ALU 80's weighted for sidemount?

[AcDriver]

Hi,

New sidemounter question. I have been told to attach 4lb weights to the cam bands of my alu 80's to keep them from getting floaty at the end of the dive. I don't see this being done in any of the photos I see online.

Is this common and a good place to start for proper trim? I am diving dry in COLD water (heavy undergarments) if that is a factor in the discussion.

Thanks,

AC

[DA Aquamaster]

One of the local side mount divers/cave divers here uses 2 pound weights cam banded to AL80 stage bottles as he (like myself) was never able to get the Edd Sorenson approach to top clipping stages with a bungee to work to the degree desoired in keeeping the tail down on a more or less empty stage.

In my opinion, 4 pounds of lead on an AL 80 is overkill and would neutralize an empty AL 80 without a reg. When you consider the reg and the remaining 3rd of gas (if you dive stages that way) then 2 pounds of weight is enough to keep it from floating during most of the dive.

For the primary sidemount tanks, I think it makes a lot more sense to just re-clip them to waist D-rings when they get down to 1500 psi or so and start to get floaty.

[phillip1]

definitely not a good place to add weight, I tried it a while ago and really do not like it. When the tanks get floaty at the end of the dive clip them from your buttplate or hip drings to the front waist drings, this will help keep the butts down.
Whatever weight you need add it to your harness and not the tanks.
a video i did shows this concept below.

http://www.youtube.com/watch?v=0TBTbh3ehA0

[Slüdge]

to work to the degree desoired in keeeping the tail down

Who are you, Curly from The Three Stooges?

[sskasser]

I dive with the weight on my body, not on the tank, and rig the tank accordingly to keep it off the ceiling.

[RN]

What you're seeing in the Internet videos is divers who reclip their cylinders. There are some systems that have several waist d-rings that are used, as the cylinder gets lighter, to keep the cylinder trim. This method doesn't work very well. Even one of the big proponents of this has/had a video up that showed his cylinders out of trim because it was the end of the dive. Although, in the video, this occurs at the beginning. My rig has 2 waist d-rings that are positioned midaxillary and used for deco cylinders. I prefer not to place more d-rings along the waist, so I use 3lb weights on my 80s and they work well to keep the cylinders where I want them throughout the dive. Because you are wearing heavy undergarments, you are going to need additional weight on your body to counteract that. I wouldn't not use it on the cylinders, though. I'd add it to the harness or to a weight belt.

[DA Aquamaster]

Who are you, Curly from The Three Stooges?Russell, you know my name is Larry, so I can't also be Curly.

[AcDriver]

Thanks to all for the info. Keep it coming if others have thoughts please.

Here's one of the sources that says to put weights on the tanks. Scroll way down to the part about rigging the tanks.

http://www.advanceddivermagazine.com/armadillo.html

AC

[Burke]

That's disappointing to hear... I dove with a side mount diver a couple months ago and took note of how he had extra D-rings to trim out the tanks. I considered trying that for stage bottles. I usually end up having to lever the stage down to go thru a restriction like the Lips, hand on the valve and elbow pushing down on the tank. The extra D-ring seemed like an elegant solution...

[stairman]

Are you sure the photos your looking at are aluminum 80's and not steel 100's or 85's where buancy of tanks isnt a problem? They are nearly identicle in size.

[AcDriver]

Are you sure the photos your looking at are aluminum 80's and not steel 100's or 85's where buancy of tanks isnt a problem? They are nearly identicle in size.

Hi, If you asking me about which tanks are which. Here is the text from the Advance diver mag armadillo site.

"Proper set-up of the side mount cylinders is essential to maintain proper buoyancy and streamlining.

The cam strap is slipped over the cylinder and tightened by pulling the strap tight and closing the cam buckle. The distance from the top of the cylinder valve the cam strap is placed varies depending on your chest length. A good rule of thumb is to measure from your armpit to your belt line. Place the cam strap the same distance from the top of the valve.

Some types of cylinders, such as aluminum tanks, become buoyant as they are emptied. For these cylinders, you may need to attach hard weights to the cylinder cam straps in order to compensate for the buoyancy change. Hard weights can also be added to the cylinder cam straps to offset the buoyancy of wetsuits and dry suits. If additional weight is needed due to dry suit buoyancy, a standard weight belt can be used under the Armadillo harness."

[NEON]

This method doesn't work very well.

Why not?

It does work very well for me!

I would not bother with cam bands either - a SS hose clamp not only costs less but also seems more streamlined and reliable.

As far as the video goes, could you please post a link?

[RN]

Why not?

It does work very well for me!

I would not bother with cam bands either - a SS hose clamp not only costs less but also seems more streamlined and reliable.

As far as the video goes, could you please post a link?

You can see in the very beginning of this video how poorly trimmed the cylinders are - http://www.youtube.com/watch?v=yDp58Wrz4Uk&feature=fvw

In a discussion with him, he told me that was footage from the end of a dive and the cylinders were low thus out of trim.

[NEON]

I think this could be mitigated by lowering the profile and changing the position of the front d-rings and or by reducing the length of the line holding the boltsnap. It has worked very well in my experience.

[Webmaster]

When I did that I put weight on the tank and on myself.

I would suggest using a separate hose clamp for the weight, that way you can adjust the weight where you want it on the tank without altering your attachment point.

[DA Aquamaster]

There is not going to be a single "right" answer and there will be no consensus on the subject. Some divers tend to state their cases in very black and white/authoratative terms but it does not neccesarily make it any more valid. In truth what works works and what works for one diver may not be exactly the same as what works for another diver.

The OP mentioned cold water and I have a few thoughts on weighting tanks versus the diver based on both warm and cold water experience. If using steel tanks (LP95s, X7-100s, LP 85s etc) the majority of the weight will come from the tanks in cold water with perhaps some additional weight needed to offset the suit buoyancy when the tanks are close to empty. For example, depending on my drysuit undergarments this ranges from 4 to 10 pounds of extra weight.

One of the things you'll need to practice is moving and emoving one or both tanks under water. With a dry suit and heavy undergarments, you'll find the need to dump the wing, fully vent the suit and then you may still find you are positively buoyant with both tanks removed or even with just one removed if you are fairly low on gas in each tank. That strongly argues for the need to add any extra weight to you rather than to your primary sidemount cylinders as that will only aggravate the trim and buoyancy issues that occur when one or both tanks are removed or swung forward.

In contrast in warm water it is likely that all the weight comes from the tanks if steel tanks are used. However, the odds are also good many divers are neutral to perhaps even a bit over weighted toward the end of the dive even without the tanks - in particular if trim weights are used near the shoulders. That basically means it is a moot issue whether trim weights are added to the tanks or not as it won't have any real effect on the diver if the diver has to move or remove a tank. As long as the wing will support all the weight at the beginning of the dive it does not matter all that much. But again, a cold water diver may not have that luxury.

If you combine warm water with AL 80s then again it's a situation where weight on the tanks makes sense and may have little or no downside.

Stages are a slightly different issue as you need to be configured to be able to drop them anyway, so again, trimming a stage with weight can work as long as the total weight of primary, stage and deco gas at the start of the dive can be supported by the wing.

Personally, I'd take what ever anyone says with a grain of salt and filter it through the lens of what you need to accomplish in your diving and also temper it with a solid understanding of the competing interests that must be balanced. It's the presence of different and sometimes conflicting needs and goals that ensures multiple divers will have multiple opinions on what is "ideal" in terms of sidemount configuration.

------

If you are going to add weight to a stage I agree it makes sense to use a separate attachment point. Less weight is probably always better and if you are trying to hold the tail down on an AL 80 take advantage of the longer moment arm you get if you attach the weight as close to the bottom of the tank as possible.

Also, I think there is some advantage to having it be easily removable so it makes sense from that perspective to use a low profile cam band rather than a hose clamp.

[AcDriver]

Everyone, thanks for your input. Keep it coming if there's more!

DA, special thanks for taking the time for such a complete response. Good input!

Based on all the input I have decided to proceed as follows. I am planning a shore dive tomorrow with my new sidemount gear. (Nomad XT, alu 80's and drysuit) I plan on walking in a "bag-o-weights" to use. I will leave the tanks unweighted but have installed weight pockets I had lying around, one on each tank cam band. (if this works I will move a lighter weight south on the tank on a seperate attach point) The nomad has the optional weight pack for the center of the wing. I will install two pound weights on each shoulder harness.

Then with the help of my buddy we will start adding weights till we can get the trim dialed in. Trying to avoid the weight on the tanks, and if needed only a couple of pounds on them.

I wish we had a sidemount mentor up here, but most of the sidemounters are smarter then us and live south where there is not 11 months of winter!

[AcDriver]

You can see in the very beginning of this video how poorly trimmed the cylinders are - http://www.youtube.com/watch?v=yDp58Wrz4Uk&feature=fvw

In a discussion with him, he told me that was footage from the end of a dive and the cylinders were low thus out of trim.

It's hard to tell from the video as the photographer is staying in position relative to Steve.....but it appears that he is descending...i get the impression that he is doing it at pretty good clip...and I wonder if the vertical flow isn't contributing to the tank lifting.. Pure conjecture on my part!

[RN]

Not at all. I discussed this video with Steve and he admitted the cylinders are out of trim because it's the end of that dive.

[alias]

Then with the help of my buddy we will start adding weights till we can get the trim dialed in. Trying to avoid the weight on the tanks, and if needed only a couple of pounds on them.

I wish we had a sidemount mentor up here, but most of the sidemounters are smarter then us and live south where there is not 11 months of winter!

Where do people from Elmira, NY dive?? ;)
Seems to be still good 3 hrs from us and certainly can't offer any mentoring but if there is any diving (!) we have been trying to get our SM rigs in order for the last year and slowly getting there. I would have to say though that hats off to you if you get Al tanks working with cold water rig. I would look for steel right away. I find them that much of a pain with the extra weight requirement.
I was first very much against putting any lead on tanks but with Al:s I find that some pretty much has to go on tanks - there just isn't enough room elsewhere - and I get so uncomfortably arse-up trimmed because there is no other location that is just right. This becomes very obvious problem when diving SM in OW and sucking tanks way emptier than in cave...

[JamieZ]

Where do people from Elmira, NY dive?? ;)
Seems to be still good 3 hrs from us and certainly can't offer any mentoring but if there is any diving (!) we have been trying to get our SM rigs in order for the last year and slowly getting there. I would have to say though that hats off to you if you get Al tanks working with cold water rig. I would look for steel right away. I find them that much of a pain with the extra weight requirement.
I was first very much against putting any lead on tanks but with Al:s I find that some pretty much has to go on tanks - there just isn't enough room elsewhere - and I get so uncomfortably arse-up trimmed because there is no other location that is just right. This becomes very obvious problem when diving SM in OW and sucking tanks way emptier than in cave...

Seneca Lake has some diving in it, which the poster is close to. Some old wooden barges and ugly fish but it is diving :) Where in NY are you located?

[rchrds]

I have to agree with Rob- weight on the tank is by far the most convenient, but some factors must be considered- Only enough weight to control the tank buoyancy should be on the tank. If you need weight to keep your drysuit/wetsuit and your body neutral, that weight should be on your body. You should be able to remove your tanks and still be relatively neutral in the water. Once you have that figured out, a 3 or 4 lb weight (depending on the brand/year of AL80) will keep the tank under control. Yes, you can clip and reclip the tanks. If you are in big cave, or are less damage conscious. The tanks just don't float level this way, regardless of how simple it looks. See the video.

But the WORST suggestion posted here is to rely on that remaining third to keep the tank bouyancy under control. You must be completely under control when you are operating in an emergency on that last 1/3. If you are fighting trim, along with anxiety from being in your last 1/3, you will gobble gas even faster, compounding your issues, and sliding faster towards your expiration.

Of course, weight on your stage bottles is unnecessary, but someone brought that up.

Jason

[Squirrel Girl]

But the WORST suggestion posted here is to rely on that remaining third to keep the tank bouyancy under control. You must be completely under control when you are operating in an emergency on that last 1/3. If you are fighting trim, along with anxiety from being in your last 1/3, you will gobble gas even faster, compounding your issues, and sliding faster towards your expiration.

Totally agree with Jason on this point. I prefer to be a little heavy (diving weight-wise) so that if I'm on my last 1/3, which has happened, fortunately rarely, I'm not fighting it when I want to be fighting it least.

[DA Aquamaster]

It's not glamorous, but it's no different than OW - to be properly weighted you need to be able to be neutral with minmum gas remaining. I'm surprised the issue is even in question, yes, we all dive with at least a third in reserve, but we also need to be sure we can actually use that third effectively and efficiently.

[Diverlee]

I just returned from a trip where I used AL80's. For me I clipped 3# on each cam band and also had to add 2# on each shoulder. I was diving wet in a 5mm. This worked for me. I tried everything in the pool first.

[AcDriver]

Where do people from Elmira, NY dive?? ;)


Seneca Lake has some diving in it, which the poster is close to. Some old wooden barges and ugly fish but it is diving :)

JamieZ nailed it. Seneca Lake. Deep (over 600 feet) cold and dark, with old barges, brown ugly fish and millions of zebra mussles. We call it home. :smt022 But at least it's wet!

[phillip1]

I think this boils down to what you feel comfortable with, both methods work, I think that all things being equal it is always better to have your weight on your harness and not the tanks, it is more efficient and much easier that way.

Also if you put the weight on the tanks it will be the same problem in reverse really and the tanks will be butt heavy at the start of the dive anyway.

I have tried diving with weights on the tanks, and dove that way for a while and really did not like how the tanks felt especially when unclipping tanks for tight stuff, it throws your buoyancy off a bit to not have ballast on your harness (yeah, yeah I know in stuff that tight it does not matter, but really it does) and just makes the tank feel heavy.

I then tried the clipping method which I find simpler and way better for trim and have stuck with that since then.
It takes a fair amount of messing around with the harness, dring positions etc.. to get it right but once you fine tune your rig it is IMHO a much better solution than adding weights to the tanks for nothing else but to keep the butts down.

It does take a lot more fine tuning and practice to get it right with the clipping method but it works perfectly once you get used to it.

Done right the butts may ride slightly up when the tanks are empty but only slightly out of horizontal though.

However the only thing that matters is what you feel works best for you and the way you dive, try it out for yourself, I may be totally wrong and putting weights on the tanks is better, hey I even used to BM lol...

[alias]

Seneca Lake has some diving in it, which the poster is close to. Some old wooden barges and ugly fish but it is diving :) Where in NY are you located?

I am in Saratoga County. Never dove in Seneca. Might have to check it next summer.

And I agree about requirements being same for OW and overhead. In my case OW dives were the ones were it became OBVIOUS that I do not want to be weighted correctly (by amount) but have the weight in wrong place IF I end up sucking the tanks down. It's not only the amount but placement that was my point. One can live with some sort of illusion that it's tolerable to fight the trim if one regularly leaves water with 40% gas left on cave fills. In OW I might make two dives out of same set, and it gives you good idea how different tanks fly when you finish at 700 PSI, and respect how difficult you don't want them to fly if you ended up at 200.

[RN]

Also if you put the weight on the tanks it will be the same problem in reverse really and the tanks will be butt heavy at the start of the dive anyway.

Not if you have the cylinders set up properly.

[Meister481]

One of my favorite dive was in OW sidemount with Al 80's, a 3 mm shorty and lots to look at. Trim wasn't an issue because I put a couple 2's on the harness belt and clipped the cylinders off to the D rings. Used standard backmount stages.

[NEON]

Not if you have the cylinders set up properly.

If this was true why do so many sidemount divers with weighted tanks also put weights above their chest d-rings or on their shoulders?

[DA Aquamaster]

I agree with Rob that buoyancy shift due to breathing down the tanks suggests the tanks are not properly rigged. I found I had to move the lower attach point up or down slightly as needed to find the sweet spot to minimize/eliminate any shift as the tanks were breathed down during the dive.

On the other hand, I find it helps to have trim weights on the shoulders of my Nomad to eliminate the need to arch my back to maintain hirizontal trim. I can do it without the weights, it just takes some effort and effort equals more O2 burned and more CO2 produced. My opinion is that it is an artifact of wing and where the gas rides in the wing. You can tighten the bungee and bias it toward the top of the wing, but there are limits.

That said, there are those that feel trim weights on the shoulders are heresy, so your mileage may vary, but i don;t think weighting the tanks to keep the trails down has anything correlation to the need for trim weights. a diver may have co-occurirng problems but in my opinion, they need to be resolved separately, and consitent with that, I am not a fan of weighting your primary sidemount tanks.

[Slüdge]

buoyancy shift due to breathing down the tanks

I think it has been established that Phillip has some magic tanks where this doesn't occur.:smt102

[DA Aquamaster]

Is it like a magic stew pot that never gets empty, or is it like a magic stew pot that never has buoyancy shifts?

[phillip1]

I never said I had magic tanks that's ridiculous, I have a magic wetsuit.
No matter what you do the tanks will shift when empty, that said with practice and fine tuning you can really minimize the problem to an non issue, by clipping the tanks to the forward Drings at the right pressure.
Obviously the tanks do become more buoyant at the end of the dive but clipping them at the right moment and keeping them clipped forward will keep the butts down to almost horizontal.
You should be able to tell more or less how much air (within 20-30 bars) you have just by how the tanks ride, and know when to clip them forward, this takes practice to get right but like anything else practice makes perfect.
Of the two options; weight on the tanks or the above IMHO I have found that the clipping forward solution is the best, not the easiest at first but the best and most efficient for me at least.
Adding weight to solve a problem that does not need weight is kind of adding extra "stuff" were it really should not be.

[CaveBuddy95]

+1 Phillip
Weights on the tanks are, as it been said already not the best option. If needed it must be placed on the body.
As for forward D-ring option, I've been using a slightly modified version, bungee d-rings.
It's easy to 'slide' them forward as the tanks are getting empty. Like this I don't need to unclip, just push the tanks or d-ring forward.

No black magic here, just Sidemount diving.

:)

[RN]

If this was true why do so many sidemount divers with weighted tanks also put weights above their chest d-rings or on their shoulders?

This has more to do with the position of the cylinders and trim of the body. Because cylinders mounted on the side are positioned closer to the feet than when backmounted, this shifts the center of gravity somewhat. In order to offset the positive buoyancy created by your lungs, you need some weight in the area of your lungs. With backmount, this is accomplished with the valves and manifold. With sidemount, it's accomplished with trim weights.



Obviously the tanks do become more buoyant at the end of the dive but clipping them at the right moment and keeping them clipped forward will keep the butts down to almost horizontal.

So you're saying Steve isn't doing it properly in the video I linked?

[NEON]

I disagree! Neither Steve, nor any of the SM divers I have dived with utilizes trim weights and they are all horizontal in the water. As far as Steve "not doing it properly" - this is open water after all and trimming the tanks at the safety / deco stop is not critical IMHO.

Also, it is not fair to jump to conclusions based on one of the earliest videos of the Razor when things were still being dialed in, etc.

As I mentioned in a previous post the issue is easily addressed by moving the front waist d-rings forward.

[phillip1]

This has more to do with the position of the cylinders and trim of the body. Because cylinders mounted on the side are positioned closer to the feet than when backmounted, this shifts the center of gravity somewhat. In order to offset the positive buoyancy created by your lungs, you need some weight in the area of your lungs. With backmount, this is accomplished with the valves and manifold. With sidemount, it's accomplished with trim weights.




So you're saying Steve isn't doing it properly in the video I linked?

It looks like Steve is doing exactly that and the beginning of the video is the end of the actual dive at the the safety stop at the end of the dive with tanks presumably empty, they are clipped forward.

I just think that adding weights to tanks for the sole purpose of keeping the butts down is complicating a situation that has a very simple easy solution, clip the tanks forward at the right pressure. Having said that I have seen very experienced SM divers who prefer having the weights on the tanks and that also works just as well as the clipping thing so it really boils down to what a particular diver prefers, I just find that having to add a tank band with weights is a bit more complicated, plus I personally did not like how the whole thing felt when I unclipped tanks for tighter passages.

As for trim weights they are not needed at all if you set up your harness and tanks correctly, SM takes a lot more messing around than BM as it is an infinitely more customizable system no matter what harness you use, it is not a one size fits all thing like BM were the only real difference is how much weight or what size wing you use.
BM is more of a standard one system fits all type thing, sure you can customize little details like were to put backup lights and an extra knife but that's pretty much it.

On the other hand a SM harness is a infinitely customizable system, that you can modify to suit your individual diving needs, you have so many options as to how to setup a SM rig that it takes time and many dives to find what works best for you, even how and were to attach tanks is a whole new world of options, not to mention were to put weights and how to setup the regs or what color fins to use.

After spending the time and testing out all the different setups and techniques available you will one day be one with your harness, everything will be in perfect balance and you will wonder why you did not switch to SM earlier.

[RN]

Phillip, to clarify your statements, specifically, As for trim weights they are not needed at all if you set up your harness and tanks correctly, you are only speaking of aluminum cylinders, correct. I believe you've stated several times you have no experience in steel cylinders. That being said, trim weights are necessary with steel cylinders. I was against trim weights for a long time until I did some dives in a wet suit and couldn't get horizontal without them. Most of my students are also diving wet and we end up using anywhere from 4lbs to 10lbs in trim weights around the shoulders. I've set a lot of people up in sidemount and there is no way to set up a harness and cylinders on some people so they are horizontal without trim weights. If you know a better way, I'll gladly take the advice and incorporate it. But remember, I'm referring to sidemount with steel cylinders, not aluminum.
'

[DA Aquamaster]

I agree.

You can fake it in terms of arching your back to maintain trim without them, but that adds up to a lot of effort over the course of a dive. In a wet suit, with steel tanks if you are relaxed and motionless, the odds really, really, good you will trim feet low without trim weights. It's a function of the center of gravity being aft and the center of buoyancy being forward, and trim weights on the shoulders help a lot to correct that.

Ideally, you'd have a wing that places the bulk of the air aft with nothing above the bottom of your shoulder blades. But that then means the air cell has to be either wide across your lower back and hips, bulky/high profile over your lower back, or it will have limited lift and may not be suitable for two steel tanks, let alone the addition of one or two stages and a deco bottle. So, if you are diving steel tanks and a wet suit and need adequate lift, you are going to have to make a compromise somewhere - and I'd prefer trim weights on the shoulders to a high profile bladder or a bladder that is too wide to easily reach around.

Personally, with a 3mm wet suit and hooded vest, I need 6 pounds on the shoulders with steel 95s.

[phillip1]

Phillip, to clarify your statements, specifically, As for trim weights they are not needed at all if you set up your harness and tanks correctly, you are only speaking of aluminum cylinders, correct. I believe you've stated several times you have no experience in steel cylinders. That being said, trim weights are necessary with steel cylinders. I was against trim weights for a long time until I did some dives in a wet suit and couldn't get horizontal without them. Most of my students are also diving wet and we end up using anywhere from 4lbs to 10lbs in trim weights around the shoulders. I've set a lot of people up in sidemount and there is no way to set up a harness and cylinders on some people so they are horizontal without trim weights. If you know a better way, I'll gladly take the advice and incorporate it. But remember, I'm referring to sidemount with steel cylinders, not aluminum.
'

Yes I was referring to AL tanks ( I should have specified), I have zero experience with steel tanks and steels would not really be a good choice for the caves here, the conditions here are very similar to Mexico.
Having said that if you need to add weights anyway to dive, and the weight are totally necessary to maintain trim by all means use trim weights.
However no matter what harness you use there is a way (IMHO) to set it up to not require trim weights, I tried steels once a year or so ago at El Dudu and although I ended up being a bit too negative the trim was still good.
Another thing I noticed is that if you use heavy negatively buoyant fins like jetfins or XS scuba classic fins etc, it will affect trim big time and will throw the whole setup off and make the diver feet heavy.

I think that SM takes a lot more time and effort to get it right, it is not a thing you can just set someone up in and off they go in good trim, I think in BM there is much less "balance" and fine tuning involved so to speak but BM is not really customizable, it's a one system fits all thing.

People will need to test all different ways to set up SM rigs and find what works for them and the diving they do, maybe some people really need trim weights and that is what works for them, there is nothing wrong with that and 99.9% of divers need weight anyway.

SM is a much more "involved" setup, as in you need to try many many different ways to do things before finding the right combination for you.
It took me a long time to get it right, I tried a lot of different setups and did many many dives in many different setups before finding what worked for me, as opposed to BM were it was very minimal adjustments and the trim was good and I thought it was comfortable and fun.

However I never even came close to being as comfortable BM as I am now in SM and I enjoy diving so much more SM, it is just way more fun SM period.
It is well worth the time and effort.
Unless you actually try SM and put in the effort needed to get it right it is hard for someone to understand how much better it is.

[cwswine]

I’m a new open water SM diver and do so because of physical limitations on the carrying weight of doubles. The reason I want to dive doubles I want to do some deeper wreck diving with maybe a Padi Tec 40 or 45 Certs. This is one the few forums that has good info on sidemount and read it daily. That said this is what I have found diving SM with steel tanks.


Dive Rite EXP with two LP85s and 7Mil wetsuit required 6lbs on the shoulders but was able to reduce that to 4lbs moving the tanks band forward. I felt over weighted and very unconformable, will limit steel tanks and SM diving to drysuit only. Never tried the EXP in drysuit. I was not impressed with the EXP.


Oxycheq Recon with two LP85s, drysuit, Hollis F1 fins with the bands set at 17 inches down from the top tank value. I was still slightly over weight but my trim was good and didn’t have to add any weight any where. With the Recon I had a side to side trim was terrible and never did figure out what the problem was but I’m sure it was something I was doing wrong.


Hollis SMS100D with two LP85s/HP100, drysuit, Hollis F1 with bands set at 16 inches from the top of tank value. Wow - no weight/not trim weights and best trim yet. Hollis seems a lot more stable in the water and by far the best of three in my opinion.

I have about 40 or 50 SM dives of less than 10 minutes each just trying to get things sorted out but I have had a lot of fun doing it. Yes, I’m schedule for SM class to break all the bad habits I have already learned on my own.

[AcDriver]

Thanks everyone for all your comments and suggestions! TBH when I first posted this question I was a little concerned I was going to get slammed for posting a question with "such an obvious answer." (my quotes). It's fun to see that SM is still an evolving art and that there is room to grow and try new things.

I wasn't able to get into Seneca lake on Saturday. 1 foot waves with whitecaps and 20 plus knot winds. Seemed a stupid place to try SM out for the first time. Sunday we were able to get some time in the local pool. I went with two pounds of trim weight on each shoulder. 10 pounds of weight in the Nomad weight pack option. Wearing my full cold water undergarments...can you say heat stroke. No weight on the bottles. It was close...but I was still a bit light....and trimmed a bit nose down. I added 4 pounds to the lower portion of the weight pack. Total weight dead-on with full bottles....may need a tab bit more as the bottles empty. But a great starting place. Bottles were not trimmed, nor were they needed to be. I am sure a SM instructor would have spit his regulator out in disgust. BUT! The stability of this system is amazing! I felt rock stable and depth was easily controlled with breath control. I bit of gas in the arms brought my nose up. FANTASTIC! I see the light!!!!

I will be diving all weekend at Dutch Springs trying to dial this in some more. I think I will try to move the 4 pounds to the tanks and see if that brings the tanks down and under my arms a bit more and brings my nose up a bit. I am also going to mess around with the lower tank attach to see what effect that has on their trim postion.

I hestitate to get into the technical merits of weight on the tanks or only on the "belts" because frankly I don't feel qualified at this point to make any arguements....with my limited SM experience. But here is something for the experts to debate if they wish. One of the arguements is that I soundn't put weight on the bottles in case I have to ditch or leave them. My question is, why would I ever do that? (I am talking OW here, not cave. Something I know even less about then SM) The tanks are part of my "System". I wouldn't hand off my tank to someone in an air-sharing situation. Just my long hose. If you're in a BM config you don't hand off a tank...just the gas. My plan with my dive partners is the same. SO, if I am not breaking down my "system" I will always have the tank, and thus, always have the weight. So if putting the weight on the AL80's helps to control their floaty-ness, and I need the weight to sink my undergarments, why not put it on the tanks? <I am now donning my flame-retardent flight suit>

Besides when I am supermanning the tanks and swimming Steve B.-like-an-eel through the wrecks it will keep the tanks neutral for more of the time. :roll:(I am not holding my breath that I will be eel-like for some time in a SM config.)

[AcDriver]

Did five dives at Dutch Springs this weekend. Ended up with two-two pounders on the sholder d'rings. 10 pounds on the nomad weight pack and three pounds on the cam strap on the tanks. It was amazingly stable. One of the BM GUE instructors said he had heard from some of his divers that "I looked really good" in the water. A complement from this instructor is the highest form of praise I know. Again, I think a SM instructor would have cried in disgust....but I felt really comfortable. I didn't superman the tanks so I have no idea what effect that will have. But I love the way I can move underwater in this configuration. And the bottles seem to behave very nicely thoughout the dive with the weights on them. They were down to about 300 pounds each at the end and I wasn't fighting them to keep them down. And with my thick undergarments I had enough weight to keep just enough air in the suit to keep me stable and warm. Perfect!

AC