Question about Bouyancy

[Craig66]

I am wondering if anyone can tell me how much less weight I would need to add/remove if after achieving perfect weighting I now add a 1.5lb princeton microwave flash light as a primary and a UK 1.25 pound spare flashllight as a secondry. I am presuming that since the lights are made of plastic that presumably some but not all of the weight will be translated into usable weight thereby allowing me to take of some of my added weight. I am guestimating that between the two adding up to almost 3.5 pounds that I can take off about 1.5 - 2 pounds off of my BC.

One other question is how much weight would I need to account for the addition of a 3mm neoprene vest

Thanks

Craig

 

[rakkis]

Weight on land is meaningless for the question you're asking. What matters is buoyancy. Lights are generally made to be a bit negative underwater. Without knowing the buyoancy characteristics of these light, I'll guess that you shouldn't take any weight off (1 lbs tops).

 

[bperrybap]

One other question is how much weight would I need to account for the addition of a 3mm neoprene vest

Thanks

Craig

It would be hard to guess this.
What I've done is put the vest in a pool or hot tub and then
put weights on top of it until it sinks.
The amount of weight needed to make it sink is how much
extra you need.

--- bill

 

[Diver0001]

Craig,

With all due respect, you can't logic this stuff out (let alone calculate it) except in bandwidths. There's only one way to know for sure. You have to dive it.

R..

 

[fisherdvm]

Carry an extra 5 pounds of gravel in your vest, and dump them out one by one until you are neutral......

Seriously, you would want to be a little on the negative side if you are using aluminum tank. Mistake is made if you are on a deep dive, and required little weight at depth due to the compression on your suit. As your tank go empty, you might have a hard time maintaining your 15 ft safety stop if your suit expand as your tank becomes postively buyant.

I think it is an error for folks to try to trim too much weight off, you really need to calculate your weight requirement with a near empty aluminum tank at the surface. Most folks have more weight added with a full tank until they start to sink.... But really should add another 3 or 4 lbs for the empty tank at the end of the dive.

 

[GDI]

Have at it and have fun

http://www.genesisdiving.com/buoyancy.shtml