In the beginning of 2008 the Polish yachtsman Konrad Smolen commissioned Ceccarelli Yacht Design for the design of a 33-foot yacht to conform to the ORC GP 33 Class, one of the 3 level classes that the ORC generated, with this rule to replace the old ¾ Ton IOR level class.
The owner of this GP 33 already once had a Ceccarelli design, a nice 27-foot IMS racing boat that gave him a lot of satisfaction winning many races in the Baltic Sea.
This boat was build in 2005 by the yard Stocznia Ustka Sp.z o.o. in Ustka, Poland, and was the sister ship of another important design of Ceccarelli, the previous Sea Winner 42, an IMS cruiser/racer that won many races in Italy and now is sailing in Chile with the name Maestra Nuevo and is also winning now after a new configuration of the appendages for the new ORC rule.
The brief was for a fast and safe boat to race according the new level classes of GP 33 but that could also measure with IRC and ORC. When we received the commission to design this boat the new level class rule of GP 33 was just beginning to take off in Asia, so this may be the first boat in Europe to be launched from beginning of next March 2009.
Since this first boat will be sailed predominantly in Baltic sea, it must be fast both in light to moderate breeze for inshore events and in strong breeze in offshore conditions, so finally we decided to optimize for the prevailing 8 to 16 knot wind range. Accordingly, the VPP data shows speed of 16 knots in 20 KTWS downwind and upwind speed of 7 knots.
The GP 33 rule, defined as a new level class from ORC as a box rule, defines the principal measures of the hull with a maximum length of 10 metres the beam max of 3 metres, fixed rig and sail parameters, fixed max draft for a range of displacement from 2000 - 2100 kg.
The designer must concentrate his research for the best combination of hull shape, rudder and keel configuration, as well as deck definition and a structural plan.
The design work for the correct hull shape started with a full research study on the basic parameters, and from the beginning I decided to go to the maximum beam allowable by the rule and the maximum dynamic length water line and minimum displacement, since the parameter involved in the research was the BWL, prismatic and LCB position.
I decide on a preliminary 3*3 matrix, and a second more refined 3*3 after a preliminary screening with a wider net. Then all the boats were tested with CFD and post processed with a VPP, where I felt I was advanced because we had already done for the same typology research for our GP 26 and GP 42.
A lot of attention in the design process was to the transom area immersed to make the dynamic length as long as possible without being immersed with an increase in drag.
The rule requires scantlings to conform the ABS rule, with the result being a strong but light structure with the use of all carbon fibre and epoxy laminates. All the engineering both of hull and keel was done inside in Ceccarelli Yacht Design.
The fin has a conservative planform area with not too much taper, the idea being that in general smaller fins are faster downwind but could be dangerous at low speeds by not generating enough lift. The fin is made from high resistance steel type Weldox 700, with the fin welded to obtain the correct shape in plan form and section.
According to the hydrodynamic study done, the foils are laminar and support a lead cast and CNC-shaped bulb, with the design being very long and with a low centre of gravity.
The bulb shape also was tested and optimized with the CFD research to obtain the minimum drag versus lower centre of gravity. The rudder build by ISOTOP has the stock and blade build in carbon fibre and a high aspect ratio shape, with the rudder in area was less conservative and is in direction of a small rudder.
The rig builder is King Composites in Argentina, and is a two spreader rig without runners or jumpers. The minimum weight of the mast is not too low so that the choice compromised on being the correct shape for aerodynamic drag and stiffness.
The sail plan dimensions are fixed, but not their shape. If Mr. Smolen chose for his boat to go to North Argentina and he ordered the sails there, they would be designed by Juan Garay who worked with me as designer of the sails of +39 AC Challenge. Balance for the boat was determined using further CFD testing.
The deck lay out is racing oriented, with a wide, large and shallow cockpit for easy movement of the crew. All the deck hardware is from Harken (blocks and winches) and Spinlock for rope clutches, pad eyes, tiller extension. The cabin is designed around the rule with the minimum volume. Below the interior has four berths and are racing oriented.
The boat could be used also in ORC with a preliminary GPH of 560 sec mile.
The same yard that build the Ceccarelli 27 now is building the new Ceccarelli Design CYD 3308. They decided to build a female plug of hull and deck so the boat will be easily replicated in a custom series with an interesting price due to the competitive rate of labour, even though all the materials are of high quality.
From the same mould for next season the yard could build other boats that could be optimized according to the request of the owner in the deck lay out and appendages design.
