Horrible Divers Everywhere?

[Colliam7]

I never understood the idea that a jacket BC tends towards bad trim. I mean, if you're underwater (and not over-weighted), there should be very little air in the BC, so the bubble shouldn't affect your trim. So if its not the bubble, its not really the BC at issue.

So its really bad weighting that causes bad trim. In any BC, if you dont have your weights balanced, you will be in bad trim. True, w/ a BPW, you are likely to automatically be more balanced, just by the nature of a BPW. With a jacket, you will likely need trim weights. I used to dive a jacket BC, and it trimmed out fine, as long as I had weight in the trim pockets.

. . . I think its not accurate to criticize them for "causing bad trim." Bad weighting causes bad trim, not any style of BC.

YES!! You have stated it very well.

A jacket-style BCD, in itself, does NOT cause 'bad trim'. Divers need to be aware of their trim irrespective of what BCD they are using, and adjust their placement weight, accordingly. We spend a reasonable amount of time in OW classes on helping divers determine how much weight (total) they need. Unfortunately, we still do not give sufficient emphasis to the distribution of that weight, and many divers continue to focus only on the total amount and not where it is distributed.

Having said that, use of a fabric BCD, whether it be a jacket or a back-inflation unit, may make the issue more problematic, IF the diver is not aware of the physics involved. That doesn't mean the BCD causes bad trim, rather it adds a factor that the diver needs to consider.

Divers differ in their physiologic buoyancy characteristics. But, one thing that remains relatively constant is the location of their physiologic center of lift - the thorax (lungs). Think about what happens when you do a fin pivot. Most divers 'pivot' on the tips of their fins, while their upper body - their physiologic center of lift - rises and falls with their breathing. One of the advantages of a metal BP/W is that it also places weight in a position adjacent to this center of lift. Conversely, using a (positively buoyant) fabric BCD, whether it is a jacket style or a back-inflate model, places additional buoyancy (lift) in the area of physiologic lift. Divers add weight to offset BOTH their inherent buoyancy, AND the inherent buoyancy of their equipment - their exposure suit, and their positively buoyant fabric BCD in particular. Where is that weight positioned? Usually 'below' their physiologic center of lift - e.g. adjacent to their waist rather than adjacent to their center of lift. This is true irrespective of whether the weight is placed on a belt, or in the integrated weight pockets. So, underwater, their upper body is more buoyant than their lower body, and their trim is leg down. Divers whose legs / feet are more buoyant may not exhibit the 'foot down' tendency to the same extent. Maintaining horizontal trim is possibly a bit easier for them. Divers who have very negatively buoyant legs have more of a challenge.

Equipment manufacturers recognized this issue some time ago, and began placing trim pockets on many fabric BCDs - back-inflation and jacket units alike. (I would like to see the trim pockets placed even a bit higher than they usually are, but that is a personal preference.) Unfortunately, those same manufacturers in more than a few cases still add more padding to BCDs than is necessary. Not only does that add to the positive buoyancy of the upper body, it requires divers to add more weight, below the center of lift, to compensate. And, equally unfortunate is the fact that more than a few divers, who purchase BCDs with trim pockets, do not use them to maximum benefit - e.g. a diver needs 16 lbs of weight and puts it all in the integrated weight pockets. Or, that diver puts 12 lbs in the integrated weight pockets, or on a belt - below their center of lift - and only 4 in the trim pockets.

None of this means that the equipment is 'bad', or is causing the trim problem. Nor, does it mean that the divers are unskilled, or uncaring. It is disconcerting to see divers struggle with their gear, or somehow use their gear an an excuse for poor buoyancy control and bad trim. That is more often a matter of ignorance and inexperience, which can be corrected, and not necessarily a bad attitude which is often harder to address..

 

[ScubaWithTurk]

(I would like to see the trim pockets placed even a bit higher than they usually are, but that is a personal preference.) Unfortunately, those same manufacturers in more than a few cases still add more padding to BCDs than is necessary.

These are key points that I totally agree with. I never understood putting trim pockets in BCDs as low as I see many of them. I also do not understand the excess padding we see on BCDs. It is unnecessary and causes more problems than it fixes. Actually, it has zero benefit as the gear isn't uncomfortable without padding. I wish manufacturers would begin to design better gear with the recreational vacation diver in mind. Better trim pocket placement and no or very little padding.

 

[happy-diver]

When I was learning, the language was to be in trim (horizontal) when fining. 45 deg. was acceptable when not fining as long as you were neutral and not fining to stay in place. Apart from the few shore dives we did infrequently, most of our dives were from small fisherman's boat which were not anchored, so we had to from day one learn how to be neutral at our safety stops.
Through exposure here though, I saw the merits of being horizontal all the time especially since I'm the type of diver that don't like touch anything intentionally and especially accidentally. I am horizontal all the time, but it does hurt my neck when I angle my head to look straight forward for too long. That makes sense though as it would be like you standing up and looking straight up into the sky for extended periods. That's just not a natural position for the neck to be in. Since it is now difficult for me to be in any other position other than horizontal, I mostly keep my head at 45 deg, but even with that I still experience some pain after a couple of dives. Some people may have this issue (I've seen others post here saying so), so may choose 45 deg. trim when not moving.

Smart post
Ain't that a fact about the neck, especially in cooler climes but it does sort of ease up with time
sort of, you really don't have to bend your neck back much once trim becomes second nature.

Mate, my head is mainly straight looking down or like you say 45 degrees, is easy after the 90 degrees
and at the speed I'm going there's not going to be much damage when I crash my head into something

 

[Danseur]

That's my plan with the kids for Christmas this year. I wanted to try and get Trace to do it, but he's MIA.

Trace is hurt, badly. Call/Text/Mail something...

DM me as needed.

 

[Diving Dubai]

My weighting is fine. I'm assuming it to have been the location of weights because my fins (jets) are negative, and in a jacket style you only have so many options of where to put them, unless you are adding trim pockets. It has nothing to do with the weighting (solely the weighting I should say), it's the location.

Body posture is the most important thing. People use weight placement to try to correct bad habits, rather than fix the bad habit itself.

Case in point: AoW diver last weekend. total of 9 dives when she started. Having to use rental BCD which because of her body shape was less then perfect fit. No integrated weight, no trim pockets just a weight belt.

Weight check before the start of the first dive, after that no weighting adjustments or moving stuff around nonsense.

Each dive she had to make visual descents and ascents in "blue water" safety stops using line and computer as visual references - no physical contacts, PPB dive in 15' (4.5m) water over a reef that has urchins. All without real issues Corrections to trim and buoyancy were all through being taught posture and correct breathing

I'm not a super instructor and don't have any magical powers

Equipment isn't a solution to skills issues

Yes she will buy a wing, but more because she's "well endowed" and it better suits her rather than being something to correct poor skills.

 

[BlueTrin]

To OP (@rob.mwpropane) at the moment watch out for block of concretes at BHB:
https://www.facebook.com/291908803047/posts/10157688234788048?d=n&sfns=mo
Construction Warning at Blue Heron Bridge

DIVERS BEWARE!

The boat channel walls are under repair on the West Bridge span. There is no warning posted below although the bright yellow pollution containment barrier is visible to the shore. A sign above water advises a 50' distance but one cannot see that from below.

BE AWARE that it is extremely dangerous to swim in the passage between the bridge pilings and the boat channel pilings during this repair phase. This video shows enormous chunks of concrete that have dropped from above. Any one of these might have been fatal to a diver below.

may hurt you more than a diver scrapping the bottom

 

[annasea]

Trace is hurt, badly. Call/Text/Mail something...

DM me as needed.

Thanks for sharing this and encouraging people to contact Trace. I've forwarded this info to the appropriate people.

 

[PBcatfish]

There's a patchy reef line in 26-35 that runs for miles from Broward to Palm Beach County.

Yea, but access to it is pretty spotty. There is a lot of private property in the area. If you don't have a boat, then your options are limited.

I wanted to kayak fish in front of Trump's place. The closest spot I could find to park & get beach access was miles away. Before I got the kayak down to where I wanted to be, it was time to go back or else the parking meter would run out.

 

[PBcatfish]

Back to the original subject of BHB -

I know that place pretty well. I fish there. I dive there. I launch boats there. I've been going there for years.

That place is a trampled upon mess right now. It’s also been heavily depleted by commercial slurp gun fishing for exotics.

Any day of the week, if you go there at high tide (when the water is clean), you will see lots of dive flags. It gets a lot of tourist traffic. Apparently, diving there has been advertised as a destination & people go there for vacation.

Scuba classes are another source of the trampling. I recently inquired at a local scuba shop about getting a basic certification for a friend. Their standard package deal included 2 pool dives & 2 BHB dives for the checkout. That guarantees that people without well developed skills will be there on a regular basis.

The traffic there is so heavy, that if you go to a local scuba shop an hour or two after high tide, there is a good chance that they will not be able to fill HP tanks to full pressure because the high number of bridge divers that hits them after high tide usually drags the shop’s house bank down below the fill pressure of modern steel tanks.

Near the bridge, they have signs posted now that prevent people from collecting marine specimens in the protected area, but that cow is already out of the barn & the biodiversity in the area is not what it used to be.

…& a bunch of low-rent liveaboards are anchored up in the area.

…& the boat traffic in the channel on the edge of the scuba trail is heavy, especially on weekends.

None of these factors are healthy for the aquatic environment, but somehow, that place still survives & still has some interesting things to look at. It’s a well worn playground for sure, but it’s not dead yet. It’s resilience surprises me sometimes.

I’ll take someone from out of town there on a first dive of the visit, because it’s an easy shore-entry dive & an easy spot to confirm their skill set in shallow, somewhat-protected waters, but after they prove their skills, I have other local places of interest to take them. As Yogi Berra once said – nobody goes there anymore, it’s too crowded.

 

[Doc Harry]

Bad divers are not limited to tourist spots like BHB. I've been on 10-day liveaboards, and saw utterly horrible divers there too. The dive masters on the boats are afraid to say anything to the customers because they want to keep their jobs. I've had dinner ashore with more than one liveaboard owner to discuss these matters. Specifically, the DM must take action to protect the reef from bad divers, and the boat owner has to support the DMs and not fire them when they do so..