Thornycroft's Scolopendra is back home in the UK 2015
Thornycroft & Co were established builders of steam powered commercial and military road vehicles, at Basingstoke; and steel torpedo boats for various foreign navies, at their Chiswick Yard on the Thames. Back in 1873, John Thornycroft produced one of the first motor torpedo boats, the steam powered, 458 hp, Gitana and she achieved 24 mph. Four years later, in 1877, Thornycroft took out several patents for skimming semi-displacement hulls, and for a revolutionary semi-submerged propeller.
Copyright © 2016 *Graham Mackereth Dukes Meadows Park all rights reserved
Harmsworth Trophy and the Yachtsman's Cup (Handicap) 
The photo of the nameplates from the Scolopendra were supplied by Bruce Devine from Montreal Canada, who owned the boat that goes with those plates, which he was restoring until the change of ownership*
In 1903 John Thornycroft entered the first running of the Harmsworth Trophy and the Yachtsman’s Cup Handicap Race for auto-boats in his cedar planked on an American elm frame, boat Scolopendra, named after, some say, a fictitious sea monster. She had a turtle-back foredeck and pine planked deck aft, covered with a serge canvas. The relatively low powered but efficient running 800kg boat had been entered as a substitute, when the forty footer being built especially for the contest was not ‘race ready’ (this boat may have also been named Scolopendra).
Thornycroft & Co were established builders of steam cars, commercial and military road vehicles, at Basingstoke; and steel torpedo boats for various foreign navies, at their Chiswick Yard on the Thames. Back in 1873, John Thornycroft produced one of the first motor torpedo boats, the steam powered, 458 hp, Gitana and she achieved 24 mph. Four years later, in 1877, Thornycroft took out several patents for skimming semi-displacement hulls, and for a revolutionary semi-submerged propeller.
* The Scolopendra changed ownership to a Mr. Tom Mittler, who sadly died June 2010. the current owner in 2015 is Graham Mackereth
Harmsworth (also known as the ‘British International’) Trophy and the Yachtsman's Cup (Handicap) 
The Automobile Club of Great Britain and Ireland, and its offshoot, the Marine Motor Association (MMA) planned to manage a race of auto-boats for a magnificent new prize, the Harmsworth Trophy in the summer of 1903. The race was to be run along similar lines and rules as automobile racing’s Gordon Bennett Cup, whose rules and conditions were in turn duplicated from sailing’s America’s Cup. The aim of all three trophies was that the contest should be a test of nations rather than individuals, and that the vehicles used should be constructed in the represented nation, and raced by citizens of that country. The inaugural 1903 Harmsworth auto-boat race was to be held in Queenstown Harbour, Cork, as a new dimension to the auto-car Gordon Bennett Cup race program.
Britain's Selwyn Francis Edge and the Napier race team were the current holders of the Gordon Bennett Cup, ‘the greatest automobile race in the World’. The defense should have been hosted in England, by the defending nation, but the government’s enforced ban of speed, in excess of 12mph, on the public highway, precluded the possibility. The Automobile Club decided to switch the races’ venue to Ireland.
Edge entered 3 cars for the Gordon Bennet Cup and a boat named after its engine Napier, for the Harmsworth Trophy.
Count Eliot Zborowski had suggested that each national entrant be allotted a different colour. Britain had to choose a different colour to its usual national colours, red, white and blue, because those colours had already been taken by USA, Germany and France respectively.
Racing Napier cars had been painted green in 1902, and it is said that as ‘a tribute to the Emerald Isle’, the whole British team in 1903 would be painted green. The phrase ‘British Racing Green’ and the expression ‘Gordon Bennett!’ (Synonymous with surprise), subsequently became a part of everyday language for subsequent generations of speed freaks.
In January 1903 John Thornycroft entered the first running of the Harmsworth Trophy and the Yachtsman’s Cup Handicap Race for auto-boats. He designed and built a forty foot launch, Champak, especially for the contest with 2 of 20 HP engines, but the performance proved disappointing. John Thornycroft had also commissioned Frank Maynard at Strand on the Green to build Scolopendra, a 30' hull of cedar planks on an American Elm frame boat to MMA Rules, with a pine planked turtle-back fore-deck, covered with “union Silk”. Scolopendra’s design was based on Thornycroft’s accumulated knowledge of Torpedo Boats, and featured the first “Slipper Stern”, though more commonly referred to as a Beaver Stern today. Scolopendra's performance in contrast had proven especially satisfactory, although only powered by Thornycroft’s new A4 20HP engine, at only 800 kg she achieved 18.2 mph. Scolopendra became therefore the entrant for races.
The Harmsworth Trophy has proved to be the longest standing competition for high speed motorboats.
2nd Heat. At quarter past three, Saturday 12 July. Due to the German entry Mercedes not being deemed eligible (due to running a French hull with a German motor) it was Thornycroft’s turn to qualify in Scolopendra, racing against the clock, on her own. If the qualifying 13 mph minimum speed was beaten a place in the Final was guaranteed. She succeeded.
3rd Final Heat. At twenty minutes to five, Saturday 12 July. It was high water and the stream now slack. Soon after the start, the Thornycroft launch, Scolopendra went into the lead. Napier had Alfred Harmsworth’s close friend, Campbell Muir, at the helm, and also on board was S F Edge’s close friend, professional chauffeuse, and the Womens’ World Land Speed Record holder, Miss Dorothy Levitt along with owner ‘SF’ in control of the engine. They soon passed the leading Thornycroft boat Scolopendra. Napier soon showed her superiority and went on to win at an average speed of 24.98 mph, crossing the line, more than a mile ahead of the competition, in a time of 24m 44s. In second place came Scolopendra in 30m 28s (20.28mph) and third Beadle’s Durandel in 37m 44s (16.37mph).
After the running of the Harmsworth Trophy Race, a handicap race for a cup donated by the proprietor of the Yachtsman Magazine was won by Scolopendra. She finished in third place on the water, again 5 minutes behind Edge but was allowed 11m 50s on Edges ‘scratch’ time and 6m 3s on Durandel’s handicap. Mr. Charley did not start the handicap race in Mercedes as he suffered from a ‘derangement of his machinery’ due to a lack of lubrication.
Although Scolopendra could not compete with Napier's power and outright speed, she went on to win many other handicap races such as the first Motor Boat Race at Cowes week, and she received much praise for being ”eyeable” and especially efficient. Many designers after 1904 imitated her hull lines, and many of the classic and most beautiful launches seen on the Thames today are based on her hull form.
The first HarmsworthTrophy Races 1903
1st Heat. Three o’clock, Saturday 12 July at The Battery of the Royal Cork Yacht Club, Queenstown Road, Ireland. The course was 10.3 miles, one way, up-stream, passing through the West Passage, with Black and Marino Points to starboard, to a large crowd waiting on the Promenade Quay, at the Cork Marina finish line, on the River Lee. There was a two knot flood tide flowing upstream. The start cannon banged and the two boat standing start was between Durandel and Napier. Durandel went into the lead. Napier showed her pace in the calming up-river water and went through to win by 3 minutes; Beadle’s Durandel completed the course well within the maximum fifty minute qualifying time.
Sold to Canada
Scolopendra was exhibited at the Crystal Palace Motor Show in January 1904, and sold from the stand to the Canadian shipyard owner Frederick Polson, who won a number of races in Toronto, before he sold her to the Canadian Govt as an armed high speed chase boat on the 3rd Class Cruisers “Petrel” and later “Vigilant”, for their Fishing War with US fishermen on Lake Erie.
About 1912, she was sold into private hands and raced in the Georgian Bay of Lake Huron, before being bought and restored. She was modernised by cutting off her Beaver Stern and replacing with a transom, and the fitting of a Buchanan engine. Scolopendra was used around Parry Sound for 40 years, for pleasure and as a work-boat in a cottage building and restoration business.
She came back to the UK in 2015 and is undergoing restoration.