Size the compressor to refill the entire guest load within the surface intervals, not overnight, then add a second unit. A dive liveaboard whose compressor fails at sea has no product left to sell, and there is no service support where you will be. Redundancy on this system is not luxury, it is the difference between a delayed dive and a terminated trip.
The sizing calculation
Start from the operating profile: number of divers, dives per diver per day, cylinder size, and how much of each cylinder is actually consumed. Multiply out to a daily air volume, then look at when that volume has to be delivered. On a typical Komodo schedule with three or four dives a day, the fills have to happen between dives, which compresses the available window considerably.
A compressor sized to deliver the daily volume across twenty-four hours will not keep up with a schedule that needs most of it delivered inside a few short intervals. Size to the interval, not to the day. Then add margin for the trips where every guest dives everything, for cylinders being topped rather than emptied, and for the days a guest brings their own larger cylinders.
Redundancy
Two compressors is the standard we recommend and the standard the better boats in this fleet already run. They need not be identical; a main unit with a smaller backup capable of maintaining a reduced schedule is a legitimate arrangement and costs less than two full-size machines. What matters is that a single mechanical failure does not end the trip.
Carry the spares that would otherwise strand you: filters, valves, belts, seals and the service items specific to your machine. Labuan Bajo is a supply endpoint, not a hub — see yard and supply logistics.
Storage banks
Bank storage lets you decouple compressor running time from fill demand. Filling from a bank is fast and quiet, and the compressor can then refill the bank at a convenient time — ideally while the generator is already running for another reason. On a boat where you want to avoid running machinery overnight for guest comfort, banks are what make that possible. Size the bank against the largest single fill demand you expect.
Filtration and air quality
Breathing air quality is a safety issue and it is entirely within your control at the design stage. Specify a proper filtration stack, define a filter change regime by running hours rather than by appearance, and build in the ability to test air quality periodically. Moisture is the dominant enemy in this climate — humidity is high year round, and a filtration system that is adequate in a temperate workshop can be marginal here.
Intake placement — the one that gets people hurt
The compressor air intake must be positioned where it cannot draw engine or generator exhaust, galley extraction, or fumes from any other source, under any combination of wind direction and vessel heading. This sounds obvious and it is violated regularly, usually because the intake was placed for convenience during installation and nobody modelled what happens with a following breeze at anchor. Carbon monoxide in breathing air is a fatal error mode. Place the intake high, well forward of exhaust outlets, and verify it in service under different wind conditions rather than assuming.
Nitrox
If you intend to offer nitrox, decide the method at specification stage. Membrane systems produce enriched air continuously and integrate with the compressor; partial pressure blending requires oxygen storage, oxygen-clean equipment and handling discipline. Both have implications for space, ventilation, crew training and safety procedure. Retrofitting nitrox to a boat built without room for it is expensive and often compromised.
Noise, vibration and location
Compressors are loud and they run at the times guests are on board relaxing. Locate the compartment away from guest cabins, isolate it acoustically, mount the machine on effective vibration isolation, and ventilate it properly — a compressor in a hot, poorly ventilated space runs hotter, works harder and produces worse air. On several boats we have surveyed, the compressor was placed where there happened to be room, directly under a premium cabin.
Deck integration
The compressor is one element of a dive system that also includes tank racks with drainage, fill whips routed so hoses do not cross walkways, rinse tanks with real drainage rather than a bin that stays full of warm water, and a camera table with power and shade. The refit page covers dive deck rework and the specification guide covers the whole system chain.
Frequently asked questions
How big should a liveaboard dive compressor be?
Sized to refill the whole guest load within the surface intervals rather than across the full day, because the schedule compresses fills into short windows. Calculate divers times dives per day times consumed volume, deliver it inside the interval, then add margin for heavy-diving days and larger private cylinders.
Do I need two dive compressors on a liveaboard?
We recommend it. A single failure at sea with no service support ends the trip rather than delaying a dive. The second unit need not be identical — a smaller backup capable of maintaining a reduced schedule is a legitimate arrangement that costs less.
Where should the compressor air intake be placed?
High and well forward of every exhaust outlet, positioned so it cannot draw engine or generator exhaust, galley extraction or other fumes under any combination of wind and heading. Carbon monoxide in breathing air is a fatal error mode, and intake placement is the most common cause.
Talk to the build desk
Send the vessel details or the operating profile you want to run and we will tell you what has to be established before a number means anything. Quotations in USD. Construction, repair, refit and vessel-sale contracts are issued by PT Komodo Galangan Nusantara.