Ten Rater spar area measurement - effect on waterline length and displacement

Question Details

When additional spar area is included in the certified rig area, what is the likely effect on measured waterline length and displacement?



The table below shows the result of simple calculations using data for the hull form and additional spar area to determine the required change in waterline length and necessary change in displacement to achieve this. A working spreadhseet will be posted as soon as possible so that actual data can be used to make these estimates.

estimate of change of measured waterline length and ballast weight when adding spar area
length of spar 280 mm
average depth of spar 12 mm
measured area of spar 3360 mm^2
original waterline length 1220 mm
waterline beam 190 mm
slope of bow profile at waterline ending 0.13  
slope of stern profile at waterline ending 0.13  
original permitted sail area 1024590 mm^2
sail area with spar area added 1027950 mm^2
revised required waterline length 1216 mm
change in waterline length 4.0 mm
heave required for this change 0.26 mm
canoe body displacement change 45 cm^3
ballast weight reduction required 49 grams
reduction of volume of lead required 4.4 cm^3
depth of hole drilled in ballast 40 mm
number of holes drilled in ballast 4  
diameter of holes drilled in ballast 5.9 mm
april 23rd 2018