I installed one that I bought from a RV accessory website. I don't have the make or model but could get it of the docs on the boat if you need the info. There was not a lot of guidance on location in the manual so I picked a convenient place close to the breaker panel. It is a flush mount unit, which I mounted in the fibre glass liner wall under the panel, kind of beside chart table chair, about seat level. It seems to work there, looks good, and is close to the berth that we use.
One note, while working on some bright work I left a brush to dry in the cabin, about an hour later the marina called to say an alarm was sounding on the boat. It seems that the volatile chemicals in the solvent used to clean the brush were enough to set off the alarm as they evaporated?
I don't know if a unit like this would solve your insurance requirements, but it gives me peace of mind while running the diesel heat at night.
You could also look at units made for the general avation industry, if you think stuff for your boat is expensive, wait till you price these babies....they do work.
For aviation grade stuff try, "Aircraft Spruce and Supply"....big web site.
Next time you are boarded by the coast guard, they will be very happy to see a detector.

Do you mean CO2 (carbon dioxide) or CO (carbon monoxide) detector? I bought a marine grade CO detector, which was some $100 or close to it. It failed after about a year and a half or two years. Beyond warranty life. I then bought a couple of household CO detectors. They cost about half the price. Although the warranty doesn't include marine use, they are still working.

[QUOTE=Gorgonshead;13200]Thanks for the reply. Is your unit wired or battery powered?[/QUOTE]

Mine are battery powered. The wired ones run off of 110 DC.

By the way, I have one located on the starboard bulkhead just aft of the hanging closet. I have another one in the rear berth just to the right of the doorway opening up into that berth -- in other words, above the engine compartment in the aft berth.

Glad to see this topic in discussion, I would like to think my mention of it in the last main sheet tech section stimulated to though but, it does not sound like it.

We have a 12v CO monitor on the instrument panel and it works well in that location. I think it is a Xintex (sp) unit. Our smoke detector is just to port of the companionway ladder. It covers the engine and the galley.

I found out when our last smoke detector was malfunctioning, that they have an EXPIRATION DATE and it has about a 10 year life span.

I just went and bought one at the Home Depot -- the PO left a mount that fit most circular household smoke detectors. HD price-matched AMZN; this is the model I got:

[url]http://www.amazon.com/Kidde-KN-COSM-XTR-B-Nighthawk-Combination-Intellig...

Fun fact: most battery-operated smoke detectors are radioactive!