When I cruised in Boating Magazine's Scout 242 Abaco to Martha's Vineyard one weekend, I was glad I had a Cruisair Carry-On portable air-conditioner ready for testing. The temperature was a balmy 90 degrees, and every amenity pays exponential dividends in comfort.

The Carry-On installs by resting on the foredeck; its vent and control panel protrude through an open deck hatch. A skirt and battens are provided, which makes it easy to seal off the hatch from bugs and allows the unit to fit most hatches. The unit weighs about 50 pounds and is fitted with handles to ease positioning. A bubble level is built-in-we used some scrap wood to shim the unit so it was level, which is necessary for proper operation. It requires a 15-amp powercord, so you'll need to purchase an adapter for about $50 to connect to typical 30-amp shorepower. It chilled the Scout's cuddy to a dry, comfortable temperature and made 64 dB-A. Price: $970.

Contact Dometic at 804/746-1313, www.tmenviro.com.