The time-varying influence of a sailor’s position is typically neglected in dinghy velocity prediction programs (VPPs). When applied to the assessment of dinghy race performance, the position and motions of the crew become significant but are practically hard to measure as they interact with the motions of the sailboat. As an initial stage in developing a time accurate dinghy VPP this work develops an on-water system capably of measuring the applied hiking moment due to the sailor’s pose and compares this with the resultant dinghy motion. The sailor’s kinematics are captured using a network of inertial motion sensors (IMS) synchronised to a video camera and dinghy motion sensor. The hiking moment is analysed using a ‘stick man’ body representation with the mass and inertial terms associated with the main body segments appropriately scaled for the representative sailor. The accuracy of the pose captured is validated using laboratory based pose measurements. The completed work will provide a platform to model how sailor generated forces interact with the sailboat to affect boat speed. This will be used alongside realistic modelling of the wind and wave loadings to extend an existing time-domain dynamic velocity prediction program (DVPP). The results are demonstrated using a single handed Laser and demonstrate an acceptable level of accuracy.

What follows is based upon our own experience and observations while cruising to the Hudson River and the Great Lakes, up and down the East Coast to Maine and around to the west coast of Florida, and across the Gulf stream to the Bahamas and twice to the Caribbean. We are well aware that we have not learned everything that the cruising life has to teach - and we hope to go back for further lessons. our goal is simply to pass along whatever we have learned that might be of interest to others who may wish to go cruising, and we ask you to read it in that context.

Modern construction techniques allow dinghy hulls to be built well under the minimum weight specified by the class rules. This has lead to a trend, notably in the Olympic dinghy classes, towards hulls with light ends, especially light bows. A number of classes, of which the Finn was the first, have therefore introduced means of measuring the fore and aft weight distribution. Measurements of the pitch and yaw gyradii of Flying Dutchman hulls made at the 1976, 1984 and 1988 Olympic regattas, as well as data for a number of other classes are presented. The various methods used for gyradius measurement are compared, with special emphasis on their precision, accuracy, worldwide reproducibility and the systematic corrections required. Calculations of the contribution of each of the components, including the crew, to the total moment of inertia are presented for Flying Dutchmen.