Monday, April 2, 2012
The F.10 is the largest of the Formulae based on Sport Boats concept. Others are the 9M; 8M; 7M, 6M.
They have in commun a basic hull shape developed over years. A chine boat designed around day sailing, with performance on all points of sail. The chines have been adopted for speed, not only on the water, but also in terms of construction where large panels are used throughout, minimizing the time to splice the boat together, making the F.10M. within the reach of a competent Amateur Builder. The hull is one thing, but in order to achieve the goal towards simplicity, a flush deck has been chosen, along with a very large cockpit, all with the intention to achieve speed.
The beam has been limited to 2.75M. (9') for transportation purposes. Also for transportation, a lifting keel on a narrow blade has been adopted. With a deck line fuller at both ends, the boat will have power and limits the amount of water to trample the deck. Where is the bulb? Having complete liberty on the draft issue when the lifting keel is lowered, I replaced the torpedo with an airfoil, with a deeper draft for the same center of gravity given by a shallower bulb. It makes the construction of the apparatus a lot easier, and it is faster through the water.
To control the boat, two rudders have been fitted inside cassettes for removal. They are placed well outside the centerline wave train. In between the two tiller arms is an outboard well, the preferred auxiliary for this type of boat. The penalty of weight would be the consequence of choosing too big an engine.
The cockpit is designed for a racing crew. Properly spaced winches, deck gear and systems; ought to facilitate maneuvers. I favor a forward location for the runners with less length of lines, and less chances of breaking mainsail battens. The side loading on the mast is a question, but so his the pull sideways of the sprit sail, high on the mast. Also, the location of the outboard engine in the stern might interfere with the runners.
The main spar should be made of composites of course. More budget minded customers have recourse to aluminum. I envision a single set of spreaders for simplicity, a single diamond rig with addition of diagonals and main shrouds, to equalize mast compression. In adopting this sail plan, with a square head mainsail, the mast can be cut by one meter for a given sail area, saving in cost and weight. The jib is about half the zize of the mainsail, withile the spritsail is close to three times the area of the later.
The Formulae provides spirited sailing performance, sported on a logical hull platform. The concept is valid up and down the scale, only limited by individual choices.
Length on Deck. 10M. 32.8'
Beam on Deck 2.75M. 9.0'
Draft Keel up. 1.2M. 4.0'
Draft keel Down. 2.67M. 8.75'
Displacement. 2T 4400Lbs.
Sail Plan. 1. 12.45M. 40.83' J 3.28M. 10.75'
P. 12.45M. 40.83' E 4.72M. 15.48'
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