In another of his occasional articles, R.T.Pole discusses what must surely be the prettiest tethered hydro ever built, Mr L.J French’s ‘Little Star’, which was the 15cc record holder from 1936-38.

Little Star by R.T.Pole

A ‘polysphenic ship’ was the term used by the Rev. C.M. Ramus in 1870 to describe his 29½" long rocket powered model hydroplane which featured two steps and three equispaced planning surfaces, the literal meaning of polysphenic being many wedges.

Over the years since 1870 the multi-stepped hull has been tried many times and the most successful of these was built in 1935 by Lionel French, who had stated in a 1930 Model Engineer, that a multi-step hull could never be as conducive to flat-out speed as a single step hull.

The illustration shows the hull lines of Little Star, which at one time were available from Model Engineer for the princely sum of one shilling and eight pence (8p) post free.
 

The materials used in construction of the hull are as follows; Bulkheads 3mm, 3 ply, transom 12mm 9 ply. The stem, keel of front plane and centre deck beam from 6mm 5 ply, and the deck sides, middle and rear planes from 1 1/2mm 3 ply.

To achieve the concave vee at the front plane two layers of .75mm 3 ply were laid at 90 degrees to each other in narrow strips, butt jointed and well glued with ‘Le pages’. All stringers were ¼" square satin walnut and the sections S2 and S3 were thickened out to take the deep angle aluminium bearers.

Although the thrust line on the plan indicates an articulated driveline, the original had a straight shaft, but was changed, as it proved unsuccessful. The propeller was placed in front of the tail skeg and measured 2 5/8" diameter x only 3 ½" pitch, which was much lower than the norm and allowed the engine to run up to 15,000 rpm.

The engine was a single cylinder 4-stroke of 1in. bore x 1 1/8in. stroke giving a capacity of 15cc, and was unusual in having forced lubrication and oil cooling built in. The cast iron cylinder barrel screwed into the oil sleeve of the crankcase, being secured by a locking ring, which allowed variation of the compression ratio, normally set to 8:1. The bronze cylinder head in turn screwed onto the cylinder, being drawn up to final tightness with a draw screw. A high set camshaft operated through parallel pushrods, narrow angle inclined valves of 15/32in. dia. made from K.E. .965 steel and fitted with hairpin springs of 12-14lbs. tension.

The piston, which had .002in clearance at the top of its stroke, was attached to an H section Duralumin con-rod with a ball raced big end. The overhung crankshaft was supported by a single ball race at the web end and a phosphor bronze bearing at the other, the crankcase and timing gear case being all cast from aluminium with two substantial mounting lugs either side inline with the crankshaft.

A low-level brass fuel tank, filled with a 50-50 petrol-benzole mix was pressure fed to the carburettor, which had a single submerged jet with slot and well compensation. The finished all up weight od the boat was 6lb 14oz not including fuel.

On its first outing in late December 1935 a speed of 24.74 mph was recorded, which equalled the then current class record set by Captain C.E. Bowden’s Jildi Junior. Unfortunately the distance covered in the run was slightly less than the 300 yards specified for the ME Speedboat Competition and record ratification and was therefore disallowed. However, early the following year (1936) a speed of 34.86 mph was recorded over the 300 yard distance. This record also gained Mr French the ‘C’ class award in that year’s ME Speedboat Competition. Over the next three years Little Star was run at most of the London area regattas but never again achieved its record speeds.

 

Postscript. ‘Little Star’ did not appear at all after the Second War and was effectively ’lost’ until 1987 when Mr P.E. Hill managed to contact Mr French and discovered that ‘Little Star’ was still nearly all in one piece.

It transpired that Mr French’s interests had changed after the Second World War and the boat had not been run at regattas since 1940. The engine had been bench run, ‘off load’, on several occasions, and on one of these tests 27,000rpm was claimed.

Mr French’s new interest was motor cycle racing and he competed in the I.O.M TT races on five occasions. He raced in the Clubmans classes in 1948/49/51 and the TT itself in 1952 on an E.M.C Puch, finishing 11^th, and in 1953 on a Sulby-EMC he had built himself, retiring from the race. A racing crash put an end to his riding career but he continued his involvement, by sponsoring other people.

L.J. French lightly restored the boat he had built 52 years previously and in 1988 passed it to Mr Hill for safe keeping. ‘Little Star’ was then put on display at the Power Boat Museum at Pitsea where it remained until the redevelopment in 2008.

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