BP/W for a very large man

Please register or login

Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

Benefits of registering include

  • Ability to post and comment on topics and discussions.
  • A Free photo gallery to share your dive photos with the world.
  • You can make this box go away

Joining is quick and easy. Log in or Register now!

MikadoWu

Contributor
Messages
371
Reaction score
119
Location
Florida
# of dives
200 - 499
Good Morning All,

I have only seen 1 VERY large person in my diving career. Do the rules change at all when fitting a 6'1" 450lbs man for a BP/W. Do you use a 40+lbs lift or the 32lbs works just fine? He mentioned it takes 26lbs of lead for him to sink.

I have never fitted a man this large before and just want to make sure I a, prepared for something unexpected.

Thanks,
 
Good Morning All,

I have only seen 1 VERY large person in my diving career. Do the rules change at all when fitting a 6'1" 450lbs man for a BP/W. Do you use a 40+lbs lift or the 32lbs works just fine? He mentioned it takes 26lbs of lead for him to sink.

I have never fitted a man this large before and just want to make sure I a, prepared for something unexpected.

Thanks,

A wing has to do 2 things. Compensate for changes in buoyancy *gas volume and suit compression*, and be able to float the rig itself when removed from the body. IF the guy has 26lbs of lead integrated into the rig, then you're going to need a 40lb wing. If that lead is on a belt, then you can get away with a ~30lb wing.

I would set the rig up as you would for any other diver spare the much longer harness. If this is a rental, you can make an extension waist belt strap, if it's for purchase, make sure you get an extra long piece of webbing, several feet longer at the least.
Get as much lead as you need to get the guy neutral on a belt. You want the body mostly neutral which will keep all of the extra lead out of the wing calculations but also make the rig tolerable for changing tanks. I can't stand integrated weight pouches, but especially can't stand them when they have a bucket of lead in them.
 
The main concern a larger person will have is the amount of lift when choosing a wing.

If they are wearing a wetsuit, particularly a thicker one 7mm+, as a robust person, they will need ballast (lead) to counter the buoyancy of their suit (and body), a larger body = more neoprene = more buoyancy to counter.

Is the 26lbs of lead needed to sink based on the thickest suit they plan to dive in? Is that with a plate or a standard jacket/vest style BCD? If the 26lbs is with a jacket/vest BCD they will most likely need slightly less due to the general lack of buoyant padding in a backplate system...plus you could subtract the weight of the plate from the amount of lead needed as well.

If 26lbs is the max amount of lead the person will be wearing and they are not going to be carrying a lot of gear then I think a 35lb wing would work...but the variables are full in-water weight of the tank they plan to use, plus the weight of any negatively buoyant gear (reg set, etc.).

Wings above 35lbs tend to be a bit wide for single tank diving and will taco around the tank during the dive when air is added to the wing. I recommend to be very selective about design when choosing a wing above 32lbs to 35lbs of lift and get one that has the narrowest profile as possible.

-Z
 
Really need more info but I’m having a hard time picturing any exposure protection in the 26 lb figure given, he is 4” shorter than me and out weighs me by, me.

for myself I use a 35lb VDH wing-in cold water drysuit and use the suit for buoyancy while diving.
 
The short version is, I do not have to much info yet. The man and I have known each other for 4 or 5 years through work, but only see each other maybe 6 times a year. We are both in the middle of projects and are planning to talk more in 2 weeks at our annual meeting. He felt shafted by if LDC, which is one of two reasons he stopped diving.

In my diving pro career, I have dealt with mostly athletes. Just want to make sure I do not miss asking a question.

Thanks all
 
One consideration for men of significant size - weight belts don't work well with their body shape. The more you can get integrated into the BPW the better - or failing that a weight harness instead of a belt.

Otherwise he'll spend a good portion of any dive trying to prevent the belt sliding down to his knees.
 
One consideration for men of significant size - weight belts don't work well with their body shape. The more you can get integrated into the BPW the better - or failing that a weight harness instead of a belt.

Otherwise he'll spend a good portion of any dive trying to prevent the belt sliding down to his knees.

I was thinking about that myself. The DUI weight harness would probably be a good choice. But I don’t know if it would fit as it comes from DUI. It holds up to 40lbs. Extra webbing might have to be added.
 
A wing has to do 2 things. Compensate for changes in buoyancy *gas volume and suit compression*, and be able to float the rig itself when removed from the body. IF the guy has 26lbs of lead integrated into the rig, then you're going to need a 40lb wing. If that lead is on a belt, then you can get away with a ~30lb wing.

I would set the rig up as you would for any other diver spare the much longer harness. If this is a rental, you can make an extension waist belt strap, if it's for purchase, make sure you get an extra long piece of webbing, several feet longer at the least.
Get as much lead as you need to get the guy neutral on a belt. You want the body mostly neutral which will keep all of the extra lead out of the wing calculations but also make the rig tolerable for changing tanks. I can't stand integrated weight pouches, but especially can't stand them when they have a bucket of lead in them.

Honest question, if the diver needs 26lbs to sink just himself with no exposure protection, then isn't that just getting the rig to net neutral? Does fat lose buoyancy at depth like a wetsuit?
 
Honest question, if the diver needs 26lbs to sink just himself with no exposure protection, then isn't that just getting the rig to net neutral? Does fat lose buoyancy at depth like a wetsuit?

fat is not compressible so it does not change at depth. You want the diver to be as neutral as possible without the rig so if they have to remove the rig, the risk of the diver popping up like a cork and the rig sinking like a brick is minimized.
 
One consideration for men of significant size - weight belts don't work well with their body shape. The more you can get integrated into the BPW the better - or failing that a weight harness instead of a belt.

Otherwise he'll spend a good portion of any dive trying to prevent the belt sliding down to his knees.

My guess is to measure the guy and go to Piranha for some custom webbing for the harness.
 
https://www.shearwater.com/products/peregrine/

Back
Top Bottom