Which dive compressor?

[hezi973]

Hello, I am planning to install a dive compressor on my 45' catamaran. Any recommendations for the right compressor?

My concerns are:
Weigh - the lightest the better.
Longevity - proven model that can last the marine environment.

Of course other factors like cost, size, parts availability, after sale support, noise level etc. play a part as well.

BTW, what those are using, 110 or 220 Volt?

Thanks in advance!

[Jammer]

Probably best to ask at scubaboard.com as there are more compressor owners there than here.

I would suggest starting your search with the Bauer Oceanus: https://www.bauercomp.com/applications/scuba/portables . The Bauer Junior II would be something to consider for reasons of price or limited available power, but is not as solid a machine.

Bauer has excellent worldwide support.

On a 45' catamaran most people would use a compressor powered by a gasoline engine. 120v and 220v electric ones are also available with various size motors. With a 120v compressor it takes roughly 45 minutes to fill a cylinder. Keep in mind that compressors are loud.

Mantus has recently started selling a small 120v compressor. They don't say much about it and I have been unable to find a diver or yachtsman who actually owns one. It's big and heavy for what it is and I think I'd rather have a Bauer.

Alkin has been around for a while and has a good reputation. I've just recently started seeing their portable compressors for sale. I don't know whether that's a new product for them or if it just wasn't widely advertised before.

I spent a lot of time and money on a compressor that didn't work and where parts and service were ultimately unavailable, so I would urge caution in dealing with used machines or lesser known makers that do not have a parts and service channel in countries you frequent.

A fact to ponder is that a dive compressor takes up as much space, weighs roughly as much, and costs more than 5 cylinders, so consider your needs carefully.

[Rumrace]

Are you filling 4000 psi tanks or 3000 psi.
I’ve worked with several compressors pretty much all 4 cylinder progressive. By law the compressor has to be surrounded by a secure concrete steel enforced wall. I worked on a boat call the Atlantic Clipper on Great Barrier Reef. Our compressor was massive in the engine room. We filled tanks on a steel frame on deck six up 4,000 psi. We had a fresh water clean tank beside it. If you think diesels crush engine mounts bend boats a compressor will be a riot. Amp hours on a compressor are impressive. Like 4 fridges

[Rumrace]

PS I was set for a wall dive in los Arcos in Mexico. 4 tank dive. On our way the Puerto Vallarta marina a tank (not ours) blew tanking out a 3hole brick rebar wall killing one employee and damaged our boat so we could not dive. It’s the tanks which are dangerous and why they require annual stamped visual and pressure test every 5 years. The older steels are all failing and a 20 year aluminum fails at the neck block.
At the price of aluminum bottles valve, a plastic bottom being around $300.00 it’s cheaper to have a land based compressor and run tanks out to your boat.

[Zanshin]

My Bauer Junior compressor has been going strong for 10 years and I use it a lot. In any setup the startup amps are high, so that has to be taken into account. My battery bank is big (over 1200Ah) and I will run my engine or genset to start up the compressor, and then fill my tank using the inverter and the batteries.

[Jammer]

Originally Posted by Rumrace

The older steels are all failing and a 20 year aluminum fails at the neck block.

The problem with older aluminum cylinders is due to the use of 6351 alloy used by some manufacturers prior to 1988 when the industry switched to 6061 alloy. Most cylinders made from 6351 have been removed from SCUBA service.


There is no reason to believe that aluminum cylinders manufactured after 1988 are unsafe, as long as the five-year hydro tests and annual visual tests are performed.


It is not true that older steels are all failing although steel cylinders in a salt water environment will eventually corrode and fail, especially if they are not galvanized, especially in daily use. Again, the five-year hydro tests and annual visual tests are sufficient to identify failing cylinders and remove them from service before they become a hazard.


Cylinder explosions resulting in loss of life are, tragically, common in countries that lack a safety culture and rule of law. Aside from the handful of fatalities from 6351 aluminum alloy cylinders that occurred before the hazard of this alloy were understood, I am unaware of any explosions of air cylinders in SCUBA service in the USA or Canada since the introduction of annual visual inspections in the early 1970s, and I have read through dozens of accident reports and searched carefully to try to find reports of such events.


Explosions involving oxygen cylinders and nitrox mixtures richer than 40%, while rare, do take place as a result of contamination of cylinders and fill lines with grease and oil. There are more of these in healthcare than SCUBA due to the sheer numbers of oxygen cylinders in medical service. From what I have been able to find there are one or two fatalities of this sort every year.

[Tupaia]

I have run a Maxair 35 std for 18 years. The only thing I have needed to do aprart from routine maintenance is repaint the frame. At 38kg it was and still is the lightest available. They now produce a SS model which I would choose.

https://max-air.com/product/maxair-35-gh-stainless/

They are noisy and require bleeding during fills but it has performed without issue and the Coltri head has been very reliable.


An 11 ltr tank takes about 25mins.

Things to consider an electric compressor will weigh the same but will require a fairly hefty generator which if you already have one big enough means you probably aren't that weight sensitive.

You don't say where you are based. So a tip is to buy tanks in the area you intend to sail. Australia won't test EU or US stamped tanks. The EU won't test non EU tanks. Asia, S.Africa, Caribbean and S. America will test anything. IMO a much more sensible approach as the reason for testing is safety not what stamps are on the tank. So buy tanks with as many approval stamps as possible.

[Jammer]

There are international standard UN tanks authorized but none have made it into SCUBA service in the USA yet.

[madprops]

Originally Posted by Tupaia

I have run a Maxair 35 std for 18 years. The only thing I have needed to do aprart from routine maintenance is repaint the frame. At 38kg it was and still is the lightest available. They now produce a SS model which I would choose.

https://max-air.com/product/maxair-35-gh-stainless/

They are noisy and require bleeding during fills but it has performed without issue and the Coltri head has been very reliable.


An 11 ltr tank takes about 25mins.

Things to consider an electric compressor will weigh the same but will require a fairly hefty generator which if you already have one big enough means you probably aren't that weight sensitive.

You don't say where you are based. So a tip is to buy tanks in the area you intend to sail. Australia won't test EU or US stamped tanks. The EU won't test non EU tanks. Asia, S.Africa, Caribbean and S. America will test anything. IMO a much more sensible approach as the reason for testing is safety not what stamps are on the tank. So buy tanks with as many approval stamps as possible.

I'm looking at picking up one Maxairs you linked.

If you were buying a new compressor now would you still buy the same one?
Anything i should know about aside from the bleeding during fills?

I Plan for this to be used in the middle of nowhere with long shipping times

[Tupaia]

Originally Posted by madprops

I'm looking at picking up one Maxairs you linked.

If you were buying a new compressor now would you still buy the same one?
Anything i should know about aside from the bleeding during fills?

I Plan for this to be used in the middle of nowhere with long shipping times

I would buy the same model but with the ss frame option.

[jordanbigel]

Originally Posted by Tupaia

I have run a Maxair 35 std for 18 years. The only thing I have needed to do aprart from routine maintenance is repaint the frame. At 38kg it was and still is the lightest available. They now produce a SS model which I would choose.

https://max-air.com/product/maxair-35-gh-stainless/

They are noisy and require bleeding during fills but it has performed without issue and the Coltri head has been very reliable.


An 11 ltr tank takes about 25mins.

Things to consider an electric compressor will weigh the same but will require a fairly hefty generator which if you already have one big enough means you probably aren't that weight sensitive.

You don't say where you are based. So a tip is to buy tanks in the area you intend to sail. Australia won't test EU or US stamped tanks. The EU won't test non EU tanks. Asia, S.Africa, Caribbean and S. America will test anything. IMO a much more sensible approach as the reason for testing is safety not what stamps are on the tank. So buy tanks with as many approval stamps as possible.

That Max-Air looks an awful lot like my (former) Coltri-Sub which was a fantastic unit and the smallest and lightest I could find. Some googling reveals they are in fact the same.

I love the stainless frame on this one. Mine was a painted steel frame and after 5 or 6 years the paint was a rusting peeling mess, so definitely the stainless version. I had the honda gasoline version and I plan to get another one soon - I don't have a big enough genset to run the AC version.

[Ballsnall]

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

[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.

[Jammer]

Originally Posted by Ballsnall

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

Right.


Help me out here. How are you going to make O2 and Helium aboard? Also, do you have a good recipe for making sorb out of flour and baking soda? Asking for a friend.

[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.