Calculating weight loss vs weight belt

[keesmon]

Without doing the math (which seems impossible, given the variables) it seems like the difference would be negligible then?

 

[themagni]

If it helps at all, I went from 185 to 165 and my weighting went from 36# to 30#.

I did have to cut out a 1.5" wedge from the neck seal, and that works perfectly now.

 

[RJP]

Without doing the math (which seems impossible, given the variables) it seems like the difference would be negligible then?

Well the main question is really...

How badly over-weighted were you before you lost the weight. You can take off at least that much weight for sure.



My lead requirements in the pool (which I'm in almost weekly with students) was pin-point prior to trimming down, and I seem to have been able to shed 6lbs of lead in the pool.

 

[keesmon]

How badly over-weighted were you before you lost the weight. You can take off at least that much weight for sure.

That's always the question isn't it?
As a 1 to 2 dive trip per year diver, I always drop weights as the trip goes on, so I guess I'll start with plenty and see where I end up. Thanks!

 

[Cave Diver]

Start with what you used last year and do the wieght check at the end of the dive.
Only way to find out is to do a proper weight check with a near empty tank.

You may need less weight just being in better shape.
Your breathing rate may have changed as well.

Safer to dive with a couple extra pounds than a couple too few.

And this pretty well sums up what I was going to suggest.

 

[Mike Boswell]

Hi Keesmon,

I also lost a lot of weight and my lead loss was pretty dramatic. The wonderful and generous folks here on SB told me how to figure it out: Body fat is about ten percent less dense than water, so for every ten pounds of body fat you carry, you need an extra pound of lead to sink it.

For every ten pounds of fat you lose, you can take that pound of lead off your weightbelt. By your numbers you should be able to take 3.3 lbs of lead off, so I would start with dropping 2 lbs and then later see if you can drop two more.

If, as a result of losing weight, you also wear a smaller size exposure suit, the reduction in suit buoyancy will also cause a reduction in lead required.

However, if as a result of losing body fat, you need a thicker wetsuit for warmth, then you will have to add more lead to offset the added buoyancy.

 

[Mike Boswell]

Here is an average from a Google search:
one liter of male human muscle = 1.06 Kg
one liter of male human fat = 0.9 kg
one liter of pure water = 1.00 Kg (duh)
one liter of sea water = 1.025 Kg

Now, all you have to do is calculate the relative volume change to body fat, muscle, and lung capacity — or just jump in a swimming pool and adjust by about 2½%.

BTW: Congrats.

Male human fat? Is female fat different?

 

[Buoyant1]

I need to get on that bandwagon myself...the "offseason" wasn't too kind....that said....Easiest way is to schedule a check out like dive and just play with your weights...estimate what you think you'll want to drop and try it. Most OP's usually give you some time to check it out. (at least in my experience)

 

[BrotherBear]

Hi Keesmon,

I also lost a lot of weight and my lead loss was pretty dramatic. The wonderful and generous folks here on SB told me how to figure it out: Body fat is about ten percent less dense than water, so for every ten pounds of body fat you carry, you need an extra pound of lead to sink it.

For every ten pounds of fat you lose, you can take that pound of lead off your weightbelt. By your numbers you should be able to take 3.3 lbs of lead off, so I would start with dropping 2 lbs and then later see if you can drop two more.

If, as a result of losing weight, you also wear a smaller size exposure suit, the reduction in suit buoyancy will also cause a reduction in lead required.

I need to get on that bandwagon myself...the "offseason" wasn't too kind....that said....Easiest way is to schedule a check out like dive and just play with your weights...estimate what you think you'll want to drop and try it. Most OP's usually give you some time to check it out. (at least in my experience)

Looks like I'm going to need to add some lead too! Hopefully the changes to my equipment will help (going BP/W) offset the added buoyancy of my larger, um, body-integrated flotation device...

Male human fat? Is female fat different?

Yeah...female fat is considered hazmat as it reacts violently to open discussion!

 

[spectrum]

Without doing the math (which seems impossible, given the variables) it seems like the difference would be negligible then?

Looking at the number cited above reminds me of a rule of thumb saying 11 pounds of lost fat saves you a pound of lead. that lines up with the common thought of 2 pounds. Remember that as you loose fat you also loose displacement so it's almost a wash.

Keep your prior weight. Having the DM carry weight you might need is a bad idea. Have it on you and you can't forget or miss your connection. However before the dive brief your buddy that you will want to hand some weight off for a good weight check near the surface at the end of the dive.

Pete