Side mounting AL80's how do you trim your tanks?

I did mine the same as I do my 85's. just added 2 lb wts on each one. I also had 2 lbs on each side on my shoulder straps. This was for wetsuit diving.

 

I like sliding D-rings on the waistband. As the cylinder bottoms get floaty, just slide the rings forward down. I took "rigid" D-rings (the ones where the ring is mounted on a plate) and slightly bent the plate. This allows to slide the rings forward or backward on the waistband exactly as much as needed.

---------- Post added September 14th, 2013 at 01:01 AM ----------

P.S. Just discovered that two posts back MSergeant has ilustrated it in his video.

 

A see-saw is a pretty good example, if you put a heavy object at one end the rear will rise quicker than if you but a lighter object at the same point, it's exactly the same principle for adjusting balance and trim by body positioning.

Regarding the tank lift I'll trust your figures, either way there should be no beach ball for 9lbs of lift? Remember most of use have around 6 litres of lung capacity we can use for additional lift - I can assure you anyone with the beach ball problems with the Razor 2 when using Al80 is over weighted - and that's based on both simple math and a lot of time in the water putting the theory into practice ;-)

 

So her it goes guys, i have made some edits to my rig and thought i would share them, i made them about a month ago and have given it 30-40 dive's and am happy i have added (as suggested ) some d-rings on my harness at the waist, frontish , and now i have two clips on the cam bands on the tank and i clip both one on the but plate and the other on the waist the tanks don't move even when i swim on m back or any other position, i am even considering trying to take the 700gms of the tank and seeing soon, but i guess we will always play with our gear and try and find a better and better way to have it all sit thanks for the feed back and stuff

 

I'm thinking about trying sidemount - and do have an instructor for it, but not for a while. This 2 clip idea seems an excellent solution to the neg to positive tail swing of an AL cylinder. Only downside I see is there are now 2 clips to work rather than one. What else am I missing?

FYI, most of my SM will be with steels (cold water drysuit diver), but my current application is to sidemount (rather than sling) an extra bottle onto my BP/W backmount for extended range diving. Worked sweet the time I tried it except for the AL cylinder trim - the pictures are way too embarrassing to post. I picked an AL tank for this rather than a steel since the OVERALL buoyancy of the AL is near neutral compared to the -9# of the HP80. Since I am using the SM tank on one side only I want to stay balanced.

 

I'm gonna leave this here, just my opinions etc.

How i trim my Ali80s for sidemount diving. - YouTube

 

Watched that already and learned a lot from it and the other prior posts. Still doesn't answer my question however -- which is -- What, if any, is the down side to using both a front and a rear clip at the same time other than the obvious that you have 2 clips to work? More specifically are there any safety considerations.

Seems to me -- as a not yet SM trained diver -- that having 2 clips simplifies things especially with AL cylinders. You secure both negative, positive, and negative --> positive cylinders the same, you don't have to adjust as the buoyancy changes with gas use, and if you roll face up (which I do often) the cylinder won't shift position. Am I missing something?

Oh, and I did notice something else useful. I can stably support the cylinder at my side, while on land, even with a non-rigid (ie bungee loop) valve attachment.

 

2 clips would make a difference in an emergency or when doffing/donning cylinders in less than optimal conditions.

The real issues present when looking towards higher levels of diving; particularly technical/deco and overhead environment. Dual clips would interfere with stowage of multiple deco/stage cylinders. They would increase entanglement hazard and reduce the (intended) flexible movement of the cylinders when pushing through restrictions.

I wouldn't critique your solution in any "you're gonna die" terms - but if you are 'beginning with the end in mind"; with an aim towards advanced diving, then you would be far better served developing competency in managing cylinder trim through more traditional multi-D-ring transitions.

Also considering sidemount training - for most agencies a 'partial remove' (swing one/both tanks in front) is a requisite skill for certification. Your solution would significantly retard the operation of that skill. I, personally, judge skill performance against a criteria of 'fluidity', 'task-loading', 'retention of situational awareness', repeatable' and 'in satisfactory time'. When measured against other students with a single clip; I wonder if I'd be able to pass your performance in that skill as satisfactory (when students want to use 'alternative' configurations/options on my courses, I do allow them, but if performance is hindered/unsatisfactory, they have to change to the recommended configuration/application).

 

I don't see the second clip as a significant hindrance in ditching or donning gear, nor in swinging tank forward into Superman position. But clipping more than one tank on each side could be problematic.


Please pardon any typos. Sent from my iPhone using Tapatalk

 

DD and Kwinter thanks for the thoughtful replies. That is the kind of information I needed to make an informed decision.