BC lift vs weight

[rockie_diver]

How do you determine if a bc has enough lift? For example, my AVID BC is an extra large and has 36 pound of lift. If I use my 6.5mm farmer john & shorty, I dive with 36 pounds of weight. Is this enough lift? Is there a rule of thumb that is used to determing bc lift?
Thanks
The Rockie_diver

 

[Diver0001]

How do you determine if a bc has enough lift? For example, my AVID BC is an extra large and has 36 pound of lift. If I use my 6.5mm farmer john & shorty, I dive with 36 pounds of weight. Is this enough lift? Is there a rule of thumb that is used to determing bc lift?
Thanks
The Rockie_diver

I think a good rule of thumb is that your BCD shoud be able to float all of your gear plus your weights. In your case, assuming you have an AL-80 for a tank then I would expect you to need 36 (weight belt) + 4 (tank) + 5 (give or take - accessories) or about 45lbs.

With the 6mm suit 36lbs will be enough as long as you keep your kit on but if for some reason you need to take off your kit on the surface you'll need to jettison your weight belt.

R..

 

[scubatoys]

Well, a couple of thoughts here... When I'm diving with a lot of weight, I split it up... some on a belt, some in the BC. That way nothing is so heavy that it's a pain to move. The other quick note here might be are you sure you need 36 lbs?? If I wear my XXL 7 Mil Farmer John, I'm doing about 26 lbs... So I'll put 10 on a belt. That gives me 16 in the BC which has 35 lbs of lift (Zeagle Brigade) so no problem there, and with that heavy suit, I'm still very buoyant wearing the 10 lbs.

 

[DA Aquamaster]

With an XXL 7mm semi-dry and 3/5mm hooded vest I am diving with 22 lbs. This increases to 26 lbs with a 7mm neoprene drysuit. My first thought is that 36 lbs may be a bit much for the suit you are wearing and I'd double check to ensure you are not overweighted. An XL Avid should be able to hold 30 lbs of weight split between the weight pockets and trim pockets, and in most cases that should be enough.

As for bouyancy:

1) Your weight integrated BC needs to be able to float your equipment and weight at the surface as it increases your exit options. With 30 lbs of weight and a full AL 80, (or less weight and a more negtively bouyant steel tank) a regulator this going to be about all a 36 lb BC can do.

2) A second requirement is that your BC be able to float you comfortably on the surface. If the BC can do #1 however, number 2 is generally a given as long as you also do not have more weight on a weight belt. This also gets subjective as some people are happy floating chin deep in the water and breathing through a snorkel. Others, particularly in ough water, prefer to get their whole head out of the water as well as an inch or 2 of their shoulders. In that case, 40-45 lbs is often the minimum for a cold water equipped diver.

3) You also need to have enough lift on the bottom to keep you neutral. This is normally the least demanding reqquirement for a single tank diver and 36 lbs is more than enough even with a thick wet suit.

 

[rockie_diver]

First, let me thank you for your replies and to apologize for not replying sooner. It seems as if I might be wearing to much weight, but when I do a buoyancy check 36 pounds is what I require. What I did do, at the end of last season, was to flood the suit. In other words, I unzipped the shorty and pulled on the farmer john which allowed water to flood the interior of the suit and that made me considerably more negative. That cold water really does wake you up.

Now the suit generally does keep me toasty. Could it be that I am not getting enough water into the suit so I float unless I over weight myself?

Rockie_diver

With an XXL 7mm semi-dry and 3/5mm hooded vest I am diving with 22 lbs. This increases to 26 lbs with a 7mm neoprene drysuit. My first thought is that 36 lbs may be a bit much for the suit you are wearing and I'd double check to ensure you are not overweighted. An XL Avid should be able to hold 30 lbs of weight split between the weight pockets and trim pockets, and in most cases that should be enough.

As for bouyancy:

1) Your weight integrated BC needs to be able to float your equipment and weight at the surface as it increases your exit options. With 30 lbs of weight and a full AL 80, (or less weight and a more negtively bouyant steel tank) a regulator this going to be about all a 36 lb BC can do.

2) A second requirement is that your BC be able to float you comfortably on the surface. If the BC can do #1 however, number 2 is generally a given as long as you also do not have more weight on a weight belt. This also gets subjective as some people are happy floating chin deep in the water and breathing through a snorkel. Others, particularly in ough water, prefer to get their whole head out of the water as well as an inch or 2 of their shoulders. In that case, 40-45 lbs is often the minimum for a cold water equipped diver.

3) You also need to have enough lift on the bottom to keep you neutral. This is normally the least demanding reqquirement for a single tank diver and 36 lbs is more than enough even with a thick wet suit.

 

[StSomewhere]

Now the suit generally does keep me toasty. Could it be that I am not getting enough water into the suit so I float unless I over weight myself?

The thing is, by definition water is neutrally bouyant. Adding water inside your suit doesn't make you more or less bouyant. My guess would be that by adding water between the layers you might be releasing whatever air might be trapped?