The hopper dredger "La Puissante" (Plate I. fig. 4), constructed by Messrs Wm. Simons & Co. for the Suez Canal Co. for the improvement of Port Said Roads, is a fine example of this class of dredger. She is 275 ft. long by 47 ft. beam by 19 ft. deep. The hopper capacity is 2000 tons, and the draught loaded 16 ft. 5 in. The maximum dredging depth is 40 ft., and the minimum dredging depth is only limited by the vessel's draught, she being able to cut her own way. The bucket ladder works through the well in the stern and weighs with buckets 120 tons. The buckets have each a capacity of 30 cub. ft. and raised on trial 1600 tons per hour. The dredger is propelled by two sets of independent triple expansion surface-condensing engines of 1800 i.h.p. combined, working with steam at 160 lb. pressure, supplied by two mild steel multitubular boilers. Each set of engines is capable of driving the buckets independently at speeds of 16 and 20 buckets per minute. The bucket ladder is fitted with buffer springs at its upper end to lessen the shock when working in a seaway. The dredger can deliver the dredged material either into its own hopper or into barges lying on either side. The vessel obtained a speed of 9¾ knots per hour on trial. The coal consumption during 6 hours' steaming trial was 1.66 lb. per i.h.p. hour. Fig. 9 (Plate I.) shows a still larger hopper dredger by the same constructors. _Dredgers fitted with Long Shoot or Shore Delivering Apparatus._--The first instance of dredgers being fitted with long shoots was in the Suez Canal. The soil in the lakes was very variable, the surface being generally loose mud which lay in some places in the sand, but frequently more or less on hard clay. Resort was had to shoots 230 ft. long, supported on pontoons connected with the hull of the dredger. The sand flowed away with a moderate supply of water to the shoots when they were fixed at an inclination of about 1 in 20, but when the sand was mixed with shells these formed a coating which prevented the stream of water from washing out the shoot, and even with an inclination of 1 in 10 material could not be delivered. A pair of endless chains working down the long shoot overcame the difficulty, and also enabled hard clay in lumps to be dealt with. One dredger turned out about 2000 cub. yds. of thick clay in 15 hours, and when the clay was not hard it could deliver 150,000 cub. yds. in a month for several consecutive months.