A NEW TYPE OF DREDGER.

Wanganui Chronicle, Volume L, Issue 12710, 22 March 1911, Page 2

A NEW TYPE OF DREDGER.

Meesrs William Simons and Co., Ltd., Renfrew, launched towards the end oflast year, to the order of the Director of Works of the British Admiralty, a "Simons" patent cutter suction hepper dredger named St. Laurence, of 2000 tons hopper capacity. Dredging clay aiid other hai-ci material bj' means of a spiral cutter—the method adopted in dredgo building, the St. Lawrence being the first of her typ^ constructed iit the Vnitod Kingdom. Tho arrangements of the vessc"! are as follows:— There is an independent set cf triple-expansion engines for driving the dredging pump, and a complete installation of auxiliary machinery fitted in a separate en^ jjine room immediately in front of the liopper^ compartment. Steam for the propelling and pumping engines and for cAI other machinery throughout the dredger is supplied by thre-e marine typo fite-fl boilers.

Tho dredging pump is of the most massive ar.d powerful description in order to withstand the shocks which may bo sustained whon dredging in clay mixed with stones. The suction pips is carried on a girder led through a well forward, and is of sufficient length to enable dredging to be done at a d.pth of <35ft. ix-low water line. Tho dredger hn.s also been designed for cutting its own flotation. The cutter at tho mouth of the suction pipe is driven through a line* of shafting fitted on the uppc-r side, of the suction frame and machino cut steel gearing actuated by a set of powerful, independent, com-pouud-cendensing engines. In addition to ibo usual winches for mooring from the deck at bow and| stern, a special winch is placed amidship, from which the moorings are led along the suction frame to fairloads at the lower end. The- hopper is fitted, with "Simons" patent arrangements whereby the contents can be discharged either through tho doors in the ordinary way or override by the pump for land reclamation. In addition,to loadiag into its own hoppor, the vessel is arranged to discharge into bivrges moored alongside or through a pipo line.

Two sets of triple expansion, surface■conrlensing engines are fitted aft fo>-pro-pelling the ves.se-1 at a speed of ten knots. The auxiliary machinery in the propelling engine-robm h of thci most up-to-date character. The dredger has been built under special survey by JJoyd's and to their full requirements Jhe berth adjacent to the. ons from which the St. Lawrence was launched is occurred by an almost similar dredger building to tlie ordeu- of tho Governmccit of ths Union of South Africa,