The Esso Mercia is a large all-aft tanker, with a raised forecastle, a prominent projecting bulbous bow, and an AG Weser stern bulb,  she was built for the Esso Pitroleum Co. by AG Weser of Bremen, and is the largest tanker yet built in there yard. She is classified by the American Bureau of Shipping as + A I (E) Oi1 Carrier" +' AMS. Her principal particulars are: Length, o.a. 1,010.2 ft (307.90 rn) b.p. 950 ft (289.55 ni) Breadth, moulded 146 ft (44.40 m) Depth, to upper deck 76.4 ft (23.30 m) Draught, summer . . . . 59 ft (17.98 m) Deadweight, corresponding 166,820 tons Displacement, summer 194,083 tons Service speed 16 knots The hull is all-welded, and has a rounded gunwale plate. The cargo section is subdivided into five centre and ten wing tanks, sets Nos 1 and 5 being about twice as long as the others: the after ends of No. 5 wing tanks are partitioned off to serve as sludge tanks. The longitudinal bulkheads extend through the machinery space. serving as boundaries for wing bunker tanks. No. 2 wing tanks are used for water ballast only. Ballast is also carried in the fore and after peak tanks, in deep tanks forward and abaft the cargo scection, and in speciai wing tanks aft of the wing fuel bunkers. Nos 3 and 4 tank sets have been designed to act as flume-type roll stabilisers. Over-the top ballassting of selected cargo tanks which have been previously emptied is possible while oil cargo is being ischarged. The cargo-pumping system incorporates a centreline duct which is an integral part of the ship's structure. The independent cargo-stripping system is based on a conventional pipework layout, and is illustrated by a diagram. Oil cargo is handled by four AG Weser turbine-driven Eureka centrifugal pumps, each capable of discharging 3,000 tons/hr (sea water). There is also a turbine-driven ballast pump of the same capacity. The cargo stripping pump is of 365 tons/hr capacity. All cargo-handling operations can be carried out fromA a central control station located below the bridge, provided with remote control of all main cargo gate valves and remote indication of the ullage and temperature of each cargo tank. The gauging equipment has been provided by Dobbie Mclnnes Ltd. Hydraulic actuating motors, with mechanical connection to the valves, are located on deck for ease of maintenance. Deck mooring machinery is hydraulically operated, the power being supplied by three 300 h.p. electrically driven pumps located on the peak deck aft, and by a 900 b.h p. Paxman Ventura Diesel engine driving a hydraulic pump located under the forecastle deck. Among the equipment provided by the International Marine Radio Co. A is a 100-watt reserve transmitter, with " Mayday " RT facilities on 2,182 kc/s, which is claimed to be a unique feature. Safety equipment includes a foam mains system supplying a number of dispersing monitors located at intervals along the deck, and a remotely operated emergency fire pump, powered by the Diesel-hydraulic unit forward. There is air-conditioned accommodation for an " integrated " crew of 33, all in single cabins. Marinite veneered with laminated plastics was used for bulkheads, linings, and ceilings. The main engine is a non-reheat version of the MST-14 package-type steam-turbine set, built jointly by AG Weser and the designers (U.S. General Electric) who supplied the rotating parts. It is a two-casing cross-compound design with an axial-exhaust L.P. turbine, and has a rated output of 30,000 s.h.p. at 80 r.p.m. through dual torque-path reduction gearing. Inlet steam conditions are 850 lb/sq in, 950" F. The main machinery can be controlled from the bridge as well as from the machinery control room by a Siemens remote-control system. Siemens also provided mainmachinery instrumentation, including a 108-point data logger, and an efficiency computer. The Alcunic propeller has a diameter of 30 ft (9.2 m) and a pitch of 195 ft (6.64 mi); it weighs about 52'5 tons. The single main boiler is of a new design developed by Babcock & Wilcox in the U.K., and was built by their German associates in Oberhausen. This " i-Drum" boiler is the first of its type to be installed on board ship. (See Abstract No. 26,905, this issue.) The ship's A.C. supply is obtained from an AG Weser/Hansa turboalternator set of 1,000 kW outpit. The standby set has a 12-cylinder turbocharged Paxman Ventura Diesel engine (1,200 r.p.m.) coupled to a Hansa 750-kW alternator. The emergency set has a six-cylinder Paxman Diesel driving a Hansa alternator of 200 kW output.