One Off 37

The One Off 37 is a racer-cruiser boat designed for the Estonian yard Ridas Yachts based in Tallinn. The design is based on the one-off built in 2015 by the same yard, indeed the two boats share the deck design and a similar interior layout.

The real difference between the One Off 37 and her predecessor are the hull lines and the appendages which has been modified on the owner request to differentiate the two projects. The new hull presents narrow and vertical V sections at the bow, in order to gain seaworthiness and have a smoother passage through the waves. Between the forward and the midship perpendiculars, the geometry pass from a V to a rounder shape and the bottom becomes flat After the midship, the sections tend to be flat at the centerline but then they go up immediately toward the sheer line to save some wetted area. The deck has been designed for the best ergonomics for racing with a large cockpit and the big wheel located in a central position; the narrow and low coach roof has been designed to guarantee the best movements around the deck and a low aerodynamic resistance. The interiors are all structural, in fact they have been designed to integrate the hull structure and to guarantee the proper longitudinal and transversal stiffness, the materials used have been calculated to guarantee the best weight distribution using the light composite panels at the extremities and solid marine plywood in the central sections of the boat. Hull and deck have been infused using only unidirectional glass fibers in order to obtain the best results in terms of stiffness, weight and costs. The sandwich panels of hull and deck have different pvc characteristics depending on the area where they are located: for instance, at the bow sections, where there are the highest loads due to the slamming, a combination of high density PVC and single skin have been used. All the bulkheads are made of composite materials and taped both to hull and deck. The hull grillage is made by a stainless-steel frame that is entirely over laminate to the hull bottom and the hull structure to ensure the structural continuity and it is capable to carry the high loads from the keel, mast and shrouds. The keel is made of lead with an internal steel structure and it has been enclose between two GRP covers laminated from CNC milled moulds to ensure the perfect hydrodynamic geometry. The boat is fitted with a carbon mast and the sailplan has been developed in collaboration with the north sails designers and optimized with the CFD techniques.


ProjectCossutti Yacht Design
BuilderRidas Yachts - Tallin
LOA11,30 m
Beam3,67 m
Draft2,05 m
Ballast2.000 Kg
Displacement5.500 Kg
Sail Area80 sqm
Mainsail Area44 sqm
Jib Area36 sqm
Spinnaker Area110 sqm