Hollis Explorer as the "ultimate travel RB"?

[kodo]

Hi!

I'm a PADI OWSI with roughly 600-700 dives all on OC. I've started to plan a 2-3 months dive trip (Australia & West Papua) beginning next year. As I become more and more dedicated to UW photo/video, I've started to think about RBs. I've initially been looking at the Poseidon MKVI *but* recently I find the Hollis Explorer a much more enticing alternative. The reasons for this are that it is based on Nitrox only which is readily available "all over the world" and that it works with a single tank (not two - O2 & diluent). Furthermore it looks very manageable and travel friendly and for my purposes a 40 meter max depth is not an issue as most of what I'd like to photo/film exists on shallower depths

If anybody more experienced in this matters could give me some feedback about this I'd be very grateful.

Many thanks in advance

 

[steady1570]

I know very little about the Explorer so don't want to comment on it, but with regards to your thoughts on being somewhat “simpler” with just one tank and nitrox, remember that you also need a scrubber material (whether pre-packaged or fill yourself), as well as some form of bailout tank. So one tank vs two might not be as big a differential as you might think after everything is considered. And whilst nitrox might be available everywhere, scrubber lime / cartridges might not or might be expensive, depending on where you are travelling. Also, AFAIK the Explorer is an SCR system, so you will still be creating bubbles to an extent, something to bear in mind.

Again, not trying to knock the Explorer (or any other unit for that matter), but just to point out that rebreathers of any sort do need quite a few additional things to make them “work”.

-Mark

 

[macado]

The above posted already answered it pretty well. I don't own an Explorer but here are my thoughts..

For what it's worth you're going to have the same problem with the Explorer as other rebreathers. Availability of tanks to fit the unit and sorb. If the places you're going to be traveling have both of these, you're good to go.

The difference being the Explorer's scrubber duration is only rated for 2 hours at 40m/130ft which is very low compared to most other rebreathers. This means if you're doing more than 2 dives a day (or longer recreational dives) you'll have to refill your scrubber. Not a huge issue here provided you have sorb available to purchase but it can be very expensive in remote places.

Availability of sorb: Most places don't stock it readily unless they're dedicated to technical diving. Ideally, you'll need to bring your own or do some searching to find it. It's "heavy" to travel with especially if you're backpacking. It's often sold in 44lb (20kg) containers however they do sell smaller 4.5kg containers that are easier for travel.

Availability of rebreather tanks: The Explorer uses 5L/40cu steel cylinder with an inline valve however I don't believe this is a "popular" sized cylinder you can find anywhere. I don't know if the Explorer can accept other more common sized tanks. Perhaps someone else can answer that? If you are doing more than 2 dives a day you'll likely still need 2 tanks so that negates the advantage of the unit only requiring a single tank.

Gas Availability: Nitrox and/or oxygen. The question is if they can boost high pressure (200bar) oxygen which would be needed for most rebreathers. Most places that can fill nitrox in theory usually have oxygen available. Exception is if they're using a membrane system for filling nitrox then they may not have oxygen cylinders. This is one advantage of the Explorer here is that it can function with 32%-40%.

Dives over 18M / 60ft require the use of a separate bailout cylinder. This one is pretty easy to solve as any AL80/12L (found at pretty much any dive shop) can be used a as bailout bottle however most divers would prefer something like an AL40 for recreational dives. You'll want to carry an extra bailout regulator and a stage kit with you for these purposes.

 

[tbone1004]

for the ultimate travel RB, I'd argue that the explorer is worse than any of the other units because it is limited in tank size to what fits in the unit. It is designed around a Faber 5l, which is not used anywhere else to my knowledge. The comparable diameter tanks are also not very common, and/or are too long. Luxfer 27 will fit, but is less than 30cf of gas, and I'm not sure I've ever actually seen one. Luxfer 40 is a very common deco bottle, but it is 6" longer than the 5l, so is too long for the unit since it is transverse mounted. The OMS45 and 50 are the same diameter, but the 45 is discontinued and the 50 is WAY too long to put in there. The nice thing is it is a fully electronic unit, it is cheap, and unlike the Poseidon, doesn't use a cartridge.

Better option? I'd grab a Kiss Gem, which is much more primitive than the Hollis, but it straps onto a single tank, so no custom harness, you can use whatever tanks are available, and there are no electronics to fail. It is $5500 with a Petrel instead of $5k for the Hollis, but you then have a Fischer connector Petrel which can be used on OC.
Alternative if you already sidemount would be to use the SCR Sidekick.

 

[Jordan Hardin]

Love the info I too am in the same boat and after extensive research think the KISS GEM is the best solution, some love there explorers but I have found people complain of the "bugs" it is almost to simple and self reliant, if you fail to do the start up ( aprox 40 checks I think) it will not allow you to dive, tons of sensors and electronics,you have to sort threw a mess. I was sold on the unit until a cave diver Advised me check out the GEM! Sounds nice to be able to mount to any tank and extend bottom time x3

 

[JohnnyC]

KISS GEM for ease of use. However, it's an SCR, and due to the design, you'll be venting gas out of the DSV with every exhale, it'll just be about a third of your normal exhalation. Basically, I don't really think an SCR does much more than give you all of the complexity of diving a rebreather, with minimal gain. And chances are, if you can't get O2, you're probably not getting sorb either, so it's sort of a useless endeavor anyway, unless you plan on bringing kegs of lime with you.

In my mind, for travel with a rebreather, you either take full advantage and go with a CCR and have the infrastructure in place, or bring stage rigging and make a deal with the dive off to sling a stage bottle on every dive so you're limited by NDL and not gas volume. Cheaper too. A set of Dive Rite travel stage rigging is $60.

 

[kodo]

A big "THANK YOU!!!!" to all of you for your comments. I will look into the logistics and see what I end up with.

Again, thank you all for you suggestions.

Cheers

 

[TechDeep]

Love the info I too am in the same boat and after extensive research think the KISS GEM is the best solution, some love there explorers but I have found people complain of the "bugs" it is almost to simple and self reliant, if you fail to do the start up ( aprox 40 checks I think) it will not allow you to dive, tons of sensors and electronics,you have to sort threw a mess. I was sold on the unit until a cave diver Advised me check out the GEM! Sounds nice to be able to mount to any tank and extend bottom time x3

Would hate to see you rule out the Explorer based on bad information. There is a ton of bad info going around here on Scubaboard, with the majority of it coming from folks that have never seen or dived the rig. I have not had any problems with mine. there are only 3 O2 sensors, and one optional CO2 sensor which to me is a huge bonus for the Explorer. That's hardly a ton of sensors. It's a great rig, I'm glad I bought it. Just don't rule it out without doing a tryout dive with an instructor.

 

[tbone1004]

that's why my argument against it was only based on being the ultimate travel RB. As a recreational SCR, it really isn't that bad, I don't like it personally because I think it is trying to fix problems that the diver needs to fix himself before you get on the loop, but it's not an inherently bad unit. I just think for a travel rb, the Kiss units make a lot more sense

 

[steady1570]

Ditto. As I said earlier, I don’t know much about the Explorer, but my point was more for this particular situation (travelling around for several months, photography as the main diving focus, no rebreather experience) the OP might want to consider whether a rebreather is the right tool at all… For me the “advantages” of a rebreather in this scenario would be lack of bubbles and extended no (or minimal) deco. As an SCR unit the Explorer doesn’t really fulfil the first point and by the sounds of it the extended dive time isn’t really that significant for the second. So for me that would point me to a CCR unit, but then you have the issue of lime / O2 fills etc, and at that point I would have to contemplate do I want the “benefits” with all the potential headaches or would I just be better to go with something that I know (because there is a learning curve for a ccr or scr and you certainly can’t just jump in and assume the unit will keep you alive)? Warm water, reasonably shallow diving… I suspect you can get an awful lot of mileage out of a single 12 without having to worry about cylinder's fitting or getting a scrubber fill!

Don’t get me wrong, I love my ccr, try to dive it everywhere and would never knock someone for wanting to use one, but I am guessing that if I was in the OPs position I would dive OC and spend the saved cash on a lime based cocktail or two


-Mark