How to (politely) advocate for more weight?

[NW Dive Dawg]

No. Your ability to descend is about the gravity pulling you down versus the water pushing you back up.

I disagree. The ability to descend, ascend or remain neutral is all about the actual weight and volume of displacement vs the weight and volume of the water you are displacing. Water does not "push you back up" .. unless its a result of an upwelling or other non normal event.

 

[johndiver999]

Perspective of an instructor who also works from time to time as a DM on charter boats:

As an instructor, I’d say:

—Being optimally weighted (neutral at the end of the dive) improves efficiency and control during the dive. If you are overweighted, you need extra air in your BC to stop your descent before you hit the bottom, and the tendency of that air to expand/compress in response to small variations in your depth will have overweighted divers relying on the inflate/purge buttons instead of controlling depth through breath control.

—Most divers who use more than expected amounts of weight could use less weight, often much less weight, if they did their weight checks while completely relaxed with slow breathing, no arm sculling, and no leg kicking. Most group OW classes do not take the time to get everyone relaxed enough to do an accurate check. (That’s one reason I focus on private/semi-private lessons and one reason the extra cost represents value to the customer.)


As a DM on a boat, my perspective is slightly different.

—I’m not going to conduct a buoyancy clinic in the context of an group excursion dive charter. If you present yourself as a certified diver with recent experience, I’m going to let you dive your dive unless you give me a reason to doubt you can do it safely.

—Although optimal weighting and lower air consumption rates are ideal, recreational diving is not a contest to see who can use the least lead or air. Carry the weight you need, use a tank with the air you need, and enjoy the dive. Eventually, the weight and air you need may decrease, either through practice or taking a PPB course, but don’t ruin today’s dive for yourself or your buddy by artificially accelerating the process.

—What you need theoretically and what you need today given your skill, experience and comfort with today’s conditions may be very different. Anxiety over more chop or less vis than you’re accustomed to may increase the amount of weight you need.

—I am much more concerned with the safety implications of uncontrolled ascents by underweighted divers than the negligible chance of a diver carrying too much weight to ascend. My biggest safety concern with a heavily weighted, high body fat customer is the climb out of the water.

—People are different, and I’ve been surprised in both directions by the amount of weight people need. My inclination is to give you what you ask for unless you ask for something crazy— and the warm water numbers you mentioned aren’t crazy.

I was with you.. until that bolded comment In my experience, people who are over weighted have the largest propensity to end up making an uncontrolled (or at least accelerated) ascent.

People that are underweighted in recreational diving are probably not going to get down.

However, we have seen many examples of less than highly skilled divers, being unable to manage a large bubble in the BC (due to excess ballast) and consequently, the last 20 feet of the ascent gets away from them.

I personally always carry a little more lead than I really need. Last weekend, I did a dive to 90 and just now realized (after looking at dive video) that I forgot to put on my weight belt which has about 6 or 8 lbs on it.

 

[Scraps]

I was with you.. until that bolded comment In my experience, people who are over weighted have the largest propensity to end up making an uncontrolled (or at least accelerated) ascent.

People that are underweighted in recreational diving are probably not going to get down.

However, we have seen many examples of less than highly skilled divers, being unable to manage a large bubble in the BC (due to excess ballast) and consequently, the last 20 feet of the ascent gets away from them.

I personally always carry a little more lead than I really need. Last weekend, I did a dive to 90 and just now realized (after looking at dive video) that I forgot to put on my weight belt which has about 6 or 8 lbs on it.

I agree that overweighted divers are more likely than divers as a whole to make an uncontrolled ascent. However, that propensity is a reflection of their inexperience, not the extra weight they carry.

I also agree that significantly underweighted divers pose no risk of rapid ascents because they can’t descend. However, slightly underweighted divers—the ones who are neutral at the start of the dive but light at the safety stop and the ones too embarrassed to ask for more weight once they’re in the water even though we advised them to do a weight check, so they pull themselves down the anchor line until the neoprene in their wetsuits compresses enough to permit them to descend (it happens more than you’d think)—are at risk.

As a practical matter, I think we view the situation similarly and for similar reasons.

 

[inquis]

Can trim impact your ability to descend?

Possibly. It's common for new divers to unconsciously kick slightly. If head up in such cases, it WILL take more lead to sink them. I've seen people swear up and down they don't... until they try this trick:

Cross your ankles as you start your descent.​

It may not make a difference in your case, but it might be an interesting experiment.

Another thing that is pretty common with newer divers is unknowingly keeping lungs a little fuller or breathing a little more rapidly. Making a conscious effort to relax and EXHALE as you vent the BC may also help. Again, I know it sounds obvious, but there may be a little anxiety at play.

 

[inquis]

breath it down to 400 -500 and then see if I can easily hover at 15-20 ft with no dry

If you find you're neutral before getting down to 500 psi, then add lead based on the amount over 500 psi. Air in your HP100 weighs 1.2 lbs per 500 psi. For example, if you're neutral at 1500 psi, you're underweighted by 2.4 lbs.

 

[BRT]

Are you absolutely sure? This would be very unusual, especially in Hawaii. Which dive shop?

No.

I don't think you are saying what you meant to say. At the beginning of a dive, you will be heavy, because you are carrying about 5 lbs more than you need at the end of the dive, to compensate for losing 5 lbs of air weight from the tank at the end of the dive.

I said precisely what I meant to say. You can descend at the start of a dive with less weight than you need to hold a safety stop at the end of a dive.

 

[inquis]

On your next dive, it might be worthwhile to carry a couple of 1 lb weights that you can get to easily. At the safety stop, you should be able to hold without air in the BC.

It may be difficult to get such small bricks. If so, it's easy to check from the other direction: when neutral at the stop with 500 psi, try to vent the BC. If a bunch of air comes out, drop a couple pounds for the next dive.

 

[Blackcrusader]

It’s a race to the bottom among some on SB to see how little lead they can dive with.

Yes and one of our newer members got stuck on an overhead from being underweighted... He was warned many times about diving underweighted and didn't listen. I dive with no wetsuit using 8kg. I often get told its too much. So I will put 4kg in a weight belt with no gear on and float at the surface. I float like a cork.

If I go down to 6kg I cannot stay at 5m on a safety stop with less than 50 bar without finning to stay down. I keep two 1kg weights handy as many times have found instabuddy divers underweighted at the safety stops. Don't want them having an uncontrolled ascent into a boat.

 

[clownfishsydney]

Back in 2011 our club went to New Zealand for a dive trip. First day on the boat the DM asked how much lead I needed. When I told him 14 lbs, he kept insisting I need another 6 lbs. Time after time I told him no, I did not. Finally, I told him to go and look at the release form I had completed and then come back. He never returned. Why? Because he would have seen that at that time I had completed 3,109 dives and realised I might actually know better than him how much I needed.

In the OP's case, I would have my log book with the weights written down to show. Hopefully they would accept this.

 

[tursiops]

I said precisely what I meant to say. You can descend at the start of a dive with less weight than you need to hold a safety stop at the end of a dive.

Ik, sorry, now I understand your statement.