Which dive compressor?

[spoolin01]

Originally Posted by Jammer

They're the standard because they are cheap. Most of the ones being sold now are made in China under the Metal Impact brand.

I suspect they are currently fairly standard also because for the longest time they were all but the only offering at the dive shop, and all but the only tank a new diver would see in the charter and rental industries.


Don't know the origins of the sizing decision, but I've always suspected it had to do in part with the inherent idiot-proofing that 77 cu ft offers, with respect to over-staying bottom time over a wide range of recreational diving depth. Especially if the diver was observing the highly conservative reserve PSI requirements of a lot of dive ops.


It's interesting to speculate whether the 45min to 1 hr cap on bottom time commonly imposed by dive ops was cause or effect of this tank standard.

[D_to_L_over_400]

I owned/used Bauers on boat/home/RV trips and used a Mako at work. I like bauer and they are everywhere but my pet peeve is that they phase out parts leaving the unit useless.I have one that was “phased out” and is compact and perfect and dread the day I can not find some stupid little warn part. But bauer is not worse than others, surely, they have a big support network. Stick with compressors that share parts with the firefighter/EMS compressors.Those tend to stay on the market longer and parts are available. But rarely are EMS compressors small, rarely… not never… some ARE small and portable. Or a model that has large market share unchanged over many years.
Think ahead…how will I use this if they phase out parts?Can I add a filter stack externally if the company phases out the filter, Can I fix it with parts from other models or in remote hardware stores.Etc?I feel an expensive compressor is not killed by use as much as phased out parts.
Coltri has been impressing me. The variations on the MCH-6 compressor have been around a long time and they do a good job keeping parts available. I never owned one. They are expanding in business with the new market of paintballers (it appears). I will try to find the name for the new MCH-6… looks to be the same but Colti said it was different.When I replace my old Bauer I will likely buy Coltri.
If I read all this right the O.P. ordered a “NEW” boat so the following does not apply: If buying used ensure that nothing was painted. You might be able to remove the paint, ok fine.But paint prevents heat exchange and shows the owner was an idiot and was trying to cover up dirt.The little compressors on ebay and amazon claiming they run off 110v and compress overnight any scuba or paintball system and are only as big as a lunchbox…. I feel safe assuming that is not possible.I assume these are a joke and will take days to complete the claimed task.Might over heat.I hope someone proves me wrong.Please report back here.
IMHO. Running off electric is a waste of energy on a little boat. Maybe you are one of those jerks who rolls into a quiet anchorage and destroys the peace with a fricking generator or genset running for hours. If so, fine, maybe electric will work for your lifestyle. You said "solar array and Lithum bank.... maybe?.... compressors draw a great deal of load especially at startup. I would get a portable movable unit with belt drive to a small engine. A small diesel engine if your boat uses diesel. (Coltri has a diesel option.Bauer might. Little single piston yanmars or lambardinis are frequently found at military surplus auctions). Or if your dingy is unleaded/petrol do the manufacturer’s unleaded/petrol.Or if your tender is 2stroke… macgyver a 2stroke engine. Think about the energy loss running off electric. It will be huge. Every time you switch from mechanical to electric to chemical(batt) or other combination you are losing energy and creating heat and increasing your carbon footprint. Consider driving off the front pulley of your main engine if you really want it below deck or you want to make use of energy when warming the engine(s) or underway at slow putter. Since you are on a cat, OP, you need worry less about appropriate upright running angles. Watch the RPM x pulley diameters. Compressors have specific RPMs that they need to run at. This is not just about efficiency.Too fast is too hot.Too slow might reduce lubrication. If someone says do hydraulic off the main engine quiz them…. I have had many people say hydraulic is the best but when I do the math I would need a giant keel cooler or a giant heat exchanger. True even for the Kidi Cornilious compressors (designed to be hydraulic power).But I could be wrong and this would be a great way to move the unit to the bow/deck (upwind and cool) when used but still use the main engine when underway or warming. But you (OP) claim to be sold on electric so please post the final results and capability when you are done so we can all learn from it.

Regardless report back and tell us how it went.
I am rebuilding my Bauer to run off the front (belt) of my engine on the boat. Smaller boat than I am used to. Not as easy as I hoped.If you have a “new” 45’ ft cat you have space for a little engine on your compressor.As much as below deck is convent in theory, If you have the space and the strength to move it a little portable unit that can be moved to the bow (fresh cool air) when compressing.Moved off the boat for service. It is logical if you have the space.
Good luck! Report back in the years to come with your findings, OP.

[hezi973]

Originally Posted by Tupaia

At 57kg compared to 38Kg for the MaxAir this is much heavier.

Can you send link/s with spec?

So far the names that came up are:

* Bauer Compressors Junior II Electric Drive
* LW 100 E1
* Nuvair MCH-6 / 3E Coltri
* MaxAir 35 Electric
* Mantus dive compressor

I am not sure I missed a popular option. Not I need to go through this list and pick one.

[spoolin01]

Originally Posted by Idaho

Today I put the Rix Sweet Air oil-less compressor on the boat.

After running around Guaymas a full day to source the needed stainless and rubber mounting parts, I have what is needed to engineer and build a set of vibration isolators to mount the compressor securely.

Tomorrow will have it mounted and tested.

Two weeks and one day until cast off.

I've only ever owned two of the Rix oil-less compressors, never an oiled brand, but I have to say I love the low maintenance and minimal filtration requirement involved. My 6A has yet to require a rebuild but if parts become an issue, that will be the first disappointment.

[Tupaia]

https://max-air.com/wp-content/uploa...ric_Baldor.pdf

[hezi973]

[QUOTE=Tupaia;3700037]https://max-air.com/wp-content/uploa...ric_Baldor.pdf[/Q

[Cpt Mark]

I have a 32 year old Bauer compressor similar to the Jr 2. Works perfectly. Came with a gas engine which I do not want as my compressor is located in an enclosed space. I bought a cheap chinese diesel engine, single cylinder for it. My previous Bauer compressor had a yanmar diesel engine.

Bauers are probably the best in the world for small compressors. Great service and parts availability.

I have worked on many dive boats and they filled tanks n deck in open air. Yes there is the story of the odd tank exploding but it is very rare. I expect to get a lot of requests to fill others tanks when I go cruising. Those tanks will need to have current inspection tags. Why take chances?

[D_to_L_over_400]

For Archival reasons I will add: The Coltri MDH6 mentioned by myself and others above was perhaps rebranded as the ICON 100 EM. (with EM maybe being the powers source not particular to the compressor, maybe)

[flightlead404]

Originally Posted by Ballsnall

Lots of advantages to just go with a rebreather over tanks and compressors.

Yellow box of death?


I won't dive a rebreather until they fix the O2 sensing problem. When divers like Wes Skiles are dying on rebreathers I'll pass.

[flightlead404]

Originally Posted by skipmac

Regarding O2 clean risks, there's a lot of talk and some shops really paranoid about it but I have heard of very, very few actual fires or explosions. As a friend once pointed out, if O2 was that dangerous then you would see welding shops blow up every week as they are notorious for poor cleaning protocols.

One of my tech diving buddies had a serious O2 problem but it resulted not from the tank itself, but from contamination in the HP gauge or hose. Seems when checking the O2 pressure, opening the valve let pure O2 into the contaminated gauge which promptly blew, enveloping my bud in a cloud of O2 resulting in 2nd and 3rd degree burns over much of his torso and arms.

Honestly I don't see the utility in doing tri mix or even nitrox fills on board. Either you have to carry K bottles, which are large, heavy, and dangerous if they get loose, or you have to make O2. At that point, I'm just using the local shop.

I went round and round on this myself, I decided I'm not even carrying tanks. Since I'm not filling on board, I have to go to a dive shop anyway, so why not rent tanks from them at $10 or whatever.

I have seen a tank blow on an air fill, but this was in cave country and they had put in double burst disks and were regularly filling to 5,000 psi or something crazy.

I think if I were filling on boat, just in case I'd use a long fill hose and suspend the cylinder a couple feet below the surface of the water.

[Jammer]

Originally Posted by spoolin01

Don't know the origins of the sizing decision, but I've always suspected it had to do in part with the inherent idiot-proofing that 77 cu ft offers, with respect to over-staying bottom time over a wide range of recreational diving depth.

Correct.


The first widely-promoted cylinder size was the steel LP72 which typicaly held 71.5 cubic feet. The thought was that an average diver could not meaningfully exceed NDL (no-decompression limits) with that amount of air. During this era, it was accepted practice to breathe the cylinder until empty, in part because SPGs were not affordable, and in part because the ability to surface on a single breath with an empty cylinder was emphasized as a core skill in training. This approach led to many injuries and fatalities from AGE and DCS and has since been replaced by more conservative training.



In actual fact, even with an LP72, an experienced diver can easily overstay the limits on repetitive dives, even with just two dives; some divers who have unusually low air consumption can overstay the limits on a single dive.



When aluminum cylinders for SCUBA diving were introduced in the 1970s, one of the selling points was that they were somewhat larger than the LP72s then in widespread use.


Whether 500 psi is too much or not enough to end a dive with is a topic as controversial as anchor selection.

[Jammer]

Originally Posted by flightlead404

I won't dive a rebreather until they fix the O2 sensing problem. When divers like Wes Skiles are dying on rebreathers I'll pass.

I won't either for a wide variety of reasons chief among them being that the dives I enjoy the most are shallow dives. If that changes, well, we'll see.


The rebreather apologists will tell you that rebreathers are as safe as twinsets when you control for the amount of bottom time and the depth. I don't know whether I believe that or not.

Originally Posted by flightlead404

Honestly I don't see the utility in doing tri mix or even nitrox fills on board. Either you have to carry K bottles, which are large, heavy, and dangerous if they get loose, or you have to make O2.

There are some nitrox membrane systems that are reasonably safe and compact that will give you 40% without much trouble.

I went round and round on this myself, I decided I'm not even carrying tanks. Since I'm not filling on board, I have to go to a dive shop anyway, so why not rent tanks from them at $10 or whatever.

When you have your own tanks you don't have to visit the dive shop before your dive. You don't have to visit the dive shop after your dive. You just have to visit a dive shop at some point between dives. Some dive shops will not rent tanks to solo divers. By getting fills between dives I can honestly say that I'm not sure where I'm going to dive next or who I'm going to dive with.

I have seen a tank blow on an air fill, but this was in cave country and they had put in double burst disks and were regularly filling to 5,000 psi or something crazy.

I would like to hear more about this because I have a large number of cave divers who have told me that this has never happened in the entire history of cave diving. Please PM me if you don't want to post details.

[Pete7]

Originally Posted by Rumrace

The tank valve is all you need to change. The US lazy valve stands up way better than the EU or Aussies but they run 4,000 psi and are typically steel 74Cu
I have twin 125 Steel sets. Shipped to Australia and to Carribean no worries on mixed gas or air fills.
The standards for scuba tanks testing is the same everywhere.

What utter nonsense, why do you keep answering threads with information that is at best misleading or sometimes down right dangerous

European cylinders are sized by their water capacity in litres for start. Also I hope you are not suggesting fitting a US cylinder valve to a European cylinder. They are completely different thread sizes.

Finally for 2 decades, the A frame valve across Europe has been fading out in favour of DIN screw in valves which have captive o rings.

[Pete7]

Originally Posted by Jammer

I would like to hear more about this because I have a large number of cave divers who have told me that this has never happened in the entire history of cave diving. Please PM me if you don't want to post details.

I have had a burst disk fail about 1985 time. I had bought the cylinder in the UK second hand and had it tested. Stored in a wardrobe it blew about 1am whilst I was a sleep and emptied the clothes out of the wardrobe rather quickly. Gave me a bit of a fright too Turned out to be a US valve with a burst disk and whilst members of the club had heard of them no one had actually used one. Whole Valve replaced pronto.

[skipmac]

Originally Posted by flightlead404

Yellow box of death?


I won't dive a rebreather until they fix the O2 sensing problem. When divers like Wes Skiles are dying on rebreathers I'll pass.

If the O2 sensor (and associated electronics) is your only objection look into the Halcyon RB80. All mechanical, no O2 sensor or electronics to short out or otherwise fail. But ain't cheap.


https://www.halcyon.net/rb80,473,en