Another place to put a ship's exhaust pipes

No. CO is lighter than air and tends to raise. The problem is insufficient air flow to dissipate CO, or a vortex holding CO near transom, under swim platforms or between pontoons. It is doubly unfortunate that the exhaust ports tend to be located in these vortex zones.

Best to pass through the danger zone quickly. Few people have problems with CO if limited to a breath or two. Major problems occur with prolonged exposure. So don't hangout in the danger zone

 

Manufacturer's claims do not always match up with reality.

 

I didn't say that I believed it. The manufacturer gave the USCG a demonstration of their zero CO generator in 2004. However, other than their instruments we didn't have anything to show it really was zero. We didn't do any independent testing. I still wouldn't try breathing the exhaust.

It is possible though. In 2004 I took my car in to get a new catalytic converter and complete engine tune up before getting my state emissions test. Both the dealer's test and the state's test registered zero CO. Frankly I was astounded. Of course how long that lasted is open to debate.