The Mares & Dacor HUB

[raxafarian]

Are all the hoses and fittings standard? Or do you bring all the spares required?

Even if you can change anything that may break, you have added numerous failure points for no gain.


It's not for me.

 

[Diver0001]

Ian Wigg once bubbled...
Hi

I've got a question - the one thing which crops up in pretty well every criticism of the HUB is the fact that if a hose splits you lose everything. Surely even on a 'standard' setup, if you have a hose fail you are going to lose all your air pretty quickly anyway and hence octo, and bcd will fail.

I must say I'm surprised at the comment regarding the inability to dump air whilst horizontal - works fine on mine (even works when on my back - not something I do regularly but I just wanted to see if it would!)

Ian

Ian, there are a couple of relevant things to say about the hose thing:

1) on a "normal" setup you can see and check your hoses. On the HUB you can't easily check everything, and in particular, the most important hose connections are hidden from view where many divers won't even think about them let alone check them.

2) the hose issues on the HUB are single-points of failure. That is to say that *everything* runs off of one LP port on your reg. Blowing a hose (which does in fact happen in practice) will simultaneously shut down or diminish the functioning of both of your regs and your inflation. Something biblical would have to happen to acheive this level of failure with a 'normal' kit.

Obviously breaking a hose will drain your tank, as you say, but with a "normal" kit you have less trouble reaching the surface again. Think about it. Suppose you're at 120ft on deep wall. It's a nice clear day, the visibility is excellent and you can see your buddy 10 metres in front of you looking in cracks with his/her light. And then..... without warning .... the main hose from your LP port to your splitter pops off the splitter. You know, the splitter you never checked because you probably didn't even know it was there..... One moment nothing in the world can compare to this and then BANG! Suddenly you're surrounded and confused in an explosion of bubbles. You draw a breath but water flows into your reg. Nothing is working, you can't breathe, you reach for your octopus but it's not working either, you try to inflate but you can't and in the confusion you've lost buoyancy control and you're at 120ft on a wall and sinking. You look for your buddy but he/she doesn't see you. You drop your weights to stop your descent. "Better bent on the surface than dead on the bottom", you think. You're going up. It's not possible to swim to your buddy anymore because you can't maintain buoyancy. You stay calm, you start going up and up gaining speed. You're trying not to hold your breath but your heart is pounding out of your chest and you keep getting water in your mouth because your reg is full of water. You try to blow off some air from your BCD but it's not working. The deflation is controlled by low-pressure port too! "Damn! I'm going to end up in orbit", you think to yourself wryly. You gain more speed before think about the shoulder dump. You dump some air and slow down. It's been 90 seconds and you still have 30 feet to go. You start finning like wild and reaching for the surface, you reject your reg. You're really struggling not to hold your breath now. Then WHOOSH! You break the surface and fresh air flows into your lungs. This is the happiest moment of your entire life! You get whacked but luckily a day in the chamber sorts it out. Good thing you were calm and controlled or you would have been dead. All of this is possible with a HUB.

Now compare that to what you would have done in "normal" kit.
Assuming you overlooked the failing hose when you put your gear on and it burst at 120 feet. Same scenario only the gear is different. To keep things fair suppose the hose to your main reg totally separated. One moment nothing in the world can compare to this and then BANG! Suddenly you're surrounded and confused in an explosion of bubbles. You draw a breath but water flows into your reg. You grab your octopus and quickly clear it. You're breathing again but you've started to sink in the confusion. A couple of spirts of air in your BCD stops your descent. You've regained buoyancy and you can breath, at least for the moment but you know you're running out of time. You swim as fast as you can over to your buddy. The swim takes about 30 seconds. You reach your buddy and give OOA and your buddy quickly hands you his/her octopus, looking very surprised at the sight of your bubble storm. A few seconds later your air runs out and the bubble storm stops. Your buddy signals you to stay calm. You take a minute to catch your breath and then abort the dive and make a controlled ascent together. That night you sit in the bar and toast to your health.

OK, it sounds pretty dramatic but nothing I wrote here is impossible or even needs much imagination. Mark my words. As the HUB's begin to age some incidents like this *will* happen. Obviously having "normal" kit isn't a guarantee of survival either but given the options. ....... I know what I would choose.

Cheers,
R..

 

[MikeS]

I’m not a hub fan. I think that conceptually it is a great idea that didn’t turn out well in practice. Nevertheless, I feel obligated to play the devil’s advocate in regards to R’s scenario.

While I have never seen a LP hose burst my understanding is that, the tank will be empty in less than a minute whether your regulators are connected to a single LP port or multiple ports that are connected internally. If a LP hose burst, I don’t think I’d waste any time attempting to switch to my alternate second stage amidst the cascade of bubbles. I’d either switch to the bailout bottle or get real cozy with my buddy real fast.

Rather than thinking about adding air to your BC you should be thinking about dumping air as you go to the surface. In fact, I would think that it would be a challenge to prevent a runaway ascent. As air escapes from your tank, you will continue to become more positive until the tank is empty.

Additionally, if I “lost” buoyancy control and started to sink, I think I would swim up to where I lost it and retrieve it rather than adding air.

Mike

 

[Ian Wigg]

Isn't the single point of failure argument, whilst on the face of it valid, somewhat negated by the fact that anyone diving on a single is risking that no matter what bc/reg system they dive. Especially as the o-ring on the tank valve is probably the most vunerable and likely to fail. Isn't that one of the main reasons why manifolds have isolating valves?

Ian

 

[leadweight]

Failure Point is part of the DIR vocabulary, designed to scare divers into their way of doing things. In practice the hose routing on the hub, or the inflation system has not proven to be unsafe. Scubapro has adopted the pneumatic inflation system for the Classic. With their marketing clout it is likely to spread. It true that the exact right blown hose could put you out of business, but a blown o-ring is more likely and that will lose your air in a hurry.

I must admit that integration does have its negatives, either a regulator or a BC problem with a HUB means the diver must replace both the BC and the regulator at greater expense. However, to a certain extent this problem is faced by divers who use integrated octopus inflator devices like the Air2.

Personally, I think that keeping the Octopus in a pocket is a very poor practice. An out of air diver will just grab jour primary and leave you fumbling for the octopus.

While using this board it is wise to remember that it has been taken over by DIR types. They are a small minority and have views that differ from the diving mainstream. If you are a recreational diver your needs are different from theirs.

 

[WreckWriter]

leadweight once bubbled...
While using this board it is wise to remember that it has been taken over by DIR types. They are a small minority and have views that differ from the diving mainstream. If you are a recreational diver your needs are different from theirs.

It's also wise to remember that there are a certain few strokes here that are simply playing up the anti-DIR garbage as a means of stirring things up.

WW

 

[Ian Wigg]

To be honest this is the first thread where the hub has been mentioned where the discussion hasn't degenerated to the 'death trap' level. I've found the arguments both ways to be considered and reasonable which believe me, as a hub owner, can be a rare thing.

In terms of replacing the whole thing if it fails - it is actually possible to convert the bc to a normal dragonfly if you wanted to or, if the bc died, you could use the regs on their own.

In regards to the octo, i've found that as long as your buddy knows where it is there isn't a problem. If they're not happy with it just move it.

Ian

 

[leadweight]

WreckWriter once bubbled...


It's also wise to remember that there are a certain few strokes here that are simply playing up the anti-DIR garbage as a means of stirring things up.

WW

Ah yes, stroke, another word from the DIR scare-ya vocabulary.

Stirring things up? So there is only one way to do things and that is the "right way" as in DIR? At least I don't engage in comparisons to certain evil organizations, the names of which should not even be mentioned around here. I honestly feel that DIR, while very relevant (but not 100% required) in caves and other sorts of diving that is outside the industry definition of recreational diving, lacks relevance to recreational divers, particularly the warm water crowd. You can dive DIR anywhere, but that does not mean you have to use it when it is not needed. Extra safety, OK, but I don't wear a helmet when I drive my car with 3 point belts on and airbags front and side.

Some of the technical divers need to stop assuming everyone is just like you.

 

[Diver0001]

Ian Wigg once bubbled...
Isn't the single point of failure argument, whilst on the face of it valid, somewhat negated by the fact that anyone diving on a single is risking that no matter what bc/reg system they dive. Especially as the o-ring on the tank valve is probably the most vunerable and likely to fail. Isn't that one of the main reasons why manifolds have isolating valves?

Ian

Ian,

Perhaps my point got lost in the story.

This is a story about risk management. Risk involves two things. First of all the chance of something happening and secondly the consequences if it were to happen. Proper risk management, therefore, involves reducing the chances of a problem and making it as easy as possible to deal with if it does happen. MikeS had a good point about a bailout bottle. Bailout bottles are all about risk management (albeit a solution that can lull some people into a false sense of security and cause them to work less on avoiding problems).

Getting back to the HUB. I'd say that the chances of hose problems on a HUB are higher than the chances with traditional kit for two reasons that I've already mentioned. (1) checking your hoses is more difficult and I believe that most HUB users won't even bother and (2) the splitters add extra things to go wrong. (strike one)

Furthermore, I'd say that the consequences of such a problem are also more serious as I tried to illustrate with my previous post (strike 2). Diving will never be risk free and since safe diving is about risk-management I'm against willing accepting elevated risk for no good reason. Since the HUB doesn't offer a really compelling reason to accept the extra risk I'm against using it (strike 3).

In short, the HUB's hose routing gives me the heebiejeebies and I sincerely don't think it's fit for purpose. It might not break down on the first dive when it's all shiny and new from the store but in 10 or 15 years time we'll see the results. I'm hope I'm wrong.

R..

 

[O-ring]

I honestly feel that DIR, while very relevant (but not 100% required) in caves and other sorts of diving that is outside the industry definition of recreational diving, lacks relevance to recreational divers, particularly the warm water crowd.

Some of it is relevant...even the warm water weenies we met on the boat in Bonaire were enthralled with our spring straps. They kept asking questions and wanted a demo...they left the boat talking about ordering some since it seemed so much easier to them to get their fins on and off quickly on shore exits.

On the flip side, they referred to us as the "gear guys" and one woman said that she "couldn't wait to see us put all that stuff on"...hehe.