Trim with 2 and 4 tanks

[Jens Bölte]

Hello,

So, in case you need your reserve, you dekitting parts of your reserve and shot it to the surface to stay buoyant?

BTW, do you dive wet or dry?

Best wishes Jens

 

[TecRec50]

Hello,

So, in case you need your reserve, you dekitting parts of your reserve and shot it to the surface to stay buoyant?

BTW, do you dive wet or dry?

Best wishes Jens

Wet 3mm

 

[Jens Bölte]

Hi, with my 1Kg weight, I can have both my 2 main sidemount tanks (S80) almost empty at 20 bars only and still I can stay at the 3m decostop, just by exhaling a bit more and keeping my lungs slightly smaller ... Then, when I add 1 or 2 decos (S80 as well) I do not add any weight ... I just plan to lower the weight on the central system of my Xdeep to keep having a good trim. I do not like to be too heavy at the beginning of the dive ... What do you think of this ? Do you add more weight if you add more deco tanks S80 ? Kind regards and nice bubble

Well, on a deco stop you shouldn‘t keep your lungs „small“ but rather breath properly. The plan is not to be properly trimmed and buoyant at the beginning of the dive, but rather at the end. So, adding one or two kg to get trim and buoyancy correct at the end of the dive is what you should be looking for. If lowering the weight helps you to get a proper trim and to stay at your deco stop without problems (or adjustment such as small lungs), you are fine.

Measure the weight/buoyancy of each of your tanks when empty and when full, with all gear attached. Determine how much weight you need just for you, suited up. Use these numbers to determine the amount of weight you need. This way you know for certain. You can‘t beat physics.

Best wishes Jens

 

[Jens Bölte]

Wet 3mm

Ok,

With 3 mm your don‘t need a lot of lead to compensate the buoyancy of the suit. But you also don‘t have a lot to compensate the buoyancy of the gear. I prefer diving in a dry-suit when diving with four cylinders.

Do you have the xdeep tec RB or the ordinary xdeep tec? What do you do in case of bcd failure when you are diving the ordinary xdeep?

Best wishes Jens

 

[TecRec50]

Well, on a deco stop you shouldn‘t keep your lungs „small“ but rather breath properly. The plan is not to be properly trimmed and buoyant at the beginning of the dive, but rather at the end. So, adding one or two kg to get trim and buoyancy correct at the end of the dive is what you should be looking for. If lowering the weight helps you to get a proper trim and to stay at your deco stop without problems (or adjustment such as small lungs), you are fine.

Measure the weight/buoyancy of each of your tanks when empty and when full, with all gear attached. Determine how much weight you need just for you, suited up. Use these numbers to determine the amount of weight you need. This way you know for certain. You can‘t beat physics.

Best wishes Jens

S80 with valve + reg are neutral at 70 bars. I plan my dives to finish with both my deco tanks at 70 bars minimum, that's why I do not add any weight when switching from a 2 tank configuration to a 4 tanks configuration ... and you, do your change your weights if adding deco tanks ? Regards

 

[Jens Bölte]

Hello TecRec50,

Well I learn to plan for one error to occur, deco gas lost, minimum gas, exceeded time and depth, aso. In real life, I never had to share gas, lost my deco gas. But I exceeded time once. So for most dives I am well within my limits but I never for the intended limits, usually 100 - 120 bar, but for an error to occur. So, yes I change weight when switching when adding deco tanks.

Regards Jens

 

[SysGreg]

The plan is not to be properly trimmed and buoyant at the beginning of the dive, but rather at the end.

Agree. You can not assume you always came up with 70 bar, there be situations with higher gas consumption due to different issues including stress, currents, contingency, etc. If you have 2 tanks you are lighter by 5 kg at the end of the dive, with 4 tanks it doubles to 10kg. There is no way to compensate for the extra 5 kg of gas you loose unless you add those 5 kg at the beginning of the dive in terms if weights.

The crucial is to arrive to latest and longest deco stop being neutral, independently of amount of gas left in the tanks. If you are suddenly too light, you will be shoot up to surface even before you have a chance to disconnect your cylinder, holding DSMB in the other hand. Expansion of the wetsuit neoprane cells are highest between 6 m and surface which adds to already positive buoyancy at the end of the dive.

To excersice it take half empty tanks to shallow water and start with two tanks and then 4 tanks, bring some weights and a buddy who will add them for you as required. You may not like to be heavy at the beginning of the dive, but somehow you will need to accept that fact.