Our friend Klaus Hafner (make sure and check out his aluminum river boat build) pointed out a book that might be of interest:
Bruce, found and already read this book. The Warm Dry Boat, by Roger McAfee Some very good informations to deal with venting and heating boats, discussing different techniques and efforts. Maybe you are interested to offer, was not possible to get it from Amazon, just a used one for more 100$ I paid incl shipping to Frankfurt ca. 50$
This is the contact Navigator Stove Works LLC [firstname.lastname@example.org]
Navigator Stove Works LLC
509 Double Hill Road
98245 USA Ph. 360 376 5161
The Navigator Stove Works, Inc. web site referenced looks quite interesting and detailed. Keeping a boat warm and dry always seems to be a challenge. New/good ideas for maintaining your living spaces is something to keep abreast of.