For Mutt71, I can not send you any message, so:
I have posted a procedure with pics about how to make a simple sampan boat:
http://www.warbird-photos.com/gpxd/view ... =9&t=37056
Hope it will give you some inspiration.
Now, as you had also interest for houses like the ones I made for my small oriental harbor diorama (the most vietnamese was made with old beach straw mat), here are pics from the inside, that shows the pine wood stick frame, probably exactly like the real houses are made:

Note that the small sampan in front of the house is made following exactly the same procedure as shown on the topic in the custom&mods section, just the size and proportions are different. It floats well, even with 2 1/18 figures.
The concrete house is really made with concrete, poured on a wire mesh from a hen house in successive molds made for each façades... the final result is very heavy, I used it for a boarder house with a different roof. My straw house is easier to do...
