Trim issues - Rolling over bp/w + heavy tank

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!

CT-Rich

ScubaBoard Supporter
ScubaBoard Supporter
Messages
3,763
Reaction score
4,155
Location
Hamden, Connecticut
With 15l tank i have to add quite a bit if air into wing and adjust as i go. Ultimately i feel overweighted by the tank already so i feel like adding weight may not work.
The down side of the BP/W, especially with a steel tank, is the negative buoyancy. It isn’t a problem if you have an exposure suit that will require ballast anyway, but with just a rash guard, you are likely to be overweighted.
 

Rukkian

Contributor
Messages
117
Reaction score
72
Location
West Des Moines, Iowa
# of dives
50 - 99
With 15l tank i have to add quite a bit if air into wing and adjust as i go. Ultimately i feel overweighted by the tank already so i feel like adding weight may not work.

If you need a bunch of air in your bc with no weight besides your tank, and you are still turtling, it is probably not a good setup for you. What exposure suit are you using? If you are diving without exposure suit (warm water), then a large steel tank can be problematic. They are incredible for cold water, with thick wetsuits or dry suits, as you need extra weight, or side mounted.

As others have said, dropping the sta might help if you have one, as it removes weight from your back and also gets the tank closer to the bp. You could also check into a lighter alum or even soft bp. It may also just take getting used to it as well. You should not be rolling over, especially if you have lots of air in your bc, as a proper bp/w (or really any back inflate) is great for keeping you in trim.
 
OP
andrethediver

andrethediver

Contributor
Messages
560
Reaction score
17
Location
Philadelphia, PA
# of dives
500 - 999
Hi @andrethediver

Others have also asked, are you rolling side to side or is the BP&W with cylinder rolling/moving on your body?

I weight in the trim pockets, no problem. Did you ever have this problem when you were diving your Knighthawk?


I look forward to follow up.

I don’t remember having such issue with any of the BCDs. It may in fact be the lack of a wetsuit as i did not seem to have such imbalance while wearing new 5 mil suit in my last trip. I am rolled to one side and ultimately upside down with tank on the bottom and me above it looking at surface.
 
OP
andrethediver

andrethediver

Contributor
Messages
560
Reaction score
17
Location
Philadelphia, PA
# of dives
500 - 999
The down side of the BP/W, especially with a steel tank, is the negative buoyancy. It isn’t a problem if you have an exposure suit that will require ballast anyway, but with just a rash guard, you are likely to be overweighted.
This was 15L aluminum tank, still very heavy and although I always go for this tank if i can, the change this time around was no exposure protection beyond Apeks shorts.
 

rick00001967

Contributor
Scuba Instructor
Divemaster
Messages
2,034
Reaction score
1,060
Location
canada
# of dives
500 - 999
Unfortunately Eclipse wing requires STA.

i guess that one has no way for you run the tank straps withoout an sta. bummer.
 
OP
andrethediver

andrethediver

Contributor
Messages
560
Reaction score
17
Location
Philadelphia, PA
# of dives
500 - 999
As a point of discussion, IF you still have air in your wing at reserve tank pressure, you might be able to ditch the tank adapter. This moves the weight closer to your central axis yielding a reduced tendency to roll. There are soft (low profile) stabilizers available, and some people find their tank stable just with the pressure of the bands against the backplate alone. This does require your backplate have slots for the bands, of course, but most do these days.

ETA: if you ditch the STA but are then underweighted at reserve pressure, putting the needed weight in trim pockets on your belt will further reduce the tendency to roll.
No camband slots i BP or wing, system comes with and requires STA. perhaps they male CF adapter though.
 

lowwall

Contributor
Messages
2,249
Reaction score
2,587
Location
Chicago
# of dives
200 - 499
How much lead are you carrying and where is it placed?

When I've dived with a steel hp120 and my steel backplate (no STA), I didn't use any additional lead and it did feel tippy. But I was able to control it without issue.

I suspect the STA is what's making it difficult. Ultimately here's your choices (can be a combo).

- practice and learn to live with it
- put/move some lead to your front to counterbalance
- ditch the STA and get a wing with slots for the cam bands
- use a lighter/smaller tank, an HP100 is very nice
- if you are using a typical plate with a very pronounced bend, find a flatter plate that is meant just for single tanks. I'm not sure who makes these now other than the Freedom Plate which are currently out of stock.
 

CT-Rich

ScubaBoard Supporter
ScubaBoard Supporter
Messages
3,763
Reaction score
4,155
Location
Hamden, Connecticut
This was 15L aluminum tank, still very heavy and although I always go for this tank if i can, the change this time around was no exposure protection beyond Apeks shorts.
I am confused, I never heard of a 15 liter Aluminum tank. 15 l tanks are usually steel. Does it have a rounded bottom inside the boot or flat? If it is rounded, then it is steel. Flat would be Aluminum.
 
https://www.shearwater.com/products/peregrine/

Top Bottom