On December 22, I was preparing the boat (37' Hanse) to take the family out for a few days sail. At the dock, I was running the engine to charge the batteries while I was below working on a few items. Wind was from aft, and the dodger and bimini were up. I thought I was getting seasick at the dock, a bit unsteady on my feet. Then I got nauseous and started throwing up. When the wife arrived, she took me to the emergency room, where they confirmed I had carbon monoxide poisoning. A few hours breathing oxygen and I was sent home, still unsteady on my feet. After a night's sleep, I was fine in the morning.

Needless to say, I am now going to add a CO detector to the boat. What type do the denizens of the board recommend? Reading various materials it appears that home type units, while inexpensive, will result in too many false alarms. How many should I have? One in the main cabin makes sense, but do I really need additional sensor in the V-berth area and quarter berth (both of which can be isolated from the main cabin by doors), given that I don't run the engine while people are sleeping (unless motoring) and don't have a generator or heater on board.

Are there combination CO and propane detectors for marine use?

All advice solicited.

Thanks