I have one of the Nicro solar/battery powered vents in my foredeck, literally runs all the time, ventilation no problem. For anchoring overnight in the summer when the weather is "hot and sticky," I anchor by the stern, any vagrant breeze keeps the cabin down to ambient. John R. Butler theoldcat@cox.net First M15 was "Joy", '83 #264 Now sail "Rejoyce!", '86 #361