Hollis SMS 50, what am I missing?

Can someone explain the logic of Hollis putting the inflator hose attachment point at the bottom end of their BC? I don't get it. Every other BC designer in the world knows that air rises, so the logical place to put the dump valve on a BC is at the top. Not so the folks at Hollis. They put it a little south of half way down their bladder. Plus they outfit their SMS50 with a very short inflator hose. Granted, you probably aren't going to put a ton of air in the thing, but if you do there is absolutely no way to get all the air out without standing on you head and somehow managing to get that short little hose higher than the valve so air will flow out. It just doesn't make sense. Hollis does provide a dump valve in the bottom corner of the bag. You have to find and pull the little cord that pops out of one corner. But, cords do break. Valves to stick open. When I'm caving I want a redundancy.
I've written Hollis, but they've chose to ignore my question.

Richardthesecond:

Can someone explain the logic of Hollis putting the inflator hose attachment point at the bottom end of their BC? I don't get it. Every other BC designer in the world knows that air rises, so the logical place to put the dump valve on a BC is at the top.

Click to expand...

Yes, air rises.

But... the diver isn't vertical. The expectation is that they will be in proper horizontal trim. That puts the inflator where it's needed.

It is also located there, specifically for overhead environment diving - as it protects the LPI elbow from damage/abrasion.

It is also located there as it permits efficient hose routing from the sidemount cylinder (top mounted LPI being great at receiving a hose from a back-mounted cylinder... but not-so-hot when the regulator/hose source is under your armpit...go figure).

As for "every other BCD designer"... this is sidemount... it's different...

UTD

Stealth 2.0

Razor2

Nomad Lt

Armadillo

Recon

Richardthesecond:

They outfit their SMS50 with a very short inflator hose.

Click to expand...

It's not short... but it does lack flexibility. Can be hard to reach the mouth for oral inflation. Other rigs have a more flexible (but not longer) hose. I use a Halcyon-type corrugated hose (oval cross-section) and that's plenty flexible. It's paired with an 8" LP hose routed from the end-port of my left regulator - very direct, very clean routing.

Richardthesecond:

there is absolutely no way to get all the air out without standing on you head and somehow managing to get that short little hose higher than the valve so air will flow out. It just doesn't make sense.

Click to expand...

With proper training it will.

First - dive in horizontal trim... there's half your problem solved.

Second - a slight roll sideways, easy to dump the air, whilst retaining longitudinal trim.

Richardthesecond:

When I'm caving I want a redundancy.

Click to expand...

Will be a while yet, I am guessing. You'll have cracked it by then...

Oh, by the way... Hollis has released a "Sport" version of the SMS50 - designed for the needs of open-water sidemount divers. That places another port on the top of the BCD - giving the diver option to route the pull-dump and LPI from either top or bottom.

Again... that's for open-water divers though. There is still an expectation that overhead environment divers would prefer more protection for the LPI elbow..



Hollis "SMS" sidemount systems have been designed not just with cave divers in mind, but any sidemount diver. The new SMS50 "Sport" is no exception. Built for sidemount only, this kit can be used in any environment from open water to overhead. Includes an adjustable, one size fits most harness based on a minimalist design; ideal for traveling sidemounters. First of its kind harness, wing and plate in one with an over the shoulder hose routing for recreational sidemount divers. Like all Hollis SMS harnesses, ready to dive out of the box.

As always, Andy "ditto". Maybe one day I might post before you.

As for the OPV, I haven't seen an SMS 50 and don't know if it uses a standard OPV. If it does, though, replacing it with the one from DSS would make sense--I have them on every wing I own, including the Stealth 2.

As Devon said, this is sidemount... Different to backmount. There are models of the Sms50 that have the inflator on the top of the wing. If you are in proper horizontal profile then all you have to do is stick your arse cheek up a little and use the pull dump located on the side opposite to the inflate.

DevonDiver:

Yes, air rises.

But... the diver isn't vertical. The expectation is that they will be in proper horizontal trim. That puts the inflator where it's needed.

It is also located there, specifically for overhead environment diving - as it protects the LPI elbow from damage/abrasion.

It is also located there as it permits efficient hose routing from the sidemount cylinder (top mounted LPI being great at receiving a hose from a back-mounted cylinder... but not-so-hot when the regulator/hose source is under your armpit...go figure).

As for "every other BCD designer"... this is sidemount... it's different...

UTD
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Stealth 2.0
View attachment 151850
Razor2
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Nomad Lt
View attachment 151852
Armadillo
View attachment 151853
Recon
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It's not short... but it does lack flexibility. Can be hard to reach the mouth for oral inflation. Other rigs have a more flexible (but not longer) hose. I use a Halcyon-type corrugated hose (oval cross-section) and that's plenty flexible. It's paired with an 8" LP hose routed from the end-port of my left regulator - very direct, very clean routing.



With proper training it will.

First - dive in horizontal trim... there's half your problem solved.

Second - a slight roll sideways, easy to dump the air, whilst retaining longitudinal trim.



Will be a while yet, I am guessing. You'll have cracked it by then...

Click to expand...

Many thanks, I guess it's just a matter of more practice.

cmcdarris:

Richard, I just bought the sms75 and I agree with your 2013 post. The dump valves make no sense to me either. I am considering sending it to a 3rd party who can add dump valves in the proper location. Have you gotten used to it, or what was your "fix".

Thanks. Charlie

Click to expand...

my first thought when reading this was "equipment solution to a skill problem". The dump is correctly placed, if you are finding the unit an issue, it's likely your trim.

Yes, this thread sort of blows me away. I've used the SMS 50 for my Mexico cave diving rig for about 4 years now. It's ideal with a pair of AL 80s and an AL 80 stage. I've NEVER had issues with air trapping. But of course I dive with level trim like all "competent" divers.

Ideal for AL80s? With a buttplate, no front D-rings, weight pockets that don't fit most cast weights, no adjustability of spine length?

I used to get a lot of students with them (prior to XDeep, Apeks etc making decent rigs) and, without exception, people grew to hate them...