General BP/W questions

[tbone1004]

I haven’t dove the skin suit since switching to steel tanks so I’m not sure, but going from AL to steel with current BC and 3mm I went from 14lbs to 6lbs of ballast, and in skin suit with AL tank used 10lbs. So would use 2lbs by that metric, but then adding a SS BP I may be overweight. I don’t wear lead with the intention of ditching it but would if the situation called for it. I’m just trying to assess potential risk(s) and possible solutions.

if those numbers are right, the Al plates are only 3-4lbs less negative than the steel. Obviously depending on the specific plates we are looking at. If you only use 2lbs by the math, then that IMO is not enough of an issue to warrant having to deal with a weight belt.

 

[kmarks]

if those numbers are right, the Al plates are only 3-4lbs less negative than the steel. Obviously depending on the specific plates we are looking at. If you only use 2lbs by the math, then that IMO is not enough of an issue to warrant having to deal with a weight belt.

I was thinking the same thing. An Al plate weighs about 2-3 lbs, and a SS plate weighs 5-6 (unless you get a double thickness plate). There is a 2-4 lb difference between the two. I decided on a 5.5 lb SS plate for myself instead of a 2 lb Al plate because I just don't see that as being enough of a difference to matter.

I sink faster than a small rock. In a neutrally buoyant jacket BC, in Caribbean salt water, with no wet suit and an Al80, I wear 4 lbs; with my 3/2 wet suit, 10 lbs. If I had gone with an aluminum plate, I would probably end up putting any additional 2-4 lb weight in a non-ditchable trim pocket, anyway.

 

[Brian Roebuck]

Ok thanks, obviously will take some fine tuning once I make the switch, just wanted to see what the best starting point would be for me.

 

[Brian G]

I feel that I should be able to get positively buoyant (or close to it) at the surface with a failed BC. For me, that would mean that I would not dive steel cylinders on a steel backplate with no wetsuit. That combo would put me at around -14 lbs (with my HP80 at -8 lbs and a SS backplate at -6 lbs) at the beginning of the dive. That's a little too negative for me.

With an HP100 you will start the dive about 7.5 lbs heavier than you end it, so if you find a gear combo that gets you neutral at your safety stop at the end of your dive with no wetsuit, you will be 7.5 lbs heavy at the beginning of it. That's not too bad. I carry an SMB that I could use for extra flotation if the BC failed. It would work for both -14 lbs and -7.5 lbs, so no difference there. 14 lbs is quite a bit to swim up though.

There are other factors of course. BCs rarely fail completely. Deploying the SMB from depth using a spool makes it more flexible. My SMB has a pull dump, so I could use it as a direct BC backup. There are a lot of options. A bit of practice might be a good idea (note to self).

Regards,
Brian

 

[2airishuman]

I am considering making the switch to BP/W but have a few questions. I currently have a Zeagle stiletto and use 6lbs with my 3mm full suit. What I’m mostly concerned with is, if I choose a SS BP and I’m not in my 3mm would I even need added weight and if not what would be the procedure if a “weight dump” situation occurred? Should I choose AL BP to keep some dumpable weight on a belt or in pockets? I live in SE Florida and will use a skin suit half the year while the water is warm and I don’t want to be overweighted and I also want to be safe.

I note you are relatively new to diving.

There are experienced divers who conclude that, given the specific facts of their particular situation, they can conduct a dive without ditchable weight. This is not a decision that should be made without considering all the possible problems that could occur.

Questions for you to ponder would include:
- Can you operate your cylinder valve during the dive? If you accidentally enter the water with the valve closed, and have no ditchable weight, will you be able to recover? How?
- Can you ditch your kit quickly and confidently? Would you be able to do so at the surface if you needed to do so to remain buoyant?
- Will you be able to swim up your rig if you have a BC failure toward the beginning of a dive? Could you control your descent on a wall dive in the event of BC failure?
- Are you skilled and confident enough to deal with, say, a ruptured BC, by adjusting your trim to keep the rip pointed down?

Some people have two backplates, one heavy one light. Just sayin'.

 

[johndiver999]

I disagree that having the ability to ditch ballast and rise to the surface has no value in recreational diving.

However, a steel plate is going to make the diver heavier than he needs to be (without a wetsuit). What benefit is provided by selecting a rig that has no droppable lead and REQUIRES that air be kept in the BC at all times (to remain neutral)? This represents an unnecessary vulnerability that is easy to eliminate or reduce (by using a less negative rig). It will also increase the drag of the BC since you are always carrying this "extra" air around.

Many fatalities occur when divers reach the surface and are unable to stay there. Often because they fail to inflate the BC and/or drop ballast. Why not configure your gear so you can at least rest on the surface, even though your BC has managed to fail or it is difficult to inflate because you ran out of air and may be stressed by this situation - making it hard to orally inflate the BC?

Another very real danger is a diver jumping in the water with the tank off and having a too heavy rig and nothing to ditch. I watched a diver almost not make it back due to that stupid and avoidable error, Having some easy to drop lead can be a solution to a variety of problems, most of which shouldn't arise - but they do happen.

I see very little logic to a recreational diver deliberately using a rig that is more negative than necessary and has zero droppable lead.

 

[Brian Roebuck]

These are all reasons I posed the question, yes I am relatively new to the sport, about 20 ocean dives in the last few months & a lot of skill practices in the pool to build muscle memory and to perform tasks so they’ll be second nature if needed. I like the idea of a BP/W (increased range of motion and modular) but don’t know many who dive them to get opinions on options and point out potential hazards. Safety is my first priority so I appreciate the highlighting of possibilities both positive and negative to help me properly choose my next rig.

 

[Streydog]

I am a fairly new diver and recently switched to a BPW. Not to long ago I came here asking questions because I was worried the wing (20LB) I bought might not be large enough. I received great advice and all was good.
I had been using a Brigade, a Ranger with a 34Lb bladder. Wearing a 2.5 MM with an AL 80 I used 8lbs and using a steel HP120 I used no weight, I was a little over weighted. I decided to go to a AL wing because all my diving is warm water and often HP120's. My first dive with the BPW was with and AL80. I tried 8LB's and I was under weighted, I really struggled to stay down. 10 LB's was perfect with my 2.5 mm. Using a HP 120 I am a little over weighted but not bad enough to force me to wear more rubber than I need to stay warm. My advice would be to get an AL if you will be diving a steel tank often. I don't understand the concept of adding weight so you can have ditchable weight.

 

[tbone1004]

@johndiver999 who says that ditchable weight makes you positive? That's not possible in a 3mm wetsuit or less with a 100cf steel tank because the tank is going to more than sink the wetsuit.

 

[johndiver999]

@johndiver999 who says that ditchable weight makes you positive? That's not possible in a 3mm wetsuit or less with a 100cf steel tank because the tank is going to more than sink the wetsuit.

What is it they say about trying to get out of a hole




"stop digging".