Ireland's sailing, boating & maritime magazine

How a Slow Cruising Boat Was Turned Into an IRC Racer

29th June 2020
Yamaha 36 going to windward with Beth Miller helming and Hannah Miller crewing Yamaha 36 going to windward with Beth Miller helming and Hannah Miller crewing

Keith Miller from Wexford transformed his Yamaha 36 from a slow cruising boat into a well-balanced and finely tuned IRC racer

Keith’s Yamaha 36 was doing a race to the Fastnet and back when his backstay parted bending the mast beyond repair. Considering this challenge as an opportunity, and working in partnership with he had a look into improving his Yamaha 36 by creating a better mast and rig set-up. Having read a lot of articles on Afloat about boat “balance” and what can be done to improve a boat’s performance, Keith contacted UK Sailmakers Ireland to see what improvements could be made to his boat.

Getting the Balance & Boat Speed

Keith and UK Sailmakers’ Barry Hayes then reviewed what his previous rig set-up had been and what Keith was willing to do to improve the boat. Given we had to find a mast that would suit what Keith goals were, we got in contact with New Zealand yacht designer Kevin Dibley of Dibley Marine to help us work out the best mast and IRC optimisation design considering the stability and lead (balance) of the boat.

Keith found a second-hand mast form an Oyster 395 which fitted the job perfectly. We then set about analysing the performance and rating that we could get out of the boat with that mast. Working closely with Kevin and crunching a lot of data we came up with a few options.

Testing the reaching set upTesting the reaching set up

Some of the options were: A) a fractional with an overlapping headsail with a smaller main, B) a masthead max non-overlapping headsail with an IRC main, and C) non-overlapping headsail with an oversized main. After scratching our heads and reviewing the data multiple times, we agreed the best plan for giving Keith optimal stability and performance was option B.

Working from there, we did detailed measurements of the boat and rig. Then we built a 3D module of the boat so we could see the aerodynamic drag calculations allowing us to develop the most efficient, aerodynamic sails package possible. All the time we kept in mind the objective of maintaining the stability and lead (balance)in the boat.

Sail design set up and 3D modellingSail design set up and 3D modelling

Keith was focussed on offshore and IRC racing, so we went with X-Drive® Endure sails for offshore performance and reliability. The sails would also have taffeta and enough structural loading for durability with two reefs in his IRC roached main. The headsail was design to be furling with a horizontal battens and an IRC roach. The sail design modelling we did showed that this combination would result in the best durability and performance offshore.

As Covid-19 lifted, and Keith was able to get out sailing, he was itching to see how his plan had come together and see the performance first hand.

The Yamaha 36 Andante sailing off WexfordThe optimised Yamaha 36 sailing off Wexford

Keith updated by email:

Just a quick word to say I was out on Andante at the weekend for the first time with the new rig and sails. We were out in around 10 kts of breeze Saturday and Sunday.

I believe the boat behaved beautifully and was very well balanced. On a reach with the new assym, she was very easy to steer; even when the helm was distracted and went too far upwind, she responded easily to the wheel to get back in control.

Going upwind we had the jib sheet on an inhauler at an angle I didn't think possible. We could steer with slight adjustments to the mainsheet and only about 2 degrees of rudder. I am absolutely delighted and can't wait to be up against some competition. I think we have given this old bus a new lease of life.

I only paid Kevin and UK Sailmakers Ireland €500 for this analysation work to give a new lease of life in this Yamaha 36. She is a totally different boat with excellent performance and stability. I am looking forward to getting out racing.

Yamaha 36 Ireland Rig and SailYamaha 36 Ireland Rig and Sail

UK Sails Summer

About the Loft

UK Sailmakers Ireland brings modern professional sailmaking to Irish Sailing.​ Formerly known as McWilliam Sailmakers; the company was started 50 years ago to bring the latest technology to Irish sailors - we continue this mission today.

Under new leadership in 2018; our loft is dedicated to fulfilling the needs of all Irish sailors. ​As sailmakers, we do not just design sails for boats. We design and build sails for your boat. Our extensive and versatile product line allows us to produce sails to suit your requirements and expectations.   

​As a core loft within the UK Sailmakers Group, we are uniquely placed to draw from a worldwide pool of knowledge and experience - these ties have been recently strengthened with the return of Barry Hayes and Claire Morgan from Hong Kong. ​Barry held a key role in our primary production facility on Hong Kong Island for the past fifteen years. With their return comes a renewed focus on technology R&D on Irish waters.  

​With a wide variety of sailing conditions and an impressive pool of talent, the Irish cruiser racing fleet is the ideal testbed for new technologies.​ 

​As with all things in sailing; the secrets will be closely guarded - but for the first time in decades Irish sailors will be at the forefront of sail technology development.​

Although much has changed; some constants remain. The same great sail and customer service we have provided in the past will continue, as does our commitment and passion for growing the sport of sailing all over the country. 

Barry Hayes

Contact Information:

UK Sailmakers Ireland

Kilnagary Business Park


County Cork

P43 YR22

Republic of Ireland

Tel: +353 21 4831505

Production: +353 (86) 198 0199

Email: Team

About The Author Team

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