As anyone who could tolerate listening to me at the Nationals will know I have been planning a new build.
I did not want to start a forum topic until it was actually under way, which it now is:
I am posting as I know that I will get a lot of helpful hints on lessons others have already learnt,
I suspect that a few will be interested in what we are doing, and hopefully I can inspire others to follow or join this project.
I felt after a year sailing Cherubs that the new boats are markedly quicker than our old slug but also a lot harder to sail.
Whilst this was too our advantage at the nationals it was fairly unique conditions and we wanted a new boat for next year that was closer in speed to the latest boats whilst trying to make it as sail-able as possible.
Almost as soon as we were home we started to try and form these ideas into a design.
The biggest change from most recent Cherubs is to move away from tubular wings to solid wings.
Under the current rules solid wings can be wings and do not have to have a continuous sheer line as per the old rules solid wing boats.
It was felt that solid wings could give a number of advantages:
• A lot of capsizes in the new boats seem to occur at low speed whilst maneuvering. By having solid wings there are more options on where to put your weight.
• The tubular wings often hit waves at speed this is not fast. A wave hitting the clean underside of a solid wing will not drag in the same way; it can positively add righting moment.
• Solid wings can therefore be very slightly lower which all helps with staying upright at very low speeds.
• When they hit the water when nearly stationary they will not sink as fast.
The hull will have small flares that run all the way to the bow and transition smoothly into the wing.
Underwater I wanted a hull shape that was not so different from the current designs but perhaps more orientated to slightly lighter winds.
The racing is closer in lighter winds, giving up time in strong wind races for time in light weather races will result in a net gain in regatta position even if it results in a degrading of the PY.
My hull design therefore has slightly more rocker than most of the new designs, but still very slightly less than Ronin. We had a number of flat out runs side by side with Ronin during the year and they did not seem to be suffering loss of top speed due to excess rocker.
The chine entry angle is much the same as the other modern designs.
The max chine beam is on the 450mm limit 85% aft. Perhaps very slightly further forward than the E6 but with no compromise to the entry angle.
Looking at pictures and from direct observations it appears to me that water only releases at the chine a small percentage of the time. Often the chine is either fully immersed or the release has happened before the chine. This is in contrast to a speed boat or a sailboard where the water truly does release at the chine.
On my hull the chines are therefore slightly higher and less defined. The hull has a tight turn of bilge below the chine with a truly flat bottom panel. The higher chine line probably means that the water line entry angle is actually finer on this design, and the mid ship water line beam may be narrower despite the max chine beam being slightly further forward.
The wetted area should be lower.
Any attached drawings are have only been developed to allow me to see how things are going to work or to allow bits to be made.
A key consideration was to try and find a way of building the boat whilst reaming employed and married before Alex leaves home.
This has yet to be tested.
I will post some more over the next few days and as the project progresses.
Clive