CS97 – Ferralium 255 – Water Propellers

The Vosper-Thornycroft VT1 hovercraft was designed for propulsion by water propellers mounted on skegs beneath the craft. One of the advantages of this system is that it provides good manoeuvring at slow speed in conditions of crosswind.

The photographs of the blades, manufactured by Vosper-Thornycroft VT1 for the K.M.W./Stones variable pitch propellers as used in the VT1 hovercraft operating between Malmo and Copenhagen in the summer of 1972 are beautiful examples of production machining and reflect credit on both the designers and the manufacturers. The excellent surface is apparent, and is a tribute also, to the high quality of the castings.

The Langley castings used are in FERRALIUM 255 alloy (UNS S32550, Alloy 255, DIN 1.4507, ASTM F61). Ferralium 255 is a super duplex stainless steel which is becoming increasing specified for marine applications, where mechanical strength, toughness and corrosion resistance are essential to long and efficient service life. The screw blades shown each weigh 16lb. and the complete screw has a diameter of 25 inches. It has completed some 100 hours of trouble-free operation.

If you’d like more information regarding Ferralium 255, please get in touch with a member our expert team today.