Where are you going to be hunting from a sailboat?
If you are in California pay attention to this section of the fish and game code. Just because you are not a scull boat don't think the wardens won't nail your ass.
>§507.5. Scull Boats. Migratory game birds may not be taken by a scull boat or similar watercraft while under motorized power. The motor shall be removed from its mountings before any take or approach is attempted.
>This section shall not prohibit shooting migratory game birds from scull boats or similar watercraft with motor attached if beached or anchored; nor shall it prohibit the use of a motor for the sole purpose of picking up dead or injured birds.
To answer your question, buy one of these. Or if you can afford a 55' sailboat buy an over/under with extractors and have no problem keeping your shells around.