DREDGE RESUMES WORK

Timaru Herald, Volume CXXXVII, Issue 19668, 9 December 1933, Page 8

DREDGE RESUMES WORK

CLEARING SILT FROM CHANNEL VISIT TO VESSEL Very few of the thousands of people who from the shore have watched the Timaru Harbour Board's dredge No. 350 at work near the harbour entrance, realise the extent of the operations of a vessel which is in reality a floating mass of machinery and power. To the officers and crew of the dredge, however, the clearing of tons of silt from the ocean bottom is just part of the daily routine, and many years of dredging activity have brought their work to the highest state of efficiency. This was the impression gained by a representative of -The Timaru Herald.’* who was yesterday ferried across to the vessel from the Marine Parade to spend a very interesting morning on board. No. 350, which has served the port faithfully and well for the last 26 years, has, after a period of idleness jutfc been re-commissioned following a visit to Port Chalmers for her annual overhaul and refit, and yesterday she was engaged at the elbow or* the middle cut of the harbour channel dredging to a depth of 32 feet.

Mud and River Deposit. Th? system of chain dredging which is carried out at Timaru is governed by forward and aft winches which each regulate three chains, the middle one of which controls the depth into the face, while the two on the sides traverse the cut. Efech chain is anchored. The dredging line to be taken is indicated on the shore by surveyed marks which determine the width of the cut. The huge iron ladder on which the buckets revolve is also regulated according to the cut, and at a maximum dredging depth of 40 feet, it is at an angle of 45 degrees. Yesterday the buckets were cutting their way into mud and river deposit which travels along the coast and comes to rest in the channel, which it is estimated has silted up five feet at the elbow since the time the dredge was last operating there. This class of dredging, it was explained, was comparatively easy, but the work was expected to become harder further out where there were prospects of heavier silt. Each bucket as it rumbled its way up the ladder, contained about half a cubic yard of material, and three bucketsful, it is estimated, would easily fIU an ordinary horse dray.

Ready for Dumping. After about two and a half hours* :iredging yesterday morning the huge hoppers began to overflow, and the vessel was made ready to proceed to the dumping ground about two or three miles along the coast near Washdyke. The vessel is capable of carrying about three loads a day, but it is considered by the officers that two good loads a day are better than three smaller ones.

Before Captain McLachlan took nis post on the bridge and the engine room telegraph was rung for steam, the chains and moorings were bridled together with a chain strung on the centre chain. A 15 fathom wire was made fast to the centre chain and the end taken to two small working boats, where it was held until the centre chain was slipped. The wire was held while the vessel proceeded for dumping, and was ready for picking up on return. The system of picking up was very favourably commented on by Mr J. Appleton, technical director for Messrs Fleming and Ferguson, makers of the vessel, who said, after a visit to the dredge, that it was the best method he had ever seen. By sending the vessel slightly astern the buckets were completely emptied and the ladder heaved to the deck, fenders being fitted to take up any swaying motion caused by the action of the sea when the ship was under way. The signal for full speed ahead was telegraphed to the engine room at 11.34 and after steaming at seven knots the dredge soon reached the dumping ground. The wedges holding the doors of the hopper in place were knocked out and the bottom of the vast container was sung down and the silt deposited into the sea. All that could be seen of the 1000 tons of material was a discolouration on the surface of the water. On the return journey the hopper was closed again by a steam winch, and five minutes after the anchorage was reached the vessel had been made fast and the buckets were ploughing their way into the sea bottom in search of silt for another load. Vessel in Good Order. The dredgemaster (Mr W. R. Hayne) who conducted the reporter over the ship, expressed himself as well pleased with the condition of the vessel and the dredging apparatus since her overhaul at Port Chalmers. The work carried out at Timaru during the time she was laid up had also been of inestimable benefit. He considered that the present work in the channel would occupy about three months.