Where does that come from?
The information came from an equipment seminar that I attended several years ago.
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Where does that come from?
Can you explain why it should be 10 lbs greater? It seems like if weighted for neutral bouyancy with used cylinder at the surface, then lift would only need to be inversly proportional to the weight you wear to be neutral at depth. 2-4 lbs extra lift would give more than enough room for error. Or is there something i'm not thinking of?
Can you explain why it should be 10 lbs greater? It seems like if weighted for neutral bouyancy with used cylinder at the surface, then lift would only need to be inversly proportional to the weight you wear to be neutral at depth. 2-4 lbs extra lift would give more than enough room for error. Or is there something i'm not thinking of?
ok, so if it takes 14 lbs of lead to "sink" the 7mm wetsuit, then it would take 14lbs of lift to raise the weights once the wetsuit is collapsed. that is where i get the concept "inversely proportional". In the same scenario, at the surface the wetsuit offsets the weights, so now very little extra lift is required for the head.depending on suit thickness, you want some extra room to keep your head clear of the water. It's not the amount of lead though, it's the amount of buoyancy change. I.e. diver 1 a manatee and are in a bathing suit and need 14lbs of lead. diver 2 is jacked and is in a 7mm suit and needs 14lbs of lead, both divers carry all lead on a weight belt, tank is an al80. Diver 1 does not need that 14lbs factored into their wing because that buoyancy is fixed. Diver 2 needs to factor it in because the wing will need to lift that lead at the bottom.
In OW scenarios, I typically do suit buoyancy plus gas in tank, plus 10lbs to give me enough lift to keep my head all the way out at the surface if I need to. In a cave it's not really necessary though having a buffer is good if you need to pick anything up
that makes sense. thanksIf you ever have to rescue another diver, it's very helpful to have some extra lift.
Can you explain why it should be 10 lbs greater Don't forget the tank? It seems like if weighted for neutral bouyancy with used cylinder at the surface, then lift would only need to be inversly proportional to the weight you wear to be neutral at depth. 2-4 lbs extra lift would give more than enough room for error. Or is there something i'm not thinking of?
gotcha. so lift should account for weights, tank, and any other negatively bouyant equipment you carry.The exact reasoning slips my memory. It was several years ago that I attended the seminar. From my experience the guideline works. What one also has to take into consideration is the type of tank being used, which includes the weight of the gas inside. Up here we dive in cold water and many of us use use steel tanks. As an example, one of the guys had a BCD that had a 30 pound lift capacity. He uses 28 pounds of lead and a steel tank. With the BCD on a ST100 tank and fully inflated the unit sank. Therefore, he switched to a BCD that has a 40 pound lift capacity and has had no issues.
When diving in the tropics this is less of an issue, especially when using an AL tank, but the guideline does offer useful information in terms of lift capacity.
gotcha. so lift should account for weights, tank, and any other negatively bouyant equipment you carry.