Do I have enough buoyancy with this 25lb donut

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johndiver999

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The fitting hitting the tank is not an issue, as far as I can tell.

Between the weight of the air in the big tank and the loss of buoyancy of the 7 mm suit, there is just not enough lift capacity to make me feel comfortable. What if you need to help a buddy and want to have 8 or 10 lbs of excess lift at depth? It is not an issue of weight distribution, it is an issue of having too little lift capacity.

First get a wing that can hold enough air, then fine tune trim and weight distribution..

You are swimming around with a big tank and a thick suit,.. using a slightly larger bc wing is not going to slow you down.

Also, if you have some lead to drop, the "issue" is not at the surface (when your suit is nice and fluffy) it is at 115 ft.
 

James79

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Thanks for the calculations! After talking to ppl on here I guess my fear is if I get down to 60-80 feet I wont have enough buoyancy to come up.
In theory your 7mm wetsuit will have about 14-20 lb of buoyancy at the surface. If you are weighted correct, you will start the dive with about 8 lb negative (to offset the air in your 120, so you don't end up corking at the end of the dive). If we worst case the estimates, and pretend that the wetsuit is completely compressible (which they aren't), then it looks like this: At 99ft you are at 4 atmospheres. Wet suit at 1 atm (surface) is 20 lb positive, compresses at depth to 5 lb positive (not really, though, probably closer to 10) for a loss of 15 lb buoyancy. So even at the start of the dive (full tank) at 99 ft, worst case you are 23 lb negative.... still within the lift capacity of your wing.

Respectfully,

James
 

lowwall

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What if you need to help a buddy and want to have 8 or 10 lbs of excess lift at depth? It is not an issue of weight distribution, it is an issue of having too little lift capacity.
If it's near the end of the dive, you have the excess lift between the few pounds of reserve lift and the 5-6 pounds of air that's no longer in the tank.

At the beginning of the dive, you might have to drop a weight or send up a dsmb. Or you could just kick up to where the suit expands. It's the start of the dive, so you won't have deco issues. Anyway you have lots of gas, so there's time to sort it out.

The point is that's the wing he's got and it will work. Better yet, with the change to a relatively streamlined BP/W setup, he'll soon be able to switch to an HP100 and everything will be perfect :)
 
OP
Seville

Seville

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If it's near the end of the dive, you have the excess lift between the few pounds of reserve lift and the 5-6 pounds of air that's no longer in the tank.

At the beginning of the dive, you might have to drop a weight or send up a dsmb. Or you could just kick up to where the suit expands. It's the start of the dive, so you won't have deco issues. Anyway you have lots of gas, so there's time to sort it out.

The point is that's the wing he's got and it will work. Better yet, with the change to a relatively streamlined BP/W setup, he'll soon be able to switch to an HP100 and everything will be perfect :)
Thanks, I am glad I can use it and I can at least use it for now. Seaquest one I was using had 40lb of lift so it is deff an adjustment change. Although with the sea quest it seemed tough to get all the air out sometimes. I am hoping to go to a steel 100 sometime once my air consumption gets better. I only get about 45 mins on the 120 and I got it so I could keep up with my buddies and did not feel bad about ending the diver early.
 
S

Speedway21

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Personally I would remove all the padding as you don't need it and you have to add lead to offset its buoyancy. I don't think the fitting will be an issue as you have the wing fully inflated in the picture but will not be when you are diving. I use a 30lbs wing with an 8mm suit with no issue and on the surface I never have it fully inflated as the suit does most of the work for me.
 
https://www.shearwater.com/products/swift/

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