SKIMMING BOATS.

Cromwell Argus, Volume XLI, Issue 2206, 1 August 1910, Page 2

SKIMMING BOATS.

Of recent years quite a number of small vessels, built primarily for racing purposes, have been evolved usually termed "hydroplanes," having two or more inclined surfaces, and some very remarkable speeds have been attained with them.

This high speed is accounted for by the fact that such vessels glide over the water with comparatively small resistance, being lifted by the action of the fluid against the inclined planes of which the bottom of the vessel is composed. When the water strikes any part of these oblique surfaces it must either be driven vertically downwards or it must escape laterally, or it must lift the boat vertically upwards. When the vessel is at rest and floating in the water the wedges are submerged, and while the speed of the vessel is moderate they still remain submerged ; but as the speed increases, the action of the water gradually causes the whole vessel to be lifted bodily until at high speed the area exposed to frictional action ia simply the residuary under-surface of the planes which supplies the support, since the speed of transit almost entirely denudes the sides of contact with the water. HYDROPLANE SPEEDS. The great advantages of the hydroplane are not only the reduction of the draught and displacement of water, but the hydroplanes reduce considerably the amount of friction surface in contact with the water, as well as minimising the loss by friction of that portion of the surfaces actually in contact, as previously explained. We are all sceptical as to the practical utility of an invention, be it ever so plausible in theory ; but the inventor has already obtained some really astonishing results with vessels actually built on these lines. It is true these are only small boats ; but, unlike the usual type of hydroplane, they conform more to the ordinary shape of a boat above water, and are capable of comfortably seating several persons. In one such vessel a speed of 34 miles an hour was attained with six passengers aboard, and with a lower number of passengers in a speed test no less than 37£ miles an hour was recorded, and this with only GO horsepower.—C Johnstone, in "Cassier's Magazine." 1711.