A New Era – Project 21


Through 2007, the new hydroplane ’21’ was raced by Craig Speller, but it was also a test model for Project 21. After completion of development, ’21’ was used to create a set of moulds.




The first two hulls completed production and were prepared for the first races at Stewartby during the Easter Weekend. The weather conditions, with high winds and snow shows prevented the hydroplanes from racing.

Project 21 is much more than a new hydroplane hull produced from composites. The story will unfold during 2008.

Final Development Stage for ’21’


Photo: Trevor Chatters

After the World Championships development work on ’21’ continued, this has involved reducing the overall length of the hull by some 10″ [250mm] and minor adjustments. The end result has been greatly improved acceleration, better handling and much faster lap times overall. The Last UK National race of the 2007 season saw the boat dominate the event with 4 wins from 4 starts, this even though we were still experimenting with engine settings and props. The picture shows Craig putting the boat through some more buoy turns at the Bedford event.

’21’ World Championship Configuration


During practice for the World Championship, the fairing ahead of the the engine was providing too much down thrust

When ’21’ entered the water for the first time, it was known that testing would show a need for modification and that there was very little test time available before the World Championship.

The new hydroplane incorporated a number of new ideas which had not been tested before on other hulls.

In the first outings, the hydroplane proved to have a high speed potential but modifications and tuning would be required to exploit that potential.

Initially the weakness was a result of the craft coming too far out of the water which cut the supply of cooling water to the engine, raising the bore temperature to critical levels.

Various settings were tried for the engine in an attempt to resolve the overheating problem but without losing thrust in other sections of the speed range.

It was an advantage that the Stage 2 competition for the British Nationals took place in foul weather with continuous rain and low temperatures. Even so, practice laps saw the engine ‘nip’, requiring a strip down and re-assembly, but it did allow Craig to achieve the fastest practice lap and achieve pole position for the heats.

A combination of some very smart work on rebuilding the engine, and the unusually low temperatures allowed Craig to push the hydroplane and dominate all heats for Stage 2.

It was clear that there was a problem to solve in very little test time. Video of ’21’ showed that the prop was not making adequate contact coming down the straights. Lowering the engine on the transom improved running on the straights but placed the prop too low in the water on the turns.

Finally it was decided to try a fairing ahead of the engine and adjustable aerofoil trim tabs. The fairing seemed to help resolve the problems, although the aerofoils were less successful, the main difficulty being in getting the setting right and locking them in position before the hydroplane raced.

The result of these trials was the configuration used for the World Championship. Unfortunately, the fairing produced too much down thrust in the conditions applying at Oulton Broad. Craig had to struggle to get adequate performance. Adjustment of the engine position between laps took the performance up and, by the final lap, which was terminated early, ’21’ was showing a significant improvement, if too late for Craig in the Championship.

Keeping Cool


The last weeks have been hectic for Craig and Team-21. With the World Championship only a few weeks away, the real race is to get as much water time as possible to make the final adjustments, and for Craig to find all of the little quirks of his new craft. In Britain there is a serious shortage of suitable stretches of water for testing hydroplanes and for racing. The situation has been made more difficult this year because the very wet recent weather has also reduced light and, with it, the length of time each day when a hydroplane can operate safely.


The ’21’ has proved to be exceptionally fast and very robust. Few modifications have had to be made and it is now exactly on the correct weight for craft and driver. The engine has presented some challenges and Craig has had to return to the pits on several occasions for the tuners to strip and check the engine.

The difficulty has been a combination of the Class requirements that the engine be a standard engine, and the high performance of the craft. This has resulted in the engine cooling water intake being out of the water too long, leading to overheating problems.

When this occurred during the British National Championship Stage 2, at the end of May, Craig had turned in the fastest lap during practice and then had to return for engine checks when he felt the engine ‘nip’. A ‘nip’ is usually the precursor of an engine seizing up. It can be a result of fine grit getting inside the cylinders, but it is often an indicator of serious overheating.

His engine tuners had to strip down the engine and polish the cylinder bores. They decided not to fit the spare pistons because, on careful examination, the existing pistons only needed a thorough clean before reassembling the engine. Doing this in the open during a downpour was a challenge but the result was so good that Craig dominated the heats with a clear win for the day.

Further intensive testing and adjustments seem to have solved the problems. The trick is to mount the engine low enough that the cooling water intake is immersed often enough to keep the engine within its temperature tolerances at high speed, but to keep the propeller high enough to maintain the optimum thrust line at lower speeds and particularly at the critical cold start at the beginning of a race.

The OSY 400 Class rules are very strict and traditional. In particular, they prohibit the use of any parts, other than steering, that are able to move during a race. If the rules were to permit moving parts, much greater performance would be possible by introducing variable geometry for the engine and for ram-air intakes in the hull, all under control of a computer. Other hydroplane classes do permit some variable engine geometry because the engine has to be trimmed to suit the speed range.


In any sport, where technology is directly involved, it is always difficult to steer a course between fairness and design improvements and maintain safety standards. The logical development of the hydroplane is the hovercraft and the design origins of the hovercraft were in attempts to create a layer of bubbles along a boat hull to reduce friction. The first hovercraft simply used a large fan to create a cushion of air under the craft and maintain it through the complete speed range. The next refinement was to add a rubber skirt to reduce the effort required to maintain the air cushion. A hydroplane builds up a cushion of air as it gains speed but loses the cushion when the speed drops and the craft banks into a turn. The air cushion also fails to keep the craft clear of the water at all times during a straight high speed leg of a circuit because there is little boundary control over the air cushion. One method of improving the performance of the air cushion would be to use variable geometry air scoops to inject additional volumes of air, particularly during lower speeds and during turns. To make this passive augmentation function reliably, the intakes would have to be constantly adjusted individually and only a computer would be able to do that fast enough.

Nearly There


Working up a new hydroplane takes time and one challenge is finding enough water time to get everything set up to optimum and for the driver to fully understand the new craft. A month after first launch of the new ’21’, and its trailer is now supporting the Team-21 colours and carrying the sponsors’ logos.


’21’ has now collected a selection of company logos but still looks like a new boat.


Not only have trailer and hydroplane acquired signage and colours, but the team members are now in their new team clothing.


A smart team and craft don’t make for a winner directly, but a smart team tends to make for a smart start which can be the difference between winning and losing. Team-21 always start the day with a race start even when ’21’ is just heading rom the launching point round to the club pontoons

Preparation to race


This F4 Class hydroplane is towed on a typical open boat trailer but the tow vehicle provides some of the comforts of home for its crew.

The OSY 400 class are very easy to trail. Everyone has a different idea of how to do it. The most popular trailer is an open boat trailer which can be run down a slipway to launch the hydroplane.

Of course that means that the tow vehicle has to carry the spares and tools and the hydroplane is exposed to whatever conditions are met on the road to the next competition


’91’ has a neat arrangement. The road trailer serves as a cargo box and support for a launching dolley in which the hydroplane sits, but it still exposes the craft to all the dirt and debris when being towed to the race circuit.


’21’ has a fully enclosed trailer. This calls for a little manpower, sliding her out of the trailer, but she is protected from road debris and curious fingers. This was the first time the new trailer was used, with trailer and boat still being largely unstickered.

Team-21 have chosen to use a fully enclosed trailer and to demount some of the equipment for transit. This adds some time to ‘pits’ preparation before launching, but it reduces risks in transit.


Without fuel and engine, ’21’ is light enough to be handled comfortably by two people. This view shows just how tightly OSY 400 hydroplanes fit their drivers.


’21’ is now out of the trailer and positioned ready for the outboard motor to be fitted onto the drive leg. The drive leg has been left mounted in transit with the stearing cables attached and tensioned. The step cut-outs seen in the cockpit floor provide a choice of toe hold positions for Craig.


The motor has been removed from its transit box and is about to be placed onto the drive leg.


In position, the motor is then bolted down ready for testing.


The motor fires first time. The top-puller needs two people to hold the hydroplane steady as the engine is test fired and run up.


An OSY 400 driver of the future? The Juniors race in deep V monohulls and launching from the dolly with driver aboard is a preferred method.


With ’21’ ready for launching and the race, the extra weight requires three people to carefully carry her to the pontoon.


With ’21’ in the water, Craig has stepped aboard and is settling into the prone position.


With the engine fully tested, it starts very easily and the hydroplane is immediately underway.

’21’ Craig Speller’s OSY400 Hydroplane


’21’ taking shape. The aerofoil shape of the hull is clearly visible before the plywood skin is applied. The craft is built to fit the driver and the combined weight of driver and craft has to meet a minimum figure for World Championships.

During his career in hydroplane racing, Craig has used a number of hydroplanes. ’21’ has been built by Newsons Boatbuilders specifically for the 2007 OSY400 World Hydroplane Championship.


’21’ arriving at Oulton Broad for its first trial on water. This was a short trip from Newsons Boatbuilders, using a temporary trailer.

Once the construction was complete, ’21’ had to be trialled and the first launching was at Oulton Broad on April 26, the second evening meeting of 2007 for the LOBMBC at Oulton Broad. Hydroplanes have changed little over the years and trace their ancestory back to the early aviation industry, before 1907, when the first craft were built to test the hydrodynamic performance of the early seaplane designs. ’21’ is a major advance that is unique and includes the use of nanotechnology.


Setting the engine up is a very important task. A new craft will have some unforeseen characteristics and trials show how the engine position must be fined tuned. Once the position has been fixed, the engine itself is adjusted for maximum safe power output. Although a driver can lose a race, engineering can allow him or her to win.

During the weeks leading up to the 2007 OSY400 World Hydroplane Championship, Team-21 will have to work very hard setting the craft up. For the first launching, the main attention was to the engine. The challenge is that time is limited. Every opportunity has to be taken to ensure that the behaviour of the craft is fully understood, any necessary modifications are made and re-tested, and both craft and engine are fully tuned for the World Championship.


A racing start for the first trip of ’21’, close to the conditions for a Championship start.

During this frantic period of testing, Craig will mostly be racing under club rules which allow the mixing of Koenig 500 and OSY400 craft together and employ a handicap system with the most experienced drivers starting from the back of the field. That means that Craig will have to fight his way up through the disturbed water from less experienced drivers. For the World Championship, only OSY400 craft will race each other and the start includes engine start to the command of a traffic light system with the fastest away attempting to hold pole position in the clear water ahead of the following competitors.