MOTOR SHIPS

Evening Post, Volume CIII, Issue 55, 7 March 1922, Page 2

MOTOR SHIPS

% The _ world-wide depression in shipping is having its effect on Italian shipowners and shipbuilders, and as it is necessary that special attention should be naid to increased economy, the motor ship is attracting a good deal of interest among maritime nations, especially so among the Italians. It is a noteworthy fact that the Araito, a Diesel engine ship recently completed in Italy, was immediately chartered oy the Italian State Hallways for the transport of coal from Cardiff to Italian ports. The Roma Steam Navigation Company has just taken delivery of its first motor ship. The Vejo, as the vessel is named, was constructed by < the large Ansaldo combine at their shipyard at Spezia, and i? a cargo carrier of 8100 tons, with a length of 377 ft and a beam of 51ft. It is understood that she will be placed on the South American run. The owners of the Vejo have followed what is now common policy in connection with oil-engined vessels, and have adopted an entirely standard type of craft, similar to others which have previously been built. Within the past year or two, threo vessels of this class of exactly similar dimensions and engine power were constructed at the name yard for the Societa Nasionale di Navigazione of Genoa, and these have proved very satisfactory, having an average speed of between 9j and 10 knots ■with a fuel consumption of under 10 tons daily when carrying ■their full cargo. The machinery installation is unusual, since the motors are of a type unknown outside of Italy. They were constructed by the Ansaldo San Giorgio Company at Turn, and are of two-cycle design, although, as is well known, the four-cycle type has. been most popular among the majority of European shipowners. The engines are each designed to develop 1200 b.h.p. at 110 r.p.m., and they have only four cylinders, whereas with the four-cycle type six cylinders represent the minimum. The weight and space occupied are somewhat less than in corresponding four-cycle machinery, but the fuel consumption is slightly higher, although it is claimed by the builders that the differenoe does not exceed about 6 per cent. Like all other manufacturers of twocycle Diesel motors, the Ansaldo San Giorgio Company has adopted port scavenging, so that in each cylinder coyer there la, only a fuel valve and a starting valve, thus simplifying the construction to a considerable extent. The scavenging air, which is supplied from a vertical scavenging pump, driven off an extension of the crankshaft, is admitted to the cylinders through a single row of ports in the, bottom of the liner. In order to provide* effective scavenging and good combustion, the admission of the scavenging air in controlled by a double-beat valve arranged in the ccivenginir trunk, which does not allow the air to enter the cylinders until some time after the exhaust ports have been uncovered by the piston. This is a design adopted only by the Ansaldo San Giorgio Company. All the auxiliaries on the Vejo arc uterim driven, but in order that it may not be necessary to have an uneconomical oil-fired boiler :n operation rvt :iea, each engine derives allthe auxiliaries required for its operation, even inciuding a dynamo for providing; lighting imd power tor (ho eloumc steering gear, end an air compressor for working the steering engines. Tiiroo motor ehipa of similar dimensions r.vo to be built at the Spezia yard during the course of the present year.