Welcome to the OK coral

The Daily Sail
Robert Deaves

Expert sailor Robert Deaves updates us on the OK singlehanded dinghy
The OK Dinghy is one of those classic designs that has survived the test of time and remains to this day one of the most widespread international dinghies with a loyal worldwide following. This popular 4.5m long singlehander is sailed in over twenty countries across the world, and has inspired generation after generation to get involved in international sailing.
The class has recently seen an upsurge in interest following the introduction of carbon masts in 2003 and a gradual modernisation of the rules to allow new materials to be used. Recent world championships have been held at venues including New Zealand and Goa; last year's world championship at Parkstone YC in the UK was oversubscribed with a maximum field of 81 boats participating. International sailing is one of the OK's strongest assets with large fleets in New Zealand, Australia, Germany, Sweden, Denmark, Poland and India as well as Great Britain. Good turnouts at the Spring Cup in Medemblik, Kiel Week, Warnemunde Week and others, keep attracting boats from all over Europe and provides a good indicator of performance at the world championships.

In just over 18 months, the OK Dinghy will become 50 years old. Like the Optimist, the OK Dinghy was born out of a philosophy to encourage amateur sailors to build their own boats and 'just get out on the water' at a time after World War II when sailing was gradually becoming less of a rich man's sport.

One man linked these two successful classes together. A close friend of the great Paul Elvstrøm, Axel Damgaard Olsen was a Danish architect living in Seattle, USA. On a visit home to Denmark in 1954 he brought with him plans for the now world famous Optimist, and as far as that class was concerned, the rest is history. He also inspired his friend, the yacht designer and boatbuilder Knud Olsen to transfer an idea from his imagination onto paper for a fast and light, hard-chined planning dinghy with a simple unstayed rig. Knud drew the plans for the OK Dinghy and in 1957 the first OK hit the water - they immediately knew they were onto a winner.

It was simply 'okay', and with Knud's reversed initials, the boat found popularity worldwide and introduced thousands of people to sailing who would never have had the opportunity without Knud's design.

Amateur principals

The principal idea behind Knud's design and Axel's imagination was people having fun together on the water. Tolerances were close but flexible enough for amateur builders. Axel encouraged builders to keep everything uncomplicated and fun. The simple plywood construction lends itself perfectly to home builders and although early fast boats were generally plywood, enthusiasts also experimented with fibreglass.

Half a century after these opening scenes, the class has spread to virtually every corner of the globe with over 15,000 boats having been built worldwide. The same way of thinking still holds true of the class today. Everyone has their own idea of what is the best design, but in truth a wide range of very different hull shapes have won the world championship in recent years. No hull, rig or trend tends to dominate for very long.

The phenomenal rise to fame of the OK occurred largely as a result of intensive Scandinavian interest, a part of the world that dominated the OK racing scene at International level for many of the early years of the class. This all happened in the days before the Laser was conceived and very much filled a niche in the market for sailors without the machismo or finance to campaign a Finn.

UK success

Two years after it was first launched, the OK was introduced into the UK by Richard Creagh-Osborne and a class structure was soon established. In these early days, over 100 boats were being built each year and sail numbers in the UK are now past the 2100 mark.

However, it was 47 years before Britain could produce a World Champion. It was a standing joke within the class that no British sailor was good enough to win the worlds - the best they could achieve was second or third. However the ghosts were finally put to rest in 2004 at Parkstone Yacht Club when Jim Hunt - who had turned his hand to OK sailing just a few years previously - dominated the experienced field to win by a large margin.

Britain is now looking for its second title, but with Hunt moving off into the Finn class, the mantle has been left with Nick Craig - runner up in 2004 - offering the best possible chance. As highlighted in a recent thedailysail.com interview, Craig has come, oh-so-close, on a number of occasions, but the title has continued to elude him. Also having moved into the Finn class, "just for fun" he says, Craig has two chances over the next nine months.

The first will be in Denmark at Skælskør Sailing Club, located about 70 miles to the west of Copenhagen, where Craig is leading a seven strong British team in July. The second will be at Belmont 16ft Sailing Club on Lake Macquarie, about 100 miles north of Sydney in Australia in February 2006. The class world championship is traditionally in Australia or New Zealand on a four year rotating basis. In these years the class also holds a European Championship. In 2006 this is being sailed in Loctudy in north-west France. Thus each European Champion has the honour of holding the title for four years; the current champion is Bart Bomans from Belgium.


The class has always proved popular in Europe and the antipodes, with some growth in the Far East and the occasional flourish in America and Canada. The OK seemed to fit nicely into a 'niche' between the starter boats and the Finn, and for this reason, the OK developed a reputation as a Finn training boat, especially in Nordic and eastern European countries. In fact many of the top Finn sailors of the past cut their teeth in the OK.

Interestingly, the OK has followed a similar technical path to the Finn, both classes introducing fast fibreglass hulls, metal masts and Dacron sails around the same time. However, with the Finn going to carbon masts in 1993, it took another 11 years before the OK class was willing to take this step - albeit with some trepidation - but the results so far have proved encouraging.

The OK has always tried to foster amateur level sailing and for this reason there is a camaraderie among the sailors that remains friendly while also being very competitive. The simplicity of the building and measuring process plays a large part in this, and while it remains very simple to sail, it offers a challenge both in terms of evolving designs and perfecting sailing technique.

Early boats sported a thick wooden mast with a wedge to hold the boom down. A hole in the mast for the boom was seen as simpler and cheaper than a gooseneck. These early rigs were partly responsible for some of the myths surrounding the OK, when low booms were the norm and decapitation an everyday hazard of sailing the boat in strong winds. Today, goosenecks and powerful vangs allow sufficient adjustability to sail upwind with no vang tension at all. The boom is normally strapped to the deck upwind in any breeze, but on releasing the mainsheet the boom will clear all but the most colossal of helms.

The class today

No single hull design or construction method has ever dominated class racing, although in the early years, the Scandinavians seemed to get it right most of the time. Wooden, composite and glass boats, (some new, some over 10 years old), have all finished in the top positions in recent World Championships. Even though hull tolerances are greater than some classes, it doesn't seem to make much difference to the OK, as long as the basics are correct.

Over the years builders have tried to exploit the rules to the limit to find that magic rocket ship. Some boats are even built straight down the middle and prove equally fast on the water. The variations in speed are in the way the boat is sailed and in getting the most out of the rig, with its unstayed rotating mast.

In the UK the Don O'Donnell OK (or variations and copies of it) dominated the results from the 1970s until the mid-1980s when some fuller bowed boats were introduced. These proved fast in the right hands (usually the larger sailor), the earlier ones being built by Bob Hoare (of FD fame), the later ones being imported from Hein in Germany. The mast that was universally used in the days before carbon was a Needlespar, matched with a Batt or Ullman sail and the occasional Green sail from Denmark.

All change

In 1995 everything started to change. Following the World Championship at Felixstowe Ferry, development commenced on an all-glass hull. Composite OKs are normally favoured because plywood is light and strong, and the problem with building glass decked OKs is keeping the weight down sufficiently, whilst making it strong enough to cope with the enormous strains that the unsupported mast puts on the foredeck. Previous all-glass OKs built in Europe never seemed to have that edge required to win.

Rushworth Racing Dinghies had been producing composite hulls for five years, and these had won many UK events. The hull shape was taken from a standard Parker hull, which itself came from an O'Donnell wooden hull. Even though this particular hull shape has been around since the mid-1970s it is still quick over the water even today.

The existing mould was modified - the prototype was duly launched in the spring of 1996 and won its first race. The major difference between the Rushworth OK and previous hulls was in combining the decks and the bulkheads in one piece. The sidedecks were moulded separately before being fitted to the hull. This all added strength to the deck area without adding weight.

Over the next 7-8 years Rushworth boats achieved success across the board, winning most UK Nationals as well as many International events. Finally in 2003, in the hands of Indian sailor Nitin Mongia, a Rushworth hull won the world championship held in Goa, India. In 2004 at the World Championship at Parkstone, Rushworth hulls sailed by Hunt, Craig and Mongia filled the top three positions. The masts were all UK made by Seldon and the sails were UK made Norths. In a class where the British had always struggled to make the grade here was the proof that they finally had the sailors and the technology to take on the world - and win.

Rig development

The new look OK really needed a new mast to replace the outdated Needlespar aluminium mast. And after nearly a decade of heated discussion and debate the class finally introduced carbon masts in 2003, just after the Goa worlds. The possibility of wing masts - which caused an arms race in the Finn class - was reduced by making the fore/aft dimension proportional to the sideways dimension at the same height. The change to carbon masts was very much an unknown quantity, but so far this strategy has succeeded with five mast builders across the world producing some high quality and consistent products. In the UK, the most popular is the Seldon mast - used by both Hunt and Craig last year. The Seldon mast is a simple solution with two CNC filament wound tapered round sections joined together with a separate track. Superspars tried a similar version which has yet to be proven. JP Williams continued the amateur construction philosophy of the class by building a nice one-piece mast at home and this has been used to good effect by some British sailors.

Other UK sailors have opted to go overseas in search of speed. Both the Ceiligh mast from The Netherlands and the C-Tech from New Zealand are highly engineered good looking tear-drop shaped masts, although the Ceiligh is the most expensive on the market at the current time. The Danish sailors have also developed their own one piece masts, but again these have not been proven internationally.

Although a grandfathering policy was built into the mast rule so as not to outclass existing aluminium masts overnight, the majority of the fleet switched to carbon within a year and aluminium masts are now rarely seen on the circuit. The flexibility of constructing in carbon also allows a greater tailoring of mast stiffness to body weight and sailing style, something that was very much hit and miss with aluminium. Computer controlled construction techniques remove the human factor so manufacturers can reliably reproduce consistent and accurate mast bends again and again. This in turn means you get the mast you want first time and allows a wider range of body weights to sail the boat competitively.

After an unsuccessful attempt at building OK sails in the 1980s, North Sails came back in 2000 with a new world beating model, based on their Olympic winning Finn designs. Developed by North's Paul Hobson in conjunction with Craig, Hunt, and Ian Howarth of Seldon, North Sails have virtually dominated the UK market for the past five years. Overseas, WB Sails of Finland have produced a large open leeched sail that won the 2003 Europeans while Greg Wilcox won the 2002 worlds in New Zealand with his Port Nicholson Sail, made in Wellington, New Zealand. Other popular lofts include North (New Zealand) and Pinnell & Bax. The Germans and Danes still mainly use the Danish Green sails, among a host of sails from smaller lofts. And will the OK Dinghy follow other classes and adopt hard sails made from Mylar and Kevlar? There have been a few experimental sails, but the class is sticking with Dacron for the time being.

The future

Having achieving the pinnacle of OK sailing and having built some 65 OKs over the years, Rushworth is moving on and now the OK moulds lie unused in his Christchurch workshop. In the past five years, the UK has produced the best hulls, sails and masts in the world, and the class association is now actively looking for a builder to take over the moulds and continue the line of competitive OKs started by Rushworth.

Craig, on the other hand, is now campaigning a New Zealand hull with a Dutch mast and a UK North sail, looking for that extra fraction of a knot that will help him to achieve his ambition to lift the OK Dinghy World Championship title later this year in Denmark. Watch this space.

For more information see the international class website or British website.

The Daily Sail
Robert Deaves