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100 years of canoe design.
I have done some theoretical comparisons of various designs, using the added mass theory. This theory seems to be used commonly for aiding the design of planing power boats. There are a lot of limitations, listed below, but hull profiles are taken into account to some extent. The two features that are key to the model are the rocker and the beam, and the way these vary along the boat.
The limitations of my model are:
1) deadrise assumed to be zero.
2) clean breakaway of flow at the stern of the boat
3) only forces acting are the dynamic lift and static buoyancy forces.
4) models shapes estimated from very little information, except small line drawings. Hopefully the main features were successfully captured.
5) Hulls modelled using a triple chine design.
6) the driving force assumed to be acting through the centre of mass, so producing no moment constraining the trim angle of the canoe.
7) sailing weights assumed to be he same as for the Nethercot. (except for Mayhem, assumed at 286 lbs)
The results shown for Mayhem are those reported by Steve Clark in about 2012 (Jan) on Dinghy Anarchy. My calculations fitted the data extremely well.
Haze, and Wake are the only canoes which didnot have a chined stern and so it could be expected that they would have more transom drag than the others.
Haze was reportedly the first canoe to plane.
Tritonelle outclassed all the other 'B' class canoes and stopped racing.
Iota ( number 1 on the British numbering system for B and International canoes) was a very simple cheap canoe. designed primarily for ease of building.
Wake was one of the first of the International canoes in the UK. In tests at the National Physics Laboratory they considered her to be a non planing hull!
I would like to have better data for comparison, to see if the theory is really worth using as a design aid for canoes. Any tables of offsets and towing tests would be of extreme value, so I'm looking for people to volunteer some.
I have modified the theory in a very simplistic way to try and account to some extend for deadrise. For chine canoes this can make a big difference, as they will exhibit very small lift close to the bow where the deadrise is approaching 90o Accounting for the driving force not acting through the Centre of gravity will have the effect of scaling the speed axis, although I haven't made estimates of this. For the designs considered, a 10% increase in sailing weight would increase the drag between 3% and 7%.
There are many features which have been incorporated into modern design which improve performance. Gear has improved enormously, so that new boats always outperform old ones. The similarity of Wake and Nethercot, perhaps shows the limitations of the theory but also shows how similar the underwater hulls are.
Finally when I modelled Gaijin, I found drag results well below any of those shown here, due probably to a reduction in the rocker.