Offshore Multihull Performance – SYRF COLLABORATION Summer 2016-2017
Over the 2016-2017 sailing season, the Sailing Yacht Research Foundation (SYRF) has worked with a group of multihull owners and representatives to explore the most accurate methodology for predicting the performance of offshore multihulls.
In April 2016, a group of Gunboat multihull owners approached SYRF, seeking a collaborative research relationship, as they sought to quantify gaps between the performance predictions of existing multihull rating rules and observed on-the-water performance.
To collect the data necessary to compare observed and predicted performance, SYRF worked with KND Sailing Performance and Larry Rosenfeld (Team Adventure) to organize a data collection and analysis program during the 2016 Newport, RI summer racing season. The goal of this initial effort was two-fold. First, the SYRF-KND program sought to collect and build a database of multihull data logs for use in validating current and future performance prediction programs; part of this data collection involved assessing the quality and calibration of each boat’s log data. Second, the program aimed to produce an accurate set of performance polars from each boat’s collected data.
These polars were then used to to shadow score regattas using a performance curve scoring (PCS) approach, which the owners believed would better distinguish between the small step changes in sailing conditions (true wind speed, true wind angle) that translate into large step changes in boat performance (i.e. when one boat begins flying a hull in twelve knots of wind while another requires sixteen knots to do the same). Specifically, PCS takes the polars of each boat along with the distance and true wind angle of each leg of the course into account for each race; in theory, race results calculated using the PCS methodology capture the nuanced differences in performance across different boats as the conditions change, reducing the current phenomenon of one boat having a more favorable rating in certain conditions over others.
Encouraged by the results of initial summer 2016 program, the multihull owners formed the Offshore Multihull Association (OMA) in December 2016 to provide a dedicated organization for coordinating the development and structure of offshore multihull racing around the globe. The focus of the OMA is not limited to accurately predicting and capturing the performance of multihulls, with the OMA also working to standardize standard safety protocols for multihull racing worldwide.
The OMA and SYRF have continued to maintain a collaborative research relationship throughout the 2017 season. Most recently, SYRF worked with the OMA to develop a PCS iOS mobile application to better allow racers to understand their current standings against other boats while racing. This PCS application is non-specific to multihulls and can be used in any event that is scored using PCS, including the ORC World Championships; the application will be made available for download through the iTunes application store later this year.