John Duffield was born in 1902 at Great Massingham, just outside King's Lynn, where his father had a drapery and grocery shop. The family later moved to another shop at Brancaster Staithe in North Norfolk where he grew up. He joined the Merchant Navy as a cadet in 1919 where he served for a number of years, mainly on the transatlantic route. Back on shore in the 30s, he met up with George Chapman and Bert Stalham, eventually becoming part of the King's Lynn group, although he ‘ploughed a very different furrow’ to the others.

Whereas  George and Bert were concentrating on four-stroke engines at the time, John put all his efforts into developing two-strokes, as has been described in earlier articles. His first boat was carved from a single block of pine with the stepped plywood bottom ‘nailed’ on. He carried on with the King's Lynn tradition of naming boats after wives and girlfriends by calling his boat ‘Lyn’, having married Evelyn (Eve) Emerson in 1936.

All this activity curtailed his modelling severely, but he managed to continue development work on ‘Lyn’s’ engine. With a new magnesium cylinder head to take the newly introduced glow plug and a new induction system with peripheral jet venturi to run on methanol, the original engine was transformed, but it struggled against the radially ported 'Sparky' type motors that began to dominate the 15cc 'B' class.

To overcome this Duffield embarked on two radical pieces of design and engineering, supercharged 15cc two-strokes. Left is what looks like an inline split single with an eccentric vane supercharger. The two glow plugs would suggest a common combustion chamber with both pistons rising and falling together. Short exhaust stubs on both sides serve to confuse the precise internal design. Nothing further is known about this motor.

The other was a far more complex motor with twin disc valves and twin barrel venturi that proved very time consuming to get running successfully, as has been described previously. Eventually the supercharger was discarded, and the engine re-ported to run with a front rotary disc valve. 

Duffield wanted a very lightweight hull to compliment this engine, yet admitted his boat building skills were not up to the task, and so George Chapman built him an exquisite, 33" long hull, using the very minimum of material and the thinnest ply available.

A number of circumstances conspired so that this, the last of the ‘Lyn’ series, was not completed. Finding somewhere to run the boats was becoming more difficult, and John Duffield was experiencing health problems that confined him to a wheel chair, severely curtailed his modelling. He was still able to use his workshop and work at his bench with the aid of a chair on wheels, but racing was out of the question, so his attention turned to other things and the project was abandoned.
John Duffield's lathe now being put to good use by Trevor Chapman

Around 1968, John and Eve visited the St Albans regatta and met John DeMott, a young engineer who had been building and running his own motors and tethered hydros for many years. Through this meeting the two Johns became very good friends and the unfinished boat and engine were eventually passed to John DeMott, who undertook to complete it and run it on behalf of Duffield.

Sadly, John Duffield died in 1971, before the boat was finished, but true to his word, John DeMott managed to get it to run very successfully and continued to run it at regattas until the skeg and propeller were lost, damaging the hull in the process.

John Duffield and George Chapman

Fast-forward to 2007 when John DeMott suggested that the boat be repaired and restored, with the proviso that it was going to be run again. Eve Duffield, having remarried, died in 2001 aged 89, so it was appropriate that the boat named after her should be run again, by another Lynn.

During the 2008 ‘centenary season', Lynn Blowers ran ‘Lyn III’, winning the Peter Lambert Memorial Trophy, and qualifying for the Mears Trophy by completing a run of 1000 yds.

A short item in Marine Models revealed that ‘Dr Hewlett of King's Lynn was building a supercharged two-stroke hydroplane engine’. Not only was this the first mention of Dr Hewlett’s involvement with tethered hydro’s, but also the first hint that there was some exceptional designing and engineering going on in Norfolk. It must still be unique that one group was building four very different supercharged hydroplane engines.

In essence, Dr Hewlett’s motor was two single cylinder motors, bolted either side of an eccentric vane supercharger. Two-strokes are notoriously difficult to supercharge and it seems that the connection of the two cylinders to the ‘blower’ in between proved to be the ‘Achilles heel’ of the design. It is understood that the engine did run, but was mechanically unreliable.

Dr Charles Floyd Hewlett was the only member of the group who was not a ‘Norfolk boy’, as he originated from East Grinstead, yet he continued to be involved with the King's Lynn Club throughout its life, and was certainly in evidence at the Club’s first official MPBA event in 1955, where he presented the prizes.

The regatta took place on a farm pond at Watlington that had become the home water after earlier venues at The Walks in Lynn, Bawsey and Eaton Park in Norwich.

Doctor Hewlett, centre with Colin Stanworth Jnr, on right.