Why is using the 32% nozzle on the dolphin bad?

[kennethw]

caveseeker7 and Camerone, thank's for the tips and pictures.

From what I can see from the pictures posted by caveseeker7, the 50 cu ft bottle is a Luxfer which is about 19". My bottles are British Dive Team 7.0L bottles which are taller than by 30 cu ft Luxfers which are already nearly 22". I shall have to try the configuration again.

The second picture from caveseeker7, wow, 3 huge bottles; which proves that even larger bottles work too. I guess you run out of scrubber life before running out of gas.

Again, thanks a million.


P.S. Sorry for going off-topic and hijacking the thread for a little while.

 

[Whaam68]

I used my Dolphin with the 32% jet for a week in Scapa flow down to 40m & it worked just fine. You definately need a bigger tank on that jet as the flow rate (over 15lpm) is very (the flow rates are very conservative), breathing hard I was struggling to get the bag mix below 30%. I use a 10Litre butt mounted in the usual place. It's a little wider than the stock Aluminium 5 litre but not much as its steel & thinner walled & double the capacity. (Only) If you have the Oxy 2 & once you've figured out how much 02 you are metabolising you could try running leaner mixes through the jets to improve the operating range. For example running 35%-36% through the 40% Jet (just over 10Lpm) gives me around 31% in the bag. On a really hard swim the lowest I got the mix to using this combo was 27%. A 10 litre will run somewher between 2-3 hours depending on the profile of the dive. I paid extra for the 32% but am finding the 40% & 50% jets far more useful.

 

[Life-Is-Good-Diver]

Real dump question, please.....How do you mount your 50 cu ft bottles?

A 50 cu ft is pretty big, so placing it where you would place the existing bottle holder at the bottom of the shell makes the tank protrude out the sides way too much. Placing it on the side of the shell (like the bail out) is possible, but the bottle is heavy and I am afraid the plastic cannot take the weight and the whole rig will be unbalanced (unless you use a 50 cu ft as your bail out too).

I've tried placing the bottle like a stage, but don't like that because in an emergency, it may be difficult to remove the unit to, say, remove entanglements.

I've built a frame for my Dolphin with tank mounts on either side, where I'm using 30 cu ft bottles for O2 and Diluent when diving it CCR.

Otherwise, I have a 5L Drager bottle which is OK.

I also use an alum 50 on my Dolphin, but it matches my side tanks as well, so it dosnt stick out.

My set up consist of a Alum 50 , with a 13' pony on one side , which i run my B/C, dry-suit, off of, and on the other i use a 19' pony for O/C bail out on dive's 60+, asnd for shallower dives, i just use two 13's , (one on each side) and one 13' just for O/C bail out.

I was even thinking why more people on the Dolphin's use a Steel 80 one the bottom for deeper dive's? Im going to try using a steel 80 vs the Alum 50 , with the Alum 50 i get about 3 hour's out of, 3 dives to 60' on a reef, where im hoping with a Steel 80 i could get longer bottom times below 80', and maybe get 4+ hours out of 1 tank, and never have to change the tank, just the scrubber after 3 hour's+.

I also and trying the converter from Oxycheck, so hopfully i will be able to just buy a 200 bar Din/ Yoke Thermo K valve, and add it to a tank, rather then spend $300+ dollar's just for a drager tank.

But to answere your orginal question, with a alum 50 , yes it will stick out, but it's not that much, and with two tank's mounted on each side of my unit, the Alum 50 fit's perfect.

 

[Life-Is-Good-Diver]

I just mount the 50 cf bottle on the bottom in place of the standard 28 when I use one, which is fairly often, actually. The only difficulties are that the strap velcro isn't long enough (no big deal), and the hoses stretch to their limits when feeding the dosage unit.

I use a 19 cf bailout, mounted so that the bottom of the bottle just sits above the 50 cf on one side. The other side of the unit has a small argon bottle (6cf) to keep me warm in the drysuit. The 50 cf doesn't really stick out any farther than the edges of the two side-mounted bottles.

The Drager shell is really flimsy... for each of the mounts that I used, I fashioned a backing plate for the inside of the shell that helps distribute the forces across a larger area of the plastic. I watched quite a few Dolphins come into my LDS for service that had large fractures down the sides from people who mounted bottles without reinforcing the mount point one way or another.

FWIW, a small metal plate works wonders and can be quite thin. Personally, I just happened to have scrap quarter-inch thick ABS plastic lying around at work, so I cut two plates out with a laser and used them as backing for the mounts. It doesn't take much, but you have to do something or you will crack sooner or later.

Have any pictures of your unit, would love to see them, as i use two tanks on both sides also, thanks