question for sidemounters
If your going thru a no-mount restriction and you remove your tanks,other than holding on to them for dear life,what keeps you from becomeing too positive?Does anyone wear a weight belt for this scenario?
My death grip on the mouthpiece
I'm actually curious about the answer. Although I've never gone no mount (not sure I ever will), I kinda thought if you did, your bouyancy would probably not be that important -- if it's that tight where can you go? If you could possibly float up, I'd think you'd just turn your sidemount rig sideways (an unclip one side if need be). Once it started opening up, you could clip the cylinder back on your bungee and when you clear, you can reattach to your butt plate (same would probably apply for no mount -- but again, don't take my sceerdy cat word for it).
~Jeff
i'm no expert, but....
if the restriction is no-mount, buoyancy is not an issue, even fins can be an inconvenience. you are equally pinned betwixt floor, walls, and ceiling.
never been there though.
-skip
"Learning the techniques of others does not interfere with the discovery of techniques of one's own." B.F. Skinner, 1970.
I've used AL tanks for that kind of sidemount restriction with 1lb of weight on them and steel up til there so I didn't need any additional weight. But if I used only the AL I'd probably need to add a weightbelt for shallow (or some sort of weight - maybe a drop weight or weights on the BC/tanks).
Originally Posted by stairman
1. I have a removable neck clip that I keep in my dive rite 2 zip pocket and hook one tank to my butt ring. Or I put it down in front of me.
2. I hold the other tank out in front of me or I put it down.
3. I am weighted to be slightly negative without any tanks, so without the tanks I am perfect.
4. I dump all the air from my BC to make myself as small as possible.
5. If I am in a no mount restriction, I am pinned and bouyancy doesn't matter.
6. ALL my weight is on my Razor harness.
Hans
For no-mount i put 2 regs on one bottle( one of my bottles has H valve but normally it is plugged by ss plug). Even if i need to leave first cyl before the restriction the second steel tank is negative enough especially when full. I would use lanyard to secure it because this situation usually also means zero viz (unless you are in a very high flow clear spring) and if tank falls behind the restriction it takes the reg from your mouth with it as well (very fun to look for it). I don't care of boyancy at all until i moved forward/back to clear water. And like others said you are not going to fly up anywere (in no flow). For the high flow i would use overweighted belt. To take both tanks behind restrinction you can clip first (w/long hose) tank to your butt ring and make a sausage link formation. I never did n/m longer than for 10ft and i hated every second of doing that.
Here's what we do, as it is actually fairly common for C and I.
Big tanks- (95s-120s) You're heavy, there's no way around it. But, as Skip says, normally your are restricted top and bottom, and you're sliding the tanks along the bottom and your back along the top (usually both at the same time.) Remember to always keep one arm forward and one back, when it really gets tight, or you can get permanently stuck. All of my tanks connect with a carabiner at the aft, and are looped by the bungee at the front. The bungee is tight enough around the neck that when the back of the tank is disconnected and rotated forward, the bungee will not fall off the neck, and the tank is retained this way. Both tanks can be rotated forward and managed, but I have found that it is much easier in places that require this (Edwards, used to at Crystal Beach, Silver Glen) to take one of the tanks off completely and either carry a very small buddy bottle, or put a long hose on one bottle so you can push one ahead, and then slide back and get the other. I have found that almost always you can take one bottle off and manage to get either yourself or the tank through a smaller spot (depends on your size.) Either way, the gist of this is that bouyancy is pretty much out the window. If its silty, its going to get pretty ugly.
Small tanks- this is an entirely different story. I use aluminum tanks, so without any tanks at all, I am just a tad bouyant at the surface, wet or dry. I can control my bouyancy with breathing. Adding tanks adds at most 3 lbs (-1.5 per al40), less for smaller tanks. I can lift 3 extra lbs with my lungs, but it sucks, and makes my consumption go up. If I'm wet, I suck it up, If I'm dry, I can add a little air. The al tanks are so light that when I rotate them forward, the CG doesnt shift that much forward, and since I am controlling my bouyancy with my lungs instead of a wing, the lift CG is further forward anyway, and it is not a problem. Again, it has to be pretty tight for me to take off tanks, so most likely, I can use some part of the restriction as a pivot point, but I can still hold the tanks with my hands in front of me, if necessary (hasn't been yet.)
It goes without saying (or perhaps it doesn't) that once the tanks come off, that part of the cave is going to suffer some damage- in most cases, it'll be you and about two other folks who ever see it if the restriction is really that small, so no big deal, but if you go around taking tanks off for places that dont really need it (Potter's Delight comes to mind) and making a huge mess, you probably wont be too popular.
Another thought- add some extra cushion to your gas planning on the back side of the restriction- not only will you be thinking about that damn thing the whole rest of the dive, but you may find that you dont fit quite as well going out as you did going in- and that could cause some problems.
And for god's sake dont die in the restriction and bloat up and block the rest of the cave for everyone else.
J
Last edited by rchrds; 08-11-2008 at 04:57 PM.
This is REALLY key! I add plenty of padding when I pass a restriction. If there is even the slightest doubt about being able to pass it the other way efficiently, I immediately turn around and do a back and fourth till I am comfortable. The stress of returning to a restriction after or during an emergency would really pile on. It is worthwhile to get to know your friend, you will be intimate with him.
Hans
Yeah, if you are taking your tanks off (and you actually have to...) buoyancy is not a concern.
We've got a cave here we dive on occassion, no mount only. We strap 2 AL80's together with extra long cam bands. We put a reg on eac tank and make the dive with no fins, no BC - there just simply is no point. Most off the time you are scraping your stomach & back.
Everyone spends the first nine months of life in water. The lucky ones make frequent return visits.
I have a 25# lead back weight tha twas built for me for just the sam ereason. I can also use any size tanks I need for the dive at hand form alm 40's up to 108's I use alm 80's all the time in the lake and I can take any tank off at any depth andnot worry about becoming positive, I will discuse this at the MO Workshop.
SLIM
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