Jonathan Happs is to undertake research work concerning sails and rigging as a 3rd year individual project commencing October 2012. A further part of the work, into power configuration, and stability, is the subject of a second proposal by Matthew Slater. It is expected that there will be some cooperation crossover of information between the two, to eliminate redundancy. This suggestion already has the approval of the Boleh Trust, who are keen to involve Ship Science undergraduates in the project. A series of meetings have taken place between executives of the Boleh Trust, Professor P. Wilson and the students to discuss the content and structure of these projects.
Specifically it is suggested that a series of test and a feasibility study be carried out into the unique rigging arrangements on Boleh. At launch, the yacht was fitted with a sloop rig supported by a ‘quadruped’ mast, consisting two hardwood A-frames, stepped onto the deck coaming and meeting at the top, with the main sail setting on a taught luff wire from the peak of this frame. The sail itself was a deep bermudan shape, but with two full-length wooden battens, wish-boned in the fore part of the sail and hinged. In service the wish-bone battens in particular were found to be prone to damage and failure, and replaced with conventional full length battens of bamboo. The Trust are keen to restore Boleh to her original configuration.
It is suggested that a number of materials be investigated and preliminary designs carried out, to ascertain whether the sail batten configuration could be made more viable in the light of modern advances.
An investigation may be carried out into the effect of the four hardwood mast spars on whole ship stability, with the possibility of replacement with composite materials considered.
Boleh has carried a number of different main sail shapes in her life, and the re-designing of the battens may produce a further different design. It is proposed that wind tunnel tests and computer numerical analysis be carried out to ascertain the efficiency and drive available from different configurations, and develop the rig accordingly. Due consideration must also be made to the end use of the ship, the rig must have sufficient complexity to make her an effective sail training vessel, and yet be capable of handling by two or three adult crew in an emergency.
Furthermore, during her life a number of additional sails and spars have been developed to suit certain circumstances, for example balloon and symmetric spinnakers, a square sail and a rafee topsail, and twin whisker poles, all for downwind sailing. There is a therefore the possibility of embellishing the rig analysis and design to include any of these previously existing features if required.
The proposed project represents not only involvement in a fascinating and entirely unique vessel, but the chance to work `in the real world’ for outside clients on a venture with significant financial and emotional investment, and significant relevance to the my intended career.
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Research Paper – Analysis of the Sailing Efficiency
The Junk Yacht Boleh, designed and built by Cmdr. R.A. Kilroy DSC RN in 1949, is currently undergoing a major restoration in Portsmouth, UK.
This is being organised by a charity set up for the purpose, the Boleh Trust. Consequently there is renewed interest in this historic vessel, and particularly in her unique original rig and sail plan. This report provides an assessment of the efficiency and efficacy of this rig through comprehensive wind tunnel testing of a model at 5:31 of full scale, in the University of Southampton’s 7’x5′ wind tunnel.
From the investigations full scale global loads on the rig are presented for a range of wind speeds representing a likely operational envelope for the vessel. Issues with the design of the rig are identified and discussed, and the results are compared against data from literature for alternative rig designs. Provisional optimum sailing attitudes are presented, along with approximate predictions of the speed of the vessel under sail. The results are concluded to be of reasonable accuracy.
Additional investigations of the interaction between multiple lifting surfaces are undertaken using Computational Fluid Dynamics (CFD).