First dive with BP/W. Weighting question

[divezonescuba]

UTD makes a slightly positive tech style fin. I have to use them as for some reason I am foot heavy. I also have to use a lot of weight high to maintain horizontal trim. The fins help a lot.

I think Quattros are somewhat negative as our boats Divemaster once lost one on a rig.

 

[Dish]

While I may be misinformed, I believe that the OP is a new diver trying to work out his weight and trim with his new BP/W kit. I think that he needs to work on his form before he seeks out materiel solutions. He may find that working on proper form fixes his current leg heavy issue without buying new gear.

That said, lighter fins will help if form doesn't and I agree with @divezonescuba 's recommendation.

My 2 psi worth, YMMV.

 

[halocline]

He's definitely working on fine tuning his trim and weighting. Based on his comments it seems that he's further ahead than many new divers. I'm not sure what you mean exactly by "form" but I know that having appropriately buoyant fins is part of the weight distribution puzzle. Divers should be able to hold horizontal trim even with their legs extended. I know I can if I'm using the right fins. As an example, my trim in backmount doubles improved quite a bit when I switched to jets. I had good propulsion technique before and after the switch.

 

[Dish]

Yeah, maybe not the perfect word. I was referring to body, head, arm and leg positioning which can effect your horizontal trim. I re-read @Charred 's original post to make sure I hadn't dropped sync on his original concerns... one of which was "heavy legs". I know if I get lazy with my body positioning, I experience the same issue. In the end, I didn't need lighter fins to fix that problem, just mindful of my "form".

 

[boat sju]

Since you're talking "fine tuning", a 1# ankle weight on your tank valve may work for you.

 

[Charred]

I got back from my Cozumel trip this weekend. Again, my wife and I are new divers so we took a trip to dive dive dive to get as much experience as possible under our belts. We did 19 dives in 4.5 days.

By the afternoon of the second day I had weighting pretty spot on and trim just came naturally as soon as weighting resolved. I started the dives with 8 extra pounds. 2x2 in XS Scuba pockets on the cam bands and 4 total on a belt. The DM recommended I go in heavy at first because of the current and my brand new 3mm westuit. Every SS I checked my weighting and was heavy so I dropped 1 lb each dive until I had a 3 and 2 in my cam bands. I was probably still ~1 lb heavy because I was still negative at the SS but stayed with it because some dives had heavy current and you need to be able to occasionally drop a finger into the sand to keep with the group. In the end, I think 2x2lbs in my cam bands would be perfect. This is of course just like everyone said it would be. This also means I can ditch the weight and the wetsuit in the summer if I feel like diving in a rash guard.

I really cannot be more pleased with the leap of faith I took to jump into a BP/W. I really didn't have a mentor. I rigged it myself, tweaked it myself. Its not rocket science. By the third day, my wife said I was indistinguishable from the DM who was a cave diver in a Halcyon BP/W. The wing really accelerates you down the learning path. As soon as I got the trim worked out, I could nearly instantly helicopter kick and doing those made diving a dream. My wife also picked up a DSS BP/W and while she made zero effort to be horizontal, she had better trim than nearly all the other people on our dives except the DM. Both of us could do swimthroughs without silting it up and neither of us bounced off any corals the whole week.

The highlight of my trip was hovering effortlessly over the Santa Rosa Wall.

I could not be more thankful for all the wisdom on this site.

P.S. Both of us also used the 40 inch primary hose and 22 inch backup on a bungee and that advice was spot on as well.

 

[stuartv]

Every SS I checked my weighting and was heavy so I dropped 1 lb each dive until I had a 3 and 2 in my cam bands. I was probably still ~1 lb heavy...

That's all awesome to hear.

One question: Were you tracking your tank pressure at the SS versus the weight that you had?

An AL80 holds ~6 # of gas. That means, at 2000 psi, you have 4# of gas and at 1000, you have 2#.

If you want to be able to be neutral with an empty tank, then you need to be 2# heavy when you're at 1000psi.

There are people on SB that I have seen post comments to the effect of: "I always get out with at least xxx psi of gas left, so I weight myself to be neutral with an empty BCD and that much gas. I don't want to carry the extra weight that would correspond to having an empty tank, when I never actually breathe mine that low."

Some will even add comments like "if you have to stay down all the way to the last breath of your tank, the weight difference is minimal and you can manage it by controlling your breathing or finning a bit to stay down."

That's all fine if you understand the choices you're making and want to dive that way.

Personally, I want to be prepared for an eventuality that results in me NEEDING to stay at my safety stop for literally as long as possible (say, I got delayed on the bottom and incurred an unexpected deco obligation). If that happens, I will probably be feeling stressed and controlling my breathing will be even more difficult than usual. In that case, I want to be able to hold my safety stop EASILY, and all the way until I see less than 200 psi left in the tank or it starts getting hard to breathe. If that means being overweighted by 2 # at my normal safety stops, I am FINE with that.

 

[Charred]

They were dragging me out of the water

I was usually sub-500 psi. Since we were diving 4x a day, I was doing long safety stops and holding at 10 and then 5 ft while the rest of the people got in the boat.