Hi
The prefered method with small boats are to measure from a center line
going from fore to aft. At various stations you tigh a knot and then
measure the distance from the string to the inside hull ---- guess you
can make a temp degree measure so when you measure at a specific
station you also note it's angle , guess you see the point it is and
alway's been the prefered way to measure small open boats no reson for
waterlines as these will show when you digitize the measures.
Do the measures with 10 or 20 deg from a temp angle measure use a
spline instead of a string marks instead of knots and there be a lot
more accurancy.

Best regards
Per Corell
Cyber-Boat
http://groups.yahoo.com/group/Cyber-Boat/