With the help of info that people shared with me in this newsgroup, I
have found that the _smallest_ boat for 4 persons in a boat is 18-ft,
and I have already got it in my driveway

Actually, it is a 17-1/2-ft center console. Seem like all the
manufacturers like to round up the number.

A 16-1/2-ft center console (manufacturer called it a 17-ft boat) is
just too small for 4 persons. I didn't know that one foot difference
could make such a large impact until I stood on top of the 16-1/2-ft
boat and looked around. I estimate that the 16-1/2-ft is probably good
for 3 adults.

Thanks again for the info that I have received here.

Jay Chan