BCD lift requirements and so many gear choice variables

[scuba_divo]

I'm hoping SB can help me sort some things out. I've read a lot of posts here about calculating BCD lift requirements, but there appear to be two distinct schools of thought on the subject.

But first, some context: I'm about 6'2" (186.5cm), 305lbs (139kg). I'm overweight, rather than muscular. I'm returning to diving after more than 10 years away. My ultimate goal is to get set up for cold water diving most likely in a 2-piece 7mm full suit with a hooded vest or perhaps a semidry like the Hollis Neotek 8/7/6. I'm an expat living in South Korea where sourcing gear in my size (retail/rental) has been impossible. Gear requirements are further complicated by Korea having 2 distinct dive zones. I'd like to stay flexible enough for cold water diving on the south & east coasts and for warm water diving around Jeju so I can dive as much of the year as possible.

Basically, I can't dive here until I provide my own suit and BC at a minimum. I'm fairly certain that I want to go with a BP/W system as it offers many positives for my situation. That being said, the two schools of thought on lift requirements seem to be that:

1. Your wing needs to compensate for two specific things: loss of suit buoyancy at depth, and the change in tank buoyancy from start to finish. This school tends to recommend much smaller lift requirements.
2. Your rig needs to be able to float itself at the surface with any integrated weights attached. This tends to dictate much larger lift requirements, especially in my case.

According to both the "10% body weight + 12lb. for cold, saltwater diving" rule of thumb and the divebuddy online weight calculation tool, I would be required to wear more than 40lb. of ballast for the cold water diving I'm looking at doing.

My LDS back in Canada, where I may end up pursuing training due to the lack of English options in Korea, wants integrated weights and a rig that will float itself at the surface. That would take me to a 44~45lb. lift rig. Most BP/W divers on SB seem to think that's outrageous, but I'll need to take the LDS's thoughts into account if I want to do training with them. They want me to go with something like a Zeagle Ranger (LTD) with 44lb. of lift. That looks fine, but I want to remain travel ready, and the Ranger is big and bulky. At this point my head is just starting to spin with all the variables. I need to start finding clarity on these issues so that I can move forward and get on with diving. Any help sorting this through would be greatly appreciated. Is some of the confusion just coming from different advice for BP/W vs. Jacket/Vest style BCDs?

 

[luscioman]

So my disclaimer is I dont dive cold water and I have never used more than a 5mil. With that being said you know that 90%+ of the advice that will be given is to go with a BP/W over a Jacket/Vest. Being so remote if you have an issue with any component of a BP/W it will be much easier to repair that one piece as well. I personally dive an Apeks WTX-D40 wing. I have the bigger wing due to some specific requirements i have when sometimes working as a DM. I dont feel that the size of the wing gets in the way.

The group on this board is very resourceful and will probably be able to give you suggestions on where to get gear.

 

[kmarks]

People on ScubaBoard will tell you it is outrageous to use a 45lb wing if you don't need it because it will be big, bulky, and cause a lot of drag underwater. But for your size (and admission that you are overweight and not a bodybuilder), you are probably quite the natural floater. If you need to put all of your weight on your rig and still have it float at the surface, you'll need a big wing. It's not unusual for very large divers to carry 40+ lbs.

It would be better if you distribute your weight, some on the rig (a steel plate, ditchable integrated pockets, trim pockets on the cam bands) and some on a belt. If your LDS is telling you everything needs to be ditchable, integrated and you aren't allowed to wear a belt, you need to find a new shop to train with. Integrated weights aren't somehow magical and safer than being properly weighted in any other manner.

Online lift calculators will never be more than guidance, so take them with a boulder of salt. I just checked the divebuddy one you linked to and it doesn't work well for me at all. It suggests I need 1.5-2x what I actually have carried for weight, but I sink faster than most rocks, so I'm atypical.

 

[scuba_divo]

If your LDS is telling you everything needs to be ditchable, integrated and you aren't allowed to wear a belt, you need to find a new shop to train with.

Hmmm. I should clarify. An instructor friend of mine strongly recommended integrated weights for comfort. I guess the store isn't actually demanding it. They do want it to float all my gear at the surface though.

 

[scuba_divo]

you are probably quite the natural floater

Yeah, I'm working from the assumption that I'll float like a helium balloon.

 

[kmarks]

Hmmm. I should clarify. An instructor friend of mine strongly recommended integrated weights for comfort. I guess the store isn't actually demanding it. They do want it to float all my gear at the surface though.

"Integrated weights for comfort" is a very individual thing. I have a trim pocket on my upper cam band that I put a few lbs in, but I carry the rest on a quick release rubber free dive belt. I have only ever used integrated pockets with the jacket BCs I've used for training and I don't particularly care for it. Any movement on the diver's part can result in the weights rolling and shifting in the pockets if they aren't jammed full, whereas my belt doesn't move. Some people hate wearing belts, though.

 

[scuba_divo]

Some people hate wearing belts, though.

I guess my concern with a belt would be, "where do all these belts go?" Don't the BP/W harness waist belt and the weight belt interfere with each other?

One of the pros of the BP/W for me is definitely the option to use a 6mm SS heavy plate and various trim weights on cam bands.

 

[hammet]

I'm gonna say you probably burn through air faster so a steel tank (hp 100 or hp 120) would give you more weight and more air.

 

[scuba_divo]

I'm gonna say you probably burn through air faster so a steel tank (hp 100 or hp 120) would give you more weight and more air.

That was definitely an issue when I was doing my OW before. I'll need to see what's commonly available in Korea once I get connected with a couple of LDSs. Others have recommended that I even try to find 133s or move on to doubles as fast as possible.

 

[jadairiii]

40/45 wing would be perfect for you. Halcyon/DSS/Apeks (not a fan of the Apeks)/Oxycheq, any of them.

Figure you are diving wet, in recreational limits so you wet suit is not going to crush that much. Plus, weight yourself with the SS backplate and a keel weight then put just a tad of weight on a belt that you can ditch and you are good to go.