Get one of these from West Marine. Plug it into 12 volts or 120 volts on
board and enjoy cold draft beer right from the mini-keg. I recommend
Heineken. Their mini-kegs have a CO2 cartridge inside so you don't have to
pump them so they don't get air inside to start the skunking process. Good
to the last drop.

http://www.westmarine.com/webapp/wcs/stores/servlet/producte/10001/-1/10001/346889/377%20710/0/Beer%20chiller/Primary%20Search/mode%20matchallpartial/0/0?N=377%20710&Ne=0&Ntt=Beer%20chiller&Ntk=Primary% 20Search&Ntx=mode%20matchallpartial&Nao=0&Ns=0&key word=Beer%20chiller&isLTokenURL=true&storeNum=357& subdeptNum=10852&classNum=10852

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Gregory Hall