Small Double's Kit

[scubafanatic]

Hey Bud, why don't you go get a dive or two under your belt, and get a padi card before you come around here trying to give advice on scuba rigs!
""Logged Dives: None - Not Certified""


Interesting choice of rig though, thanks for the suggestions.
Im thinking pound for pound, this rig will be equal to the weight of your set. I found some
40 alumin. tanks @ 15.lbs ech 3000 psi. 5.25 dia. And then there is the OMS steels.
With the carbon backplate, tank rings, and ultra light manifolds, im shooting for under 40# total.
Im also thinking hard about bitting the bullet, and adding some weight for comfort out of the soup with
a Poseidon. Besea. I know im adding floatent so to speak with this BC, and not a streamlined as a plain old back plate wing,
BUT i bet that half mile or so hike up the coast back home would be very plush with that BC!
Im willing to add a little more in weight/drag ect ect....for the backpack type fit this bc offers.
still think i can get in under 40 lbs, with a carbon backplate added to bc. and the rings in carbon also.
Would make for one trick looking setup!

...that Poseidon BC is a very rare bird...I've never seen one 'in the field'...but from every review/comment I've ever read about it, your right, it's very padded/floaty and pretty much the complete opposite of the slick/stramlined 'look' you're after......the main topside pressure point on a diver's body, for weight-bearing purposes, is the shoulder area, and it's easy to simply add those extra little modular should-pad strap cover thingies in those 2 critical spots, without puffing-up the whole rest of your BC with a big-*ss Poseidon BC.

 

[scubafanatic]

I think you're overly complicating it. Why don't you just wear a normal AL-80 with a jacket and sling a pony bottle for bailout in case of a regulator failure?

R..

...I pretty agree with this comment......I'm seeing very little 'minimalist' thinking in this project...... 50 ft. max depth dives, only needs approx 80 cu. ft. of gas, to which the scuba industry has provided a simple answer, the AL 80....for gas redundancy either sling (or tank mount) a 19-30 cu. ft. AL pony. (and if you tank mount it, you can even mount that one upside down, as the main tank will provide the tank mounted pony the clearance such that it won't be smacking the ground while donning/doffing your 'kit'.)

...somehow I'm not seeing any of us convincing you to not 'go all out' on this project and throw a bunch of $ at the problem so you can pretty much have a cool toy that nobody else has. ...or maybe you have age/physical issues (thus the 50 ft. max depth...the 'padding' concerns.....the 'safety' concerns...the 'I can't reach my tank valves unless the tanks are upside-down' concerns) ...but somehow feel you can compensate through the liberal application of $)

.....I'd suggest you maybe throw a bit of $ towards a dual-bladder wing instead, that's a very reasonable/easy safety upgrade. (I've got 3 such wings myself.)

.....for what it's worth, I've seen thsoe dual OMS LP 45 steels before...they look cute, but I don't think that's crazy, so I'd 'endorse' that bit of your plan...and I'd recommend you manifold them together...you can buy existing, off-the-shelf manifolds/bands for that.....with the tanks standing 'up' in the conventional way....but can't sign-off on the rest of the project....you are using a gold-plated sledgehammer to kill a mosquito, and as DA Aquamaster points out, all the new/custom bit's you plan to machine/assemble yourself is what we call a 'prototype', and somehow I'm not seeing you as a test pilot candidate...so I'm seeing lots of contradictions here.

 

[james croft]

...run the tanks 'upside down' ??? ...are you SURE this is a good idea ? ....how many other divers have you EVER seen....in real life...on TV...ect. doing that ? ...when you're gearing up, how will you get your tanks to 'self levitate' so you can strap them on/take them off without resting/crushing the regs/hoses ? (unless you're planning to use those goofy SS ring-stands that you mount to where the tank valves join the tanks ?)

There are many instances of "upside down" tank configurations in diving. Jacques Cousteau used them early on in scuba diving. Many Europeans currently use this set-up. I have used AGA doubles set up this way. Anybody who has studied diving history is aware of this. Like any set-up there are pros and cons for it but many divers like them this way.

Firefighters routinely wear SCBA tanks upside down with no problem and it makes the valve easier to reach and less prone to hang up .

 

[scubafanatic]

There are many instances of "upside down" tank configurations in diving. Jacques Cousteau used them early on in scuba diving. Many Europeans currently use this set-up. I have used AGA doubles set up this way. Anybody who has studied diving history is aware of this. Like any set-up there are pros and cons for it but many divers like them this way.

Firefighters routinely wear SCBA tanks upside down with no problem and it makes the valve easier to reach and less prone to hang up .

Hi James,

....for starters, I think I've even helped the OP achieve his dream, as although I'm 'against' the logic of the project, the OP apparently hasn't even considered the need for those 'tank-stand-rings' if he wants to dive 'inverted'...so I'm well aware of the existance of that product/solution (from a European dive catalogue, as I certainly have NEVER seen/heard of anyone in the Western Hemisphere manufacturing such a product......surprisingly, not even Halcyon makes it, I wonder why ?

...with respect to Jacques Cousteau, that was quite a while back, and much has been learned/improved/discarded in diving since those days.....Jacques Cousteau no longer represents 'best practices' in scuba for the year 2009.

...however, I'm sure the OP will be comforted to know you've officially approved his projected configuration in the event he plans to do any 'scuba-firefighting'.

 

[Nemrod]

I don't understand which part of this proposed rig is minimalist?

Here is a cylinder chart link, you may already have it but if not it will be useful to select tanks for your mini doubles project.

Scuba Cylinder Specification Chart from Huron Scuba, Ann Arbor Michigan

Two 40s are heavier than a single 72 alone and plus the double manifold is heavier than a single K valve and two regs are heavier than one so the total weight of your proposed "minimalist" rig will be considerably greater than that of my minimalist rig.

Like I said, I have a double aluminum 40/50/72/85 sets. So it is easy for me to pop them on scale compared to a rigged out 72 or aluminum 80. The double 40s rig weighs about the same (a few pounds more) as a single Faber steel 85 rigged out but carries less air.

If you must use a BC with your mini doubles rig you might consider looking into a horsecollar design, there are still a few around. There just are not any mini doubles wings I am happy with, it would be nice if Oxy Cheq would make a 24 pound lift mini doubles wing, a mini double Mach V concept. I also have used a older Sea Tec single wing with my mini 40 doubles rig but the wing just has to much capacity.

I also have a triple 30 rig I am working on very slowly.

Custom bands are available from Tech and Wreck I think it is on eBay.

Good luck.

N

 

[james croft]

Hi James,

....for starters, I think I've even helped the OP achieve his dream, as although I'm 'against' the logic of the project, the OP apparently hasn't even considered the need for those 'tank-stand-rings' if he wants to dive 'inverted'...so I'm well aware of the existance of that product/solution (from a European dive catalogue, as I certainly have NEVER seen/heard of anyone in the Western Hemisphere manufacturing such a product......surprisingly, not even Halcyon makes it, I wonder why ?

...with respect to Jacques Cousteau, that was quite a while back, and much has been learned/improved/discarded in diving since those days.....Jacques Cousteau no longer represents 'best practices' in scuba for the year 2009.

...however, I'm sure the OP will be comforted to know you've officially approved his projected configuration in the event he plans to do any 'scuba-firefighting'.

Your question to the OP asked if he had ever seen anybody use upside down tanls. While I don't necessarily recommend this to him it is still done by knowlegable divers past and present. It is probably not the best system for him as it would require custom hose lengths and hose routing.

I know the PADI police don't permit overhead donning and doffing of tanks but I do it if I am in an area where space permits. That is how you protect the valves on an 'upside down" tank. You don't just shrug off your tanks but you control them and lay them down.

Diving has changed and there are many improvement but I am constantly surprised at people who think there is only one right way to dive. I have tried a lot of different gear in the past 42 years I have been diving and often go back to the methods J. Cousteau used. I dive double hose gear with no BC or SPG and j-valve steel 72 tanks or smaller. I also use tech configurations with mixed gas, computers and full face masks with UW comm. I like to dive with many different set ups from vintage to modern but one is not necessarily better than the other. The fact that divers are always experimenting with equipment is how this industry comes up with new gear and methods. I suspect if it was left up to you we would all be diving plastic regs and driving the same model hybrids just because we came a long way since Henry Ford made the Model T.

 

[Scubabill]

Nemrod has been diving longer than most board members have been alive and more dives than God and is one of the board regulars. I'd take what he says pretty seriously.

Saving weight with things like carbon fiber bands sounds great, but puts a lot of time and expense into weight savings where you ultimately mauy need to add more lead or us an SS plate anyway. Strenght is important in bands but so is rigidity. Carbon fiber is stronger than steel on a pound for pound basis but you end up needing a lot more to get the same degree of rigidity in many applications and the primary function of tank bands is to keep the tanks aligned and immobile realtive to each other and the manifold.

SS bands are currently made for double 5.5" diameter tanks and standard width manifolds so I'd start there and then once you dive it get exotic with other materials if you are in some way not happy with the basic configuration. A less than perfect se of bands could result in a bent manifold and a leak, so go carefully if considering making your own.

------

+1 on keeping it simple. Just sling a pony with a single, or if you want light and low profile doubles, go with double LP 45's in a basic hogarthian/DIR rig.

Mk 17 G250V's are a good choice, just route the hoses straight down. I place the rubber "tops" of the regs inboard to maximize access to the valves and then route 2 or 3 hoses of one side of the reg. The right post will have the 7' long hose primary off the outboard LP port and the wing inflator hose off the inboard LP port crossing over to the inflator on the left. The left post will have the backup reg routed off the in board port and the dry suit inflator (if any) routed off the outboard port. The SPG is also routed straight down from the left reg.

Yea, i know he has dives! What guy would have no logged dives on his profile, and be giving advice about vintage dive gear? Please see the and read that as J/K!

AS for all the info from you and others....thanks for your opinions.
I agree after thinking it over some more, that the bp/w--mini doubles route is going
to be the best. AS i think this out more, i get side tracked on cool ideas, like the Be-sea BC. But i come back down to earth, and remember KISS.

I do like the 45s, and with a 'good fill' will be more then enough air for shore diving.
After more thinking, research...I think i will dive the duel 45's up to about 50 ft.
Anything over that, i will sling a 15-20 for emergency's only.
I looked hard for a duel bladder 20lbs lift wing for doubles....LOL!!!!
None on the market.....
Maybe we should make one! :cool2:


After thinking out the lighter components, i have gone away from that idea to, with your help! No reason to save 10 lbs, and spend 500, just to add some lead weight...
Kinda duh thinking on my part, but i was thinking about the walking and more out of the water comfort. But weight has to be carried one way or the other. Ok thinking out loud now!
Thanks again for all your help so far....

Lets debate the + and - of upside down mounting. My thinking was,
valves easy to reach for switching air, stopping leaks, ect ect.
Protection for the whole reg set, and more streamlined when swimming forward.
But mostly for the easy to reach valves in a pressure situation.
I still kinda like it to be honest......

 

[Scubabill]

I don't understand which part of this proposed rig is minimalist?

Here is a cylinder chart link, you may already have it but if not it will be useful to select tanks for your mini doubles project.

Scuba Cylinder Specification Chart from Huron Scuba, Ann Arbor Michigan

Two 40s are heavier than a single 72 alone and plus the double manifold is heavier than a single K valve and two regs are heavier than one so the total weight of your proposed "minimalist" rig will be considerably greater than that of my minimalist rig.

Like I said, I have a double aluminum 40/50/72/85 sets. So it is easy for me to pop them on scale compared to a rigged out 72 or aluminum 80. The double 40s rig weighs about the same (a few pounds more) as a single Faber steel 85 rigged out but carries less air.

If you must use a BC with your mini doubles rig you might consider looking into a horsecollar design, there are still a few around. There just are not any mini doubles wings I am happy with, it would be nice if Oxy Cheq would make a 24 pound lift mini doubles wing, a mini double Mach V concept. I also have used a older Sea Tec single wing with my mini 40 doubles rig but the wing just has to much capacity.

I also have a triple 30 rig I am working on very slowly.

Custom bands are available from Tech and Wreck I think it is on eBay.

Good luck.

N

Thanks for the chart newbie! LOL J/K (im sure you knew that the first time)
you just gave me the tank i'm going to use.
Did not know that OMS has a 5.5" 50 LP +
SO there we have it, 25" long 5.5" wide -1. empty
and with a GOOD FILL around 3000psi ech
im over a 100 in capacity, with redundancy for shallow solo stuff,
And for deeper stuff with a buddy only, i can sling a 15-20 tank for emergency
use.
Thanks again.

Vertex *Signature* Series Just did some checking, and this a a 30# doubles wings
wish it was 20# but might work......oxycheq

 

[james croft]

Oxycheq is good gear. Do not overlook steel 72 tanks. As far a minimalist goes a steel 72 is hard to beat. The bouyancy characteristics are well suited to being able to dive with no BC unless you are in colder water. Breaking down doubles is a hassle and you are going to spend twice as much on hydo and viz as you would on a single tank.

 

[Scubabill]

Oxycheq is good gear. Do not overlook steel 72 tanks. As far a minimalist goes a steel 72 is hard to beat. The bouyancy characteristics are well suited to being able to dive with no BC unless you are in colder water. Breaking down doubles is a hassle and you are going to spend twice as much on hydo and viz as you would on a single tank.

If i were just doing regular boat diving i would go single tank all the way.
But im going to be doing some shallow water shore dives solo, so i feel i want
the redundancy of twin tanks, separate. I can dive this rig in both situations,
shallow solo/deeper buddy with a sling. The only issue im fighting with now is,
why have two tanks if i only have a single bladder wing.....To be true redundancy,
i need a smallish dual bladder wing.

Question: Lets assume i can get a 20-25 lb dual tank, bladder wing made, with two inflater's.

How would one run the hoses, i would assume each tank has a lp hose run to a inflater? That way if i lost a whole side, tank, bladder, inflater at the same time (im reaching far i know) i could turn that tank off, and surface with the other tank/bladder. Is this the proper way of thinking?
By having the tanks upside down, i 'just about' lose the risk of bashing the manifold into something, and losing both tanks at the same time. And having the valves low and close to my hips, turning off a tank would be easy.

Next thought is, what happens if i get a free flowing inflater(assuming i have two)......you would have to shut down the valve on the main tank, which if any air was left you would lose. Is there a product valve that would allow me to shut flow off through the inflater upstream?
that way, i could still use the left over air in that tank if needed for a stop/ect ect.....