Why the hate for weights on AL80s?

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kommisarrex

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I recently dived with AL80s sidemount—usually I use steels. Was pretty straightforward switching the cylinder snap lower on the waist band as they got floaty, but my legs started to come up a bit towards the end. Someone I was with suggested adding a 1kg weight on each cylinder. I’ve read a lot of animosity on here towards this, but I’m not clear why the hate. You’ll be wearing the weight anyway. May actually help with trim a bit, no?

I guess I could see if you were doing really squeezey stuff and they could maybe get snagged, but for anything else, what’s the downside?
 
The tanks are already pretty much the heaviest tanks out there and you make it even worse.
It snags on everything it can.
It makes it harder to move the tanks forward.

And all that while bringing no benefits, yeah I can understand why we recommend against them.
 
basically what he said. AL80's are already terrible in terms of weight:gas so you just made it worse to deal with on the surface
Most sidemount divers are foot heavy anyway so the AL80's make it easier to dive
AL80's are a lot easier to deal with in the water than steel and you just ruined that by making them that much heavier.

If you got foot light, are you sure you weren't slightly underweighted or that you didn't have things like harness weights up on your shoulders for steels?
 
i have never used weight on the tanks but quite frankly i see it as no big deal. i understand why in some situations it could be a problem. but if ow diving, it is fine in my opinion, even if it is not necessary. if travelling and not using the usual dedicated rig, some people like to carry a couple of tank straps to attach the lower tank clip. so some like to add extra weight while they are at it. for them it provides a quick and easy option to add some lead and it means they don't have to worry about moving the lower clip to the front dring. some divers like to do it this way. no biggie.
if you are boat diving, you (or someone else) would be loading tanks on the boat first and then adding the hardware anyway so it won't make a difference when carrying on land.
there are some divers that are naturally feet light. me, i am feet heavy in my drysuit but feet light in my 1mm wet suit. go figure. so even though i personally have not used weight on the allum tanks, this solution may be an easy way to trim out for some as it may be difficult to add weight low on the harness.
do what you are comfortable with as long as it is not a major hazard for you or anyone you are diving with.
 
The historical context to this is that back when 'mainstream' agencies first introduced sidemount courses (circa 2012), an awful lot of instructors fast-tracked to sidemount qualification on very short, insubstantial, courses.

At that time, there were very few resources on sidemount diving, and nearly all of those concerned 'Florida-style' rigs using steel tanks. Many of those instructors and I.T.s had to self-educate (make it up as they went along) and tried to replicate what they saw online.

To make matters worse, Hollis pretty much dominated the sidemount BCD market at that time - the SMS50 was selling in droves as a 'warm-water, recreational' solution. As many should appreciate, that BCD is entirely unsuitable for aluminium tank diving - with butt-rails, thick independent bungees, no spine adjustment, no front-waist D-rings etc..

The Razor BCD was available at that time, but the need for time and expertise in configuring and adjusting it intimidated and deterred many warm-water sidemount instructors from adopting it.

In contrast, the SMS50 etc offered a quick-adjust harness, which pandered to the comfort zone of many recreational instructors. It was 'easy'.

Obviously, that situation was fine for those instructors actually using steel tanks, but a great many of them were diving in warm-water locations where AL80s are ubiquitous.

Those warm-water 'sidemount instructors' unsurprisingly couldn't replicate good results using steel-cylinder principles with aluminium tanks. As you might assume, the results were spectacularly bad.

The only recourse for that initial wave of zero-to-hero warm water sidemount instructors was to start slapping lead weights onto aluminium cylinders. A messy, inefficient short-cut to compensate for a lack of understanding and non-existent expertise.

Thankfully, that situation is pretty much over nowadays - the instructor community has had the time and ample resources to effect more appropriate solutions... and there's a much wider range of appropriate warm-water BCDs available.

As a consequence, the use of lead weights on aluminium tanks became synonymous with bad sidemount instruction. That's in addition to the actual performance and operational drawbacks to the issue.

What shouldn't be judged, or assumed as bad, is where cold-water/steel-cylinder divers using 'Florida-style' rigs opt for that same solution as a quick-fix when briefly travelling on vacation.

I think we can all understand why that's done - there's a reluctance to buy a second sidemount rig specifically for using aluminium cylinders only for a week or two each year on holiday.

That said, there are better solutions nowadays. Rigs like the XDeep Stealth transition easily and appropriately between steel and aluminium cylinders... and/or you can purchase very economical light-weight, warm-water/aluminium suitable rigs like the Deco Sidemount for vacation diving (the cost of that rig would be offset just by avoiding potential excess baggage costs from hauling a heavyweight 'Florida' rig on a couple of vacation flights).
 
/...To make matters worse, Hollis pretty much dominated the sidemount BCD market at that time - the SMS50 was selling in droves as a 'warm-water, recreational' solution. As many should appreciate, that BCD is entirely unsuitable for aluminium tank diving - with butt-rails, thick independent bungees, no spine adjustment, no front-waist D-rings etc..

The Razor BCD was available at that time, but the need for time and expertise in configuring and adjusting it intimidated and deterred many warm-water sidemount instructors from adopting it.

In contrast, the SMS50 etc offered a quick-adjust harness, which pandered to the comfort zone of many recreational instructors. It was 'easy'..../

That's true enough if the diver left it stock.

However it was (and still is) easy to rig an SMS 50 for a continuous loop bungee or a pair of loop bungees. And while it has a tail plate with rails, it's a small tail plate that can be ignored. There is indeed no spine length adjustment, but unless you are excessively tall, the shoulder straps can be adjusted to put the waist strap where you need it. and you can obviously add another set of D rings on the waist strap or use sliding D-rings to keep aluminum tank tails from floating up once the tank pressure gets under about 2000 psi.

The fact is the SMS 50 was incredibly easy for divers to trim out in, with a variety of tanks, including aluminum tanks, if the diver or instructor knew what he or she was doing. In other words the SMS 50 got a bad reputation due to poor instructors, not because it was an inherently bad design.

That said, it had a very limited application given the Florida style tail plate, which was great for steel tanks, but with just 25 pounds of lift, it was really limited it to small steel tanks, or aluminum tanks where the tail plate wasn't really used.
 
That's true enough if the diver left it stock.

However it was (and still is) easy to rig an SMS 50 for a continuous loop bungee or a pair of loop bungees. And while it has a tail plate with rails, it's a small tail plate that can be ignored. There is indeed no spine length adjustment, but unless you are excessively tall, the shoulder straps can be adjusted to put the waist strap where you need it. and you can obviously add another set of D rings on the waist strap or use sliding D-rings to keep aluminum tank tails from floating up once the tank pressure gets under about 2000 psi.

The fact is the SMS 50 was incredibly easy for divers to trim out in, with a variety of tanks, including aluminum tanks, if the diver or instructor knew what he or she was doing. In other words the SMS 50 got a bad reputation due to poor instructors, not because it was an inherently bad design.

That said, it had a very limited application given the Florida style tail plate, which was great for steel tanks, but with just 25 pounds of lift, it was really limited it to small steel tanks, or aluminum tanks where the tail plate wasn't really used.
Agree except for the bungie part - the native Hollis bungie setups (until recently) have been awful.

Then again, I often put 2lbs of lead on my sidemounted CCR bailouts. But those are OW bailouts and with any helium in them at all the butts are super light - even in freshwater. Using a butt plate on a backmounted CCR is really the ideal way to mount these and in order to keep the butts down you need the lead - which in this application doesn't really snag anything more than the cam band or anything else on a CCR.
 
Instead of starting a new thread to get bashed in I’ll just bump this necro-thread and take my lashings here. 1/8” x 4” lead bands on my ow dilout LP50s.

IMG_7449.jpeg
 
Instead of starting a new thread to get bashed in I’ll just bump this necro-thread and take my lashings here. 1/8” x 4” lead bands on my ow dilout LP50s.

View attachment 815617
Why? Those tanks are already negative. Now when you take them off you will be buoyant.
 
I need the weight, and I’m not taking them off. Also allows me to dive them without any changes to my rig, I dive hp100s when OC
 
https://www.shearwater.com/products/perdix-ai/

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