Care and consumption of merlot

[HumbleSailor]

I've enjoyed many wines for over 30 years, but am relatively new to drinking merlot. I've heard that it keeps well unrefridgerated, and the one time I tried it chilled, it really stank! At room temperature, however, I've found it very nice. My question relates to my other favorite pastime, sailing. As some of you may be aware, refridgeration on sailboats is an extreme luxury, so having a wine that is drinkable at room temperature is an absolute must... however, it must also remain drinkable for reasonable periods AFTER opening! How long will a decent merlot survive opening at room temperature (that is, any un-consumed portion!)?