Does a scooter count as 'redundant buoyancy'?

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!

bipolarbear

Registered
Messages
55
Reaction score
66
Location
Hong Kong
# of dives
100 - 199
I just finished up a dive in Philippines where one of the divers on the boat (not my buddy, not part of my dive team) had a long go at me about my 'lack' of redundant buoyancy.

It was a warm water dive, water temp around 30 degrees on the surface. 26 degrees at planned depth (80m). I don't dive in caves, and I don't dive cold water; almost all of my diving is in Philippines / Thailand / Chuuk Lagoon etc so I typically dive in either a 3 mil full, 3 mil shorty or just in tec shorts and a t-shirt. Today I was in the latter.

Run time for today was two hours. I invariably pad the deco on dives like this so told the boat to expect us to surface at two hours and fifteen with an SMB at around the 90 minute mark. A nice scooter dive along a wall at depths between 80m and 35m, then ascending up a gradual slope up to a shallow bay around 8m in depth where we would do our long 02 deco. I was diving with double AL80s of 15/50 (we don't use standard gasses here and there's a hard bottom at 80m), an AL80 of air, an AL80 of 50% (only about 3/4 full) and an AL40 of 02. We splashed at the deepest point and I I switched to my air stage as we came up to around the 45m mark.

Dive was magnificent and relaxed. After the initial rush of the deep wall, it was a very leisurely cruise up into the (relative) shallows. Plenty of gas, no issues, we dived the plan.

Back at the shop the 'antagonist' (who was in a dry-suit, but dived the same profile as we did albeit with a different team) was adamant that what I'd done was dangerous. He said that it's irresponsible to do dives like this without a dry-suit. I would usually tell him to eff off but he's a vastly more experienced diver than I am (tech instructor and many thousands of dives, against my 300).

I was diving with aluminum tanks, with a 60lb wing and a carbon back plate. I was definitely heavy with all that gas at the start of the dive, but I'd actually added a few KGs as a tail weight because I'm always concerned about being positively buoyant on the final stop if I had an emergency and ended up sucking my doubles dry. Even on this dive I clipped my almost empty air stage to my SMB line and sent it up once on 02 deco as it's unpleasantly floaty.

I always dive with a scooter. A serious scooter, a Suex that's serviced and maintained. Additionally, I carry two SMBs which can be used as alternative buoyancy in case of wing failure (and I've practised this with a simulated failed wing, beyond what was required in trimix classes). I almost always dive on sites with a hard bottom shallow enough where in the case of a wing failure and an inability to use my SMBs, I could drain my doubles without busting PO2 limits and crawl my way up to my next gas or (on a *really really bad day*) hypothetically ditch the harness and take deco tanks.

Anyway, long story short, was this guy right or does he just not like diving with a dude in shorts and a t-shirt? To my mind, I had two forms of redundant buoyancy (i) my scooter; and (ii) my two SMBs. To be clear, I think that if I was diving in places with no hard bottoms I would either invest in a dual bladder wine or just go dry-suit. Thoughts?
 
How would you use a scooter for buoyancy? Point it to the sky and go?
But if you're diving double Al80s with ditchable weight, your rig might be balanced. You can do a test: with full cylinders, empty your wing and see how much effort it takes to ascend.
Also, i wouldn't recommend double-bladder wings. Not necessary with a balanced rig, but just more that can go wrong.
 
How would you use a scooter for buoyancy? Point it to the sky and go?
But if you're diving double Al80s with ditchable weight, your rig might be balanced. You can do a test: with full cylinders, empty your wing and see how much effort it takes to ascend.
Also, i wouldn't recommend double-bladder wings. Not necessary with a balanced rig, but just more that can go wrong.
I mean, if my wing failed I can point my scooter to control my buoyancy. It has plenty of power, plenty of battery life, and could easily propel me upwards even on a dive with 3+ decos or stages.

I can swim up my doubles with a wing failure. I use stiff Jet fins and am relatively fit. But I suppose the concern is that if your wing failed at 10m during the descent on an Advanced Trimix-level dive, you wouldn't realise until you hit your inflator at the planned depth and I know there's no way I can swim up with full tanks in that configuration.

I understand the risk with double bladder wings which is why I have avoided them to date. If I did dive with one, I would of course dive with the second inflator valve disconnected.
 
I definitely wouldn’t consider a scooter “redundant” buoyancy. However, with Al80’s, I would consider the SMB as possible redundant buoyancy.
 
A scooter is in no way buoyancy.

I have a couple in 400 feet of water in the Gulf of Mexico that flooded on me. Just wave Bye Bye.
 
Until it floods and becomes an anchor.
In a real emergency I would ditch what I could do without. No equipment is worth my life or in other words: when I'am dead that equipment won't be of any use to me.

So the real question here is: at what depth do you plan to ditch what and can you still get up? If so, no problem as far as I'am concerned. I do not believe in strict protocols, but doing what works. A drysuit alone is no guarantee either you can make it to the surface with all your gear.
 
Lift bag. Smb, drysuit, 2 wings, working non flooded scooter. Ditching lead.
Are all options. To get out of trouble.
Any one of them can fail, if 2 fail at the same time... that can get interesting.


I do think you have done some thinking on the matter and sounds like some practice as well. You just need to know your options.

There is times I dive double lp72s with a shorty and I know I am heavy....
But I have options. My rule is always dive with a lift bag. No exception
 
Until it floods and becomes an anchor.
Obviously if it flooded I would let it go in an emergency. Then I would be left with my 2x SMBs for redundancy. At least on my view of the world. Which it seems is potentially not generally accepted so I may have to reconsider.
 
Lift bag. Smb, drysuit, 2 wings, working non flooded scooter. Ditching lead.
Are all options. To get out of trouble.
Any one of them can fail, if 2 fail at the same time... that can get interesting.


I do think you have done some thinking on the matter and sounds like some practice as well. You just need to know your options.

There is times I dive double lp72s with a shorty and I know I am heavy....
But I have options. My rule is always dive with a lift bag. No exception
I've never owned a lift bag and it sounds like I should look into one. The SMB approach is clunky. Can a lift bag be stowed in the pockets of tec shorts, or is it too big?
 

Back
Top Bottom