High Modulus has announced its involvement in the production of the Bristolian, a 120-ft Briand-designed lightweight, low-profile sloop. High Modulus supplied the composite structural engineering design and reinforcement materials. She was built at Yachting Developments in New Zealand.
Designed to meet the requirements of the Germanischer Lloyd Rules for Classification and Construction, Special Craft for Yachts Greater than 24m, Bristolian is constructed from E-glass multiaxial and unidirectional fabrics, with PVC foam core. Carbon fiber was used for flange and local reinforcement.The hydraulically controlled lifting keel is housed in an E-glass and carbon fiber keel tower, providing a totally composite casing.
As a monocoque structure of some size in the forward sections and with modern styling requirements, such as large foredeck openings for the sail locker and swimming pool, as well as a fully glazed cabin top, Bristolian required a unique and creative solution from High Modulus. Two particular areas of the boat to which High Modulus applied its experience were the backstay/deck area and the cabin structure.
The backstay/deck join in the aft cockpit is an area of high stress, particularly under race conditions or in extreme weather. As the tender garage was designed with large openings in both the transom and aft cockpit, the engineering challenge was to ensure that the structure remained adequate for the attachment of backstays, and that global vessel strength was sufficient across that area to comfortably manage the anticipated loads.
The cabin top framing was designed with clear spans across the vessel to minimize the visual impact of framing at the windows and within the main saloon area, as well as to maximise headroom. Across the area of the main cabin top, all of the framing is inside the headliner, so High Modulus had to ensure that the size of the structure was minimized, while adequately providing the strength and stiffness required for the likely loads.