Doubling up lp121’s

[Tom Winters]

Can you carry 100lbs on your back?

Twinned 121's pumped to 3600psi, manifold, and 3" bands will weigh 120 pounds.

 

[JimC]

Twinned 121's pumped to 3600psi, manifold, and 3" bands will weigh 120 pounds.

Add another 10-15# for regs, wing, plate, lights, etc

 

[Dan Gibson]

HM 3" bands are more common for the larger tanks like LP120s but will fit the 104s. 2.5" bands are more common on LP104s.

The 2.5 bands are better for AL80, LP 85's, and smaller tanks. The bands are 7.25" in diameter.
The 8"-bands are usually the 3"-wide ones. Carrying that much heavy metal, they're 3" for maximum lateral rigidity.

 

[PerroneFord]

Wow,

And I thought my looking at 108s was extreme. I picked up a 121 in the shop a couple of months ago. I wouldn't want to carry that thing around as a SINGLE, much less a double.

I'm surprised no one mentioned that diving to 160ft *TWICE* on the same double set with no fills might not be the best idea. Are you turning your dive on thirds? How does the gas planning work here? Or are you planning on divng the equivalent of a single 121 for the first dive, and then the same thing again for the second? That plan seems a bit risky to me, but then I don't do dives at that depth. I've only been to 100ft once.

Best of luck with your tanks, but I'd be REALLY tempted to dive them as singles instead of doubles.

 

[MaxBottomtime]

For several years I used my PST lp120s doubled up with no problems. I had 3" Highland Mills bands, 6# SS backplate and 55# wing, plus my drysuit and a liftbag as backup buoyancy. I never had trouble in the water swimming them up, even with an empty wing. I used them for about 90% of the dives from my boat. I tried them on a few beach dives, but at 128# it got old fast!

I no longer have the boat, so I split them up as singles again. I can still get two hours on a beach dive with one of them.

 

[Solitude Diver]

Don’t let anyone scare you off the 120’s if you think you can physically handle the weight (without screwing up your back). They’re only heavy until you get into the water.

I dive twin PST HP130’s. Total package is about 145lbs (dry) plus about 18 lbs weight. If you dive them frequently, you can get used to the weight. I did about 50-60 shore dives in a row with them just to get used to them. (Cheaper than a gym membership, and much more fun). By the time I tried a single 130 again, I felt like I could sprint with it.

I am used to the twin set up now, and when I do wrecks, etc. I know I have the one necessity for handling emergencies …..time.

Good luck with the 120’s.

 

[IndyScott]

Thanks 4 the info. I have put together a set of highland 3in bands, seaeleit manifold, OMS stainless backplate and comfort harness, and an OMS red 60lb bladder.

I can’t wait to try it out.

I want to say thank every one for there advice.


Indy Scott