What is the problem?
One of the values we gathered from the towing test was at 1.85m/s, our boat experienced a 3.5N drag. Using this piece of information, i attempt to break down the 3.5N into frictional and residuary resistance using Rf = FSV^n for frictional, subtracting it from 3.5N would yield residuary.
For residuary resistance, i believe i could use
Residuary of actual boat/Residuary of model = (length of boat/length of model)^3
During towing, my model's displacement
would be 330g(weight of the model without anything) + 480g(weight of loaded weights) at a draft
of 3cm, the wetted surface area was 818cm^2. I then estimated the WSA of the actual size boat to be the square of the boat: model ratio which is 20:1.
Ultimately, using FSV^n (actual boat) + (Residuary resistance model x 20^3) sheould give me a close estimate of what the actual size boat resistance would be.However, the frictional resistance i calculat
ed for the model is too small to be true.
L=length of boat=0.54m
P=density of water=1000kg/m^3
F = (P/1000)(0.1392 + (0.2581/2.68+L))
Rf = FSV^n
= 0.219 x 0.0818 x 1.85^1.825
0.055 is way to small...