work and effort. More work and effort leads to more gas consumption and more CO2 to blow off. It's all connected.

 

[Tigerpaw]

And, in reference to doing neutrally buoyant NoTox drills in this config? It's totally doable, but the task lands somewhere between miserable and hilarious.

I'm about to find out next week. So fay I worked trim/buoyancy, finning and valve drills. Next week I start don and doff stage tanks. That will be interesting to say the least. I tried it before and was everywhere! Will come back and post here how it went.

 

[Tigerpaw]

Tanks hanging and going every which way is both sloppy and radically increases drag. Drag creates work and effort. More work and effort leads to more gas consumption and more CO2 to blow off. It's all connected.

Yes, very true, my main question was how much was allowable for testing purposes. On one of my dives I noticed my tanks were drifting and I eventually corrected it. I was wondering if there was a time limit or certain amount of floating before I would get dinged on it. The consensus is it's up to the instructor BUT if I am adjusting my tanks I shouldn't get dinged for it.