Article by Capt. Steve Katz
Chill out
These last few weeks of heat may have kept many of us on land, near the cool breeze of an air conditioner. If you have a boat and wished it had air conditioning, installing a system may be easier and less expensive than you think. Even the smallest boats can have an air conditioner to help keep you cooler and comfortable while on the water. The cool air can even be shared between the cabin and the helm to provide a refreshing blast of cold air on those hot days.
Large sport fish boats have a complex system of engineered air conditioners, chillers and refrigeration systems to keep the people, provisions, bait and the catch at the proper temperature. Names like Dometic, MarineAir and Cruisair have dominated the marine air conditioning market for years. These companies are always developing new products based on customer needs and design trends.
Some boats have a marine air-conditioning system that is referred to as a split system, which has the compressor and condenser in the engine room and the evaporator and fan in the cabin. Another style of system is the compact, all-in–one system that has the compressor, condenser, evaporator and fan all in one package, often installed in the living area under a bunk, settee or in a locker. These compact systems are available in many sizes, but also are easily adapted to the smallest of boats.
A marine generator making 120v or 240v of electricity is mandatory to properly run an air conditioning for an extended period of time. In the case of a smaller boat without a generator, a compact air conditioning system can usually operate as long as the engine is running and providing large amounts of electricity through its alternator to the batteries and/or inverter.
If you are shopping for a small marine air conditioning system, going with a standard 120v system connected to an inverter is a better choice than the special 12v systems since those components are not as popular and often more expensive to purchase and repair.
To determine if your boat has the electrical capacity to run one of these small units, it is first recommended to install additional batteries and use a dedicated house bank battery. Just in case the air conducting drains your battery, you want to be sure the engine batteries remain charged, allowing you to start and run your engine independently of the air conditioning system. For example, a Climma Compact 4.2 will draw, on average, between 35 and 40 amps at 12v DC, including the water pump and inverter loss. Compressor starting loads are not significant, and an inverter of at least 1,000 watts can start and run the system according to the manufacturer.
Marine air conditioning systems require seawater for cooling of the refrigerant. The seawater system consists of a thru-hull fitting, seacock, strainer, pump and overboard discharge fitting. Dometic recommends a centrifugal seawater pump for efficient, quiet operation and a long life. Centrifugal pumps are not self-priming and must be mounted below the waterline.
A complete system requires the control/switch assembly, the seawater cooling system and the air distribution system along with the actual compact system. While some of the small systems are designed and marketed to the do-it-yourself boat owner, many other systems require a trained technician to proper install and warranty the system. A quick check at popular retailers shows prices of a basic do-it-yourself system beginning at $1,200 for a 5,000 BTU/hr air conditioning system that is also a reverse cycle heater.
If you have a fish box or drink box to cool, instead of using ice, you could install a chill plate system, which uses a refrigeration compressor and custom off-the-shelf chill plates mounted into the fish box. These systems are often custom designed, but there are off-the-shelf kits that allow you to select the system components that fit your needs. Some of these chill plate compressor systems can be air cooled like the popular Dometic KRA system, eliminating the cost and complications of a seawater cooled condenser. For example, one company offers a small, 12V DC air cooled compressor and two chill plates for $1,200.
If you are tired of your drinks getting warm after you open them, Dometic has designed a cup holder with built-in refrigeration, called the Eskimo Cup. This unit fits into a space not much larger than a standard cup holder and only requires a small 12v power feed. It functions as a cup holder but maintains, or reduces, the temperature of your drink. A nice do it yourself project under $200.
Whether its cooling for people, your catch of the day or your beverages, there are many options for all types of boats and budgets.
Captain Steve Katz is the owner of Steve’s Marine Service and holds NMEA, AMEI and NMEA2000 certificates along with ABYC Master Technician certification and factory training from many manufacturers.
