News
Things that make it go fast
Published Fri 23 Aug 2024
This series of articles talk about racing under a rating rule, which is not just about what you know. Being an equipment-based sport, sailing is also about what you have. The foils and hull, the rig and sails, all play a role in making your boat go fast and rate well under systems like CBH for trailerable and sportsboats, or IRC and ORC for the bigger boats.
Fred Barrett has been working as a qualified Naval Architect for 30 years and Michael Hutchinson is with Quantum Sails. Both are experts in the field, and they understand yacht racing and what things make it go fast.
What are the principles of producing a fast boat to race under a rating?
FB: The question should be how to improve the performance of the yacht with respect to a rating for a particular sailing venue, regatta or offshore event to suit a multitude of conditions.
To do this is really an exercise to arrive a sweetish spot that doesn’t have any great weakness. For newer design work, we just push the fast and fun button as best we can. Each element of the newer design reflects the refined efficiency of the model. An example may be when designing the right sail area and flying arrangement. A rating improvement maybe made by essentially not over canvassing the design if it’s not required. Same argument with length, displacement, stability, materials choice etc at the beginning of the design process.
For older designs needing a tickle up we look at the mathematics a little differently. The boat performance is in most cases is already defined by its dimensions. Given these limitations exist, it’s a case of the little things that make the improvements on the rating sheet.
MH: Here at Quantum Sails, the first thing is that the owner needs to know what races are important. Are they coastal races, windward leeward, or ocean races? This will affect the sail wardrobe we produce.
On top of knowing the purpose, identifying a boat’s strengths and weakness is important. Once we know that we can tailor a sail plan to optimise the boats performance under IRC or ORC and across all points of sail.
What are the features of your designs that make them fast?
FB: The designs produced often cover a range of different sizes or applications, i.e. sports boats through to Cat 1 offshore racing yachts, and everything in between. Our general theme is “Fast & Fun”, so that may push our designs further towards performance than rating in most instances as they will be relatively light and powered up with significant righting moment.
MH: It begins with the work we do drawing sail plans in a dedicated design office with years of experience. We do that along with custom rig measurement systems and consultation with the owner and crew.
What equipment helps speed but isn’t necessarily rated?
FB: Un-rated equipment, this can be defined by the following.
A. Crew experience and ability with respect to the particular design.
B. Clean and fair race ready underwater preparation, i.e. a clean hull & appendages.
C. Correct Appendage & rudder shape to suit “Balance” and controllability.
D. Correct Mast & rig setup and wind range gear settings.
E. Sail design, Area is rated as defined by measurement. Good sail ‘shape’ is vital.
F. Unnecessary weight onboard. This is a killer.
MH: The crew. Boat preparation, maintenance and the always over looked crew training which should include a theory component.
What do you wish a rating system would change in its approach?
FB: Generally, the IRC and ORCi rating systems offer a way to rate yachts of similar and differing type forms. It’s been working for decades now.
The IRC approach is straight forward requiring a limited set of input data to provide a rating figure. Importantly IRC requires the true weight to be recorded and hence weight for a length heavily plays a part. As do the hull and rig factors that try to capture the overall picture.
The ORC approach takes onboard much more data, hull and appendage data coupled with rig and sail data with righting moment data provided by physical testing. A more mathematical force balance model is used. It plays a crucial role in exploring IRC rating and performance analysis too.
Both rating systems play an important role in yacht racing and the only changes to make is to bring them both more in-line with each other and in particular the way sails can be used and flown and hence rated for.
MH: Nothing really! They are both fine.
What design change, that you have seen over the years, has had the most positive impact on boats’ performance?
FB: Naval architecture and engineering tools have improved to the extent that modern yacht designers have better resources to explore design changes and performance aspects.
In short, utilising modern materials, better tools and understanding of the engineering challenges can be meet with less weight, faster hull shapes, better appendage design and much improved mast and rigging. Sails haven’t escape this either and provide the power source needed with lighter structural weight and refined design shapes that complement the package moving through the water.
Some locked in standards for safety along with sensible stability criteria offshore racing yachts result in really good boats for all levels of racing. Even an AC75 requires some rule restrictions to allow for their sensible usage and longevity for racing.
MH: Since I have been involved in the sport, all aspects from hull design and construction along with modern rigs, deck hardware and electronics have over time improved the enjoyment and performance of sailing.
For information about CBH, IRC and ORC ratings click here.
