The key to cabin and bilge ventilation is laminar airflow, facilitated by an
open cabin door with proper fore vents. Adding a dodger to the cockpit has
shown to increase carbon monoxide levels in both the cabin and cockpit. The
use of a filter manometer has shown that the normal cabin cockpit pressure
differential of 1-2" of water drops drasctically to about .050 inches and
may go negative. The CO can arise from either engine or stove use. It is
highly recommended that a CO monitor be in place when a dodger is in use.
Also seals around the engine housing should be checked and the bilge blower
run for at least double the normal time before firing up the engine. The
dodger is also capable of trapping the escaping gases from an external
propane bottle and, legally, using a dodger puts the propane bottle inside
the cabin. Insurance companies have used this tactic to get out of claims.
Make sure the gas locker is outside the cockpit and the low point of gas
travel does not enter into the cockpit and then into the cabin.

BC