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Hemisphere Sets Sail

superyacht_bmt_nigel_geeBMT Nigel Gee, a subsidiary of the BMT Group, announced its association with Hemisphere, the 44m VPLP design catamaran recently launched from Pendennis Shipyard, that made her world debut at the Monaco Yacht Show. The structural design and engineering of Hemisphere have pushed the boundaries of classification society rules, resulting in the new BV Yacht Rules. Picture courtesy of Pendennis.

BMT worked closely with the vessel’s classification society during the development of a new set of rules for the structural design of vessels of this type and size which subsequently became BV Yacht Rules.

Direct Calculation
BMT Nigel Gee was initially contracted to undertake full structural design and analysis by direct calculation. Definition of global load cases and subsequent analysis was undertaken with extensive use of Finite Element Analysis (FEA) used to analyse both stress and deflection from both global loads and high localised loads at the mast base and rig attachments.

Production Package
BMT delivered a full Class Level Design, ultimately leading to provision of a comprehensive detailed production engineering package. Utilising ARL ShipConstructor for the development of the structure and pipe work systems, BMT provided full CNC cutting files and pipe spools as well as extensive engineering for the yachts complex outfit items.

Weight Guarantees
Part of BMT Nigel Gee’s detailed design contract was to provide weight guarantees for the structure of the yacht. On the completion of each structural unit, weighed weights were returned from the yard and compared with both the early engineering estimates which formed the basis of the guarantee, and the detailed 3D structural production model from which the CNC cut parts were developed. These figures have shown that the yacht’s structure was delivered 6% below the contracted structural weight estimate.

Larger Catamarans
James Roy, Yacht Design Director at BMT Nigel Gee comments: “It has been a real pleasure to work on Hemisphere and the tenacity of her skipper Gavin Bladen is highly commendable. Through this project we have developed further our relationship with the VPLP office and collaborated on even larger ground breaking designs for sailing catamarans up to nearly 80m.” BMT Nigel Gee has already designed and engineered some of the world’s largest and most complex catamarans, including the 80m Sea Fighter for the US Navy, a 55 knots Gas Turbine powered naval vessel.