This little vessel, the Aronia, typical of many modern yachts and thus not a merchant ship, is included in this series for convenience. She is propelled by diesel engines and her hull is of a form known as the “toothpick” type. She was built and engined in Denmark and the drawings show that she has a hull form somewhat similar to that of a torpedo-boat destroyer. This is particularly marked in the cruiser stern, the arrangement of propellers and the spade rudder. She has twin screws. Her length is 135 feet, her beam 17 ft. 6 in. and her depth 11 feet. Her minimum draught in service is 7 ft. 6 in. and her speed with the twin screws is 15½ knots.
A “superstructure” in the shape of a casing just over 3 feet in height runs aft from the forecastle and ends in a big saloon on the after deck. The two funnels, one an exhaust and the other a dummy, are on this casing top. The dummy funnel is fitted at the break of the forecastle and the after funnel takes the exhaust from the diesel engines. The structure of the hull is of the usual frame and reverse frame style associated with ships of this type, but fuel-oil double-bottom tanks, with a total capacity of about 12 tons, are arranged immediately forward of the engine-room and between the auxiliary engine seatings.
Propulsion is carried out by two six-cylinder, two-cycle, single-acting airless injection engines. These are trunk piston units and rated for 590 indicated horse-power, or about 450 brake horse-power at 400 revolutions a minute. The total power output of the ship is thus 1,180 indicated horse-power.
Each main engine is fitted with a rotary cooling water pump driven from the end of the crankshaft which, in addition, drives a lubricating oil pump of the gear-wheel type as well as a rotary bilge pump. Scavenge air is supplied by two rotary blowers, of the Burmeister & Wain patented type, driven from the main engines through chain drives. Eleven tons of fresh water are carried in two tanks in the engine-room, in the double bottom tank abaft the engine-room and in the aft peak tank.