Яхты класса IMOCA: Конструкция и особенности

Sailing yacht class

The IMOCA ("Open 60"), is a 60ft (18.288 m) development class monohull sailing yacht governed by the International Monohull Open Class Association (IMOCA). The class pinnacle event are single or two person ocean races, such as the Route du Rhum and the Vendée Globe and this has been intimately linked to design development within the class. The class is recognised by World Sailing.

The class is of "open" design, this means the boat is measurement controlled and therefore designers have freedom within the rules. Several parts including the mast, boom and the canting keel ram and fin are one design for safety reasons. After several severe incidents in the early years of the class a self righting capability was introduced. The boats have to be able to self right themself at any time. Every boat has to prove this capability in a 90 degree or 180 degree test.

Design restrictions include the hull length to be between 59 and 60 feet (18 m) and maximum draft of The length including the bowsprit may not exceed 20.12 m. The max beam is 5,85 m. A maximum of four ballast tanks is allowed. Each of them has a limit in size. First introduced on L'Occitane these are supposed to reduce nose diving, which are lowering the average speed significantly.

The first IMOCAs had a fully open cockpit where winches and ship's wheel(s) were located. With progressing development the work area got more and more protected by a roof open to the back, sometimes also called cave. The ship's wheels where mostly replaced by different versions of tillers as autopilots took over more of the steering. In boats of the 2020 generation the first fully enclosed cockpits appeared, these allow the skippers to stay dry most of the time.

The mast of IMOCAS, which is held in place by several stays is able to turn with the main sail, typically it has about 180 m2. The area of the main sail can be adjusted by lowering it towards the boom, its bottom attachment. The main sail is fully battened. To improve the performance of the mainsail the gap between boom ans hull/cockpit might be closed. Charal 2 implemented this first. In the front most boats have at least four attachment points for headsails. Three on the deck for headsails, one of these stays always on as a staysail to hold the mast in place and one attachment point on the bowsprit that is used for gennaker or spinnaker sails.

Two rudders as well one keel are mandatory. The keel is allowed to be tilted up to 38 degrees to either side. Additionally, two more appendages are allowed. Typically these are either hydrofoils or daggerboards. Both types of appendages are typically capable to be (partially) retracted. The autopilots uses sensors that allow them to take into account sudden variations in apparent wind, speed, load on the foils and sails. Automated obstacle avoidance, whether it is the other ships detected by radar, AIS, or obstacles detected by the OSCAR system, a system to detect unknown floating objects. The data provided by the sensors allow the autopilot to steer the boat in the best wind angle and avoid boat breaking loads.