Uncategorized

potemkin

design

potemkin

Designer Yves-Marie Tanton shows his latest work

The Open Class 60 has always been for me, one of the most interesting sailing vessel ever conceived. In her scope, her goal, her pace along with the stamina of her single-handed Driver. So over the years, I have compiled a maximum of data, information and designs to create and expand ongoing R & D for the beast.
The boat is designed with the Vendee Globe in mind. Therefore the total aspect of the design has to be considered, for this Marathon at sea. Ergonomically, simplicity, function ability and speed.

The shape has a few peculiarities.

A "Potemkine" bow allows a fine water entry and the slight reverse curve gives a drier deck of wider proportion to offer a strong base to the permanent bowsprit.
The rest of the boat is built on a chinned platform, wide in beam and almost wider in transom. The chine separates the water, breaks the wetted area downwind while optimizing the placement of water ballast for upwind stability and downwind trim.
The flat Vee’d stern narrows the waterline for a less sticky transom while keeping the buttocks as straight and flat as possible.

The lines are carried towards the bow in a deep and sharp section.
The slight reverse curve given to the sheer line delays the incoming water and reduces the freeboard aft. The deck features the interesting double companionway, separated by a trench. First seen on a Mini Transat 6.5M in 1991. This arrangement permits to centralize the lines coming from the mast and gives cleaner side decks. In my case, I also needed to give a strong support to the boom/vang combination. The two entries offer protection to the helmsman and a better view when steering.

The twin outboard rudders, placed well to the sides are out of the wake exit and are perpendicular to the bottom angle. In case of hitting something, the rudders swing aft, thanks to a “fuse” line built into the system.
The keel is designed to carry all of its lead into the shape of the bulb, for maximum stability. The planform is designed to maximize the aspect ratio available with an optimized sweep back angle. But the most important part has to be the integrity and strength that have to be given to this pendulum keel.
The curved dagger boards are placed as far as outboard as possible in order to take advantages of their higher aspect ratio to producer higher lift with increased stability and less leeway.

The sail plan represents an effort to place the mast as far aft as dictated by balancing the rig with the appendages. The three-diamond system, handles better the column stability for this rotating mast. The Main flat top is in line with what is the norm now. The large fore triangle is divided to accommodate four distribution of the available sail area.