[Illustration: THE NEW DREDGER AJAX.]

The Ajax is almost a duplicate of the last dredger designed by Mr. Ferris
for levee building on Roberts Island, with such modifications and
improvements as have suggested themselves in the two years it has been
working.

The hull, oval in plan, is 36 ft. 10 in. by 60 ft. over all; it has four
solid fore and aft bulkheads, and a well hole 5 × 12 ft. at one end for
the bucket ladder.

The main engine is 10 × 24, operating, by bevel gearing and a 3½ in.
vertical shaft, a 4 sided upper tumbler with 21 in. sides. This engine
works also a gypsy shaft for swinging, and the conveyer that carries the
mud ashore. A steam hoist with 6 × 11 engines raises and lowers the
bucket ladder. The buckets, at 4 foot centers, have a struck capacity of
5 cubic feet, and are speeded to deliver from 18 to 20 a minute,
according to the character of the material being handled. They are of
boiler iron, with a 5 in. steel nosing. The links are of wrought iron,
with cast bushings. The lower tumbler is hexagonal, on a 4 in. shaft.

The conveyer, projecting 72 ft. from the center of the boat, consists of
a 5 ply rubber belt 36 in. wide; running over iron drums at each end and
intermediate iron friction rollers at 3 foot centers. Ratchet and pinion
on each side of conveyer ladder give means for taking up the slack of the
belt and adjusting the drums to maintain them parallel.

This conveyer is the important feature of the dredge. It is entirely
satisfactory in its working and delivers its material, as nearly as may