Optimal cylinder for an XDeep Zeos ?

[Roger Hobden]

What would be the optimal cylinder size for an XDeep Zeos that has a 17 Kg / 38 lbs lift capacity ?

This is the one cylinder model with minimalist webbing.

I will be doing mostly cold water diving, using a drysuit, either in lakes, or in the ocean.

I am looking to purchase a steel cylinder to minimize positive buoyancy changes at the end of the dive.

Edited for clarity.

 

[elgoog]

For coldwater, drysuit and reasonably thick undies, I like Worthington steel tanks because they're negative even when empty and reduce how much lead you need to carry. HP100 goes from -10lb full to -2.5lb empty compared to Faber LP85 which goes from approx -5lb to +1lb. For reference, my single tank HP100 rig with DUI TLS350, XM450 undies, BZ200 vest needs 18lb weight (8lb bolt-on BP plates and 10lb weight belt) with a steel plate.
Unfortunately, these tanks are not made any more and your only option is finding them used.

I am looking to purchase a steel cylinder to minimize buoyancy changes during the dive.

Not sure I'm following here. The buoyancy swing for a given amount of gas is going to be the same regardless of what tank you use. The buoyancy at the end, which you will use to calculate weighting, will be different but the delta from full to empty is the same.

 

[Roger Hobden]

Not sure I'm following here. The buoyancy swing for a given amount of gas is going to be the same regardless of what tank you use. The buoyancy at the end, which you will use to calculate weighting, will be different but the delta from full to empty is the same.

Sorry I used improper terminology. I meant that I wanted to use steel to minimize the effects of being positively buoyant at the end of the dive which is more apparent with aluminum tanks.

 

[Roger Hobden]

Not sure I'm following here. The buoyancy swing for a given amount of gas is going to be the same regardless of what tank you use. The buoyancy at the end, which you will use to calculate weighting, will be different but the delta from full to empty is the same.

Edited the OP to clarify my meaning.

 

[elgoog]

I meant that I wanted to use steel to avoid the effects of being positively buoyant at the end of the dive which apparently occurs with aluminum tanks.

Yep, that's what I figured but wanted to clarify. With doubles you may want a little more flexibility but for single tanks and drysuit, my approach is to find the most negative tank because I still need a fair bit of weight with those.

How tall are you? That's another thing to keep in mind for when looking at tanks to buy. HP80s are really short, HP100s are shortish but work fine for most people, LP85s are longer, HP120s are really long. This is going to be a factor in determining trim as well as ease of gearing up. Again, not as critical as in doubles but still can have an impact.

 

[Roger Hobden]

My height is about 5'10". Weight about 220 lbs.

 

[runsongas]

hp100 or hp119 if you need the extra gas and dont mind 8 inch tanks

lp85 if you can get cave fills

i am not a fan of the lp95 but some still like them

 

[Roger Hobden]

lp85 if you can get cave fills

Cave fills ?

BTW, is it accurate to say that LP cylinders have a slightly positive buoyancy at the end of the dive, compared to HP cylinders ?

 

[runsongas]

usually yes if they are fabers