Safety stops in OW with no line - tips?

[dumpsterDiver]

1) You might want to be weighted neutral with 50bars at 5m with an empty BCD. That is 'sufficient' weighting for your needs. Many divers opt to exceed their minimum 'sufficiency' in weighting. That's a product of poor buoyancy control - but is to be expected with developing divers..

Why would anyone want to weight themselves like this? If they use all their air then, by definition, they are going to be positively bouyant and have to fight to stay down and as I explained, they are vulnerable to accidentally floating up into a propeller on a boat for example. We are not talking about just the weight of the air in the tank associated with 50 bars either... A thick wetsuit can expand a lot from 5 m to the surface.....So again, the diver would NOT want to be neutral with an empty BC at 15 ft!!!!

Boats (and their propellers -even when not spinning) are extremely dangerous! Being able to avoid floating up by having sufficent lead is an important consideration... This is such an obvious concept that the diver should be able to establish neutral bouyancy at any portion of the dive, I am amazed that we are even arguing this???? Is this really what you teach?

I stand by my comment that it is always better to have a little extra lead than too little. I never said to wear extra (unneeded lead) "for the heck of it".

 

[smellzlikefish]

"I stand by my comment that it is always better to have a little extra lead than too little."

Spoken like a true instructor.

I often dive a 5 mm and am weighted as described (neutral at 5m and 50 bar) and can report none of the issues you list. The only time I recall ever feeling underweighted was recently when I mistakenly put on 6 lbs. of weight instead of my usual 7. The fact is, you have more than enough buoyancy variation just from the air in your lungs to compensate for the wetsuit expansion or breathing a tank down.

Even with a few extra pounds, any diver lacking in buoyancy skills is subject to being propped and/or smacking the underside of a boat due to an uncontrolled ascent. I find the most difficult concept for newish divers is proper positioning to empty a BC completely. This is especially hazardous on the ascent. If you teach proper weighting, there is less to no air in the BC to begin with and thus less air to expand on the way up and cause issues with a boat.

That said, I understand why you teach overweighting. Newbie divers just aren't proficient enough to know what neutral buoyancy feels like so you give them plenty so they can sink knowing that the BC will float them back. As we mature as divers, though, trimming the excess weight from OW back is a very necessary adjustment.​

 

[dumpsterDiver]

"I stand by my comment that it is always better to have a little extra lead than too little."

Spoken like a true instructor.

I often dive a 5 mm and am weighted as described (neutral at 5m and 50 bar) and can report none of the issues you list. The only time I recall ever feeling underweighted was recently when I mistakenly put on 6 lbs. of weight instead of my usual 7. The fact is, you have more than enough buoyancy variation just from the air in your lungs to compensate for the wetsuit expansion or breathing a tank down.

Even with a few extra pounds, any diver lacking in buoyancy skills is subject to being propped and/or smacking the underside of a boat due to an uncontrolled ascent. I find the most difficult concept for newish divers is proper positioning to empty a BC completely. This is especially hazardous on the ascent. If you teach proper weighting, there is less to no air in the BC to begin with and thus less air to expand on the way up and cause issues with a boat.

That said, I understand why you teach overweighting. Newbie divers just aren't proficient enough to know what neutral buoyancy feels like so you give them plenty so they can sink knowing that the BC will float them back. As we mature as divers, though, trimming the excess weight from OW back is a very necessary adjustment.​

Attacking dive instructors now LOL... You second bolded comment makes me wonder if you really have any clue about what you are talking about. Empty the Bc for the ascent? Who taught you that little gem?

The amount of air in the BC should be modified for all portions of the dive so that the diver is close to neutral. Beginning an ascent in cold water, with a thick suit from just 60 or 80 feet, will require a lot of air in the BC in order to do it in a close to neutral condition.

 

[DevonDiver]

Why would anyone want to weight themselves like this? If they use all their air then, by definition, they are going to be positively bouyant and have to fight to stay down...

If they use all their air.... they'll not be doing a stop anyway, huh?

We are talking about novice divers... not technical divers. There's no issue with obligatory stops. If a novice diver was below their minimum reserve, conducting a voluntary safety stop, then they wouldn't need to maintain depth. I don't teach divers to 'fight' to stay down in those circumstances... it'd do more harm than good.

We are not talking about just the weight of the air in the tank associated with 50 bars either... A thick wetsuit can expand a lot from 5 m to the surface.....So again, the diver would NOT want to be neutral with an empty BC at 15 ft!!!!

Which is why the check is conducted at 5m...so that exposure suit buoyancy variation can be factored into the calculations. Also I don't teach the check to be done with 50bar/500psi... I teach it with a "nearly empty" tank... typically 20bar. That's 30bar below anything they should ever have to deal with.

Yes, a thick wetsuit can expand. How much buoyancy is gained from 5m to the surface? A couple of lbs. Well within the diver's range to accommodate using breathing control during the short (1 min) ascent from stop to surface.

Again... I will restate - the biggest problem with divers failing to control buoyancy in the shallows is caused by substantial excess/surplus air in the BCD which expands greatly in the shallowest depths. The only times I've ever seen divers "fight" to stay on a stop is when they've got too much air in the BCD and weren't effective at dumping it all. In every case, my intervention as remedied the problem for them (by dumping from their BCD effectively).

Boats (and their propellers -even when not spinning) are extremely dangerous! Being able to avoid floating up by having sufficent lead is an important consideration... This is such an obvious concept that the diver should be able to establish neutral bouyancy at any portion of the dive, I am amazed that we are even arguing this???? Is this really what you teach?

In what way am I not advocating the establishment of neutral buoyancy at any portion of the dive?

As I said... the biggest problem with uncontrolled ascents is over-weighting...and the consequent air-expansion of surplus air volume in the BCD. THAT is what novice divers find hard to control. THAT is what causes them to hit the surface without intention. THAT is what causes a danger from boat collision, lung over-expansion and DCS.

I stand by my comment that it is always better to have a little extra lead than too little. I never said to wear extra (unneeded lead) "for the heck of it".

Same thing.

A diver needs sufficient lead to enable neutral buoyancy at the point in the dive when they are most buoyant. That point occurs when the cylinder is most empty and the exposure protection is most expanded towards its original volume. To identify their requirements AT THAT POINT, the diver should replicate those circumstances and adjust their weighting accordingly.

If the diver then chooses to add more weight... it is surplus and serves no purpose, other than to account for a fear and/or misunderstanding of their requirements. It may seem intuitive to add surplus weight to ease buoyancy control... but in actual fact (in actual science... in math... in gas physics) it is an ineffective solution that only serves to make buoyancy control harder.

I see divers every day of my life. I see the fun divers who struggle with buoyancy - they are always over-weighted. I know that because I am pro-active in helping them resolve their problems - and intelligently reducing their weighting achieves results and positive feedback from the divers concerned. I train my own student divers to achieve proper weighting (neutral with nearly empty cylinder at 5m). I don't see them having problems with buoyancy. That's pretty definitive for me.

 

[dumpsterDiver]

A thick suit expands a lot from 5 meters to the surface. Not sure if it is just a few lbs, it sure seems like once I kick down to 15 feet or so, the suit is crushed some and my descent is easier.

I prefer to have a diver neutral at ZERO feet with ZERO air in the tank and if they want to add 2 lbs to hang under an SMB, that is fine as well.

I agree that most divers wear too much lead and any extra lead makes ascents and bouyancy control more difficult.

I just sounds like the definition of "extra" is different.

 

[smellzlikefish]

"Attacking dive instructors now LOL..."

Attacking is a bit strong, but there are certainly bad habits (such as severe overweighting) that are taught in OW that need refinement. I am not an instructor, but I certainly see why it is done like it is initially.

"You second bolded comment makes me wonder if you really have any clue about what you are talking about. Empty the Bc for the ascent?"

We are talking about people who may or may not remember to empty the air from their BC on ascent and again, a lot of students leave OW class unable to properly position themselves such that the air escapes.

"Beginning an ascent in cold water, with a thick suit from just 60 or 80 feet, will require a lot of air in the BC in order to do it in a close to neutral condition."

The OP stated they were diving in tropical waters where significantly less to no air is required to achieve neutral buoyancy at depth. Unless of course they are carrying an extra 10 lbs. of lead. ​

 

[smellzlikefish]

Sorry for the late post, DD posted as I was typing.

 

[Hatul]

Here in California we have kelp, which is great for holding a safety stop. After the stop I use the kelp to slowly ease my way to the surface.

 

[Mantra]

Hey all.

Thanks again to everyone for their thoughts. This has turned into a much richer and more interesting discussion than I could have hoped for. I'm actually finding it very useful to overhear experienced folk having a polite disagreement.

Someone else recomended your buoyancy masterclass posts, DevonDiver, and I have found them really useful. In the third installment of the series

Scuba Buoyancy Masterclass 3of9 - Achieving Great Buoyancy Control -Scuba Tech Philippines

you set some objectives for Novice, Internediate and Advanced divers. That was useful to know what skills I should focus on, and in what order.

I guess, just to feed back to the thread, I will keep focused on slowly growing my skills. I was indeed taught in an overweighted environment, and this thread has really teased out the nuances of what that means for me. Awesome work, everyone.

Cheers.

 

[Ayisha]

Here in California we have kelp, which is great for holding a safety stop. After the stop I use the kelp to slowly ease my way to the surface.

Hatul, I hope that was a joke. You are not supposed to hold the kelp or ease your way to the surface with it. It is a living, somewhat delicate being. Neutral buoyancy and control of your position at all times are key!