Unique Slipway Launch Of Aft Part Of Hull Performed At 3.Maj Yard
The 3.Maj Shipyard in Rijeka, Yugoslavia, recently launched the aft hull part of newbuilding No. 643 down sliding Slipway No. 1, a new technology for the use of inclined ways.
The decision to build Hull No. 643, a 25,500/34,950-dwt bulkcarrier on Slipway No. 1 entailed a problem. The hull was designed with an overall length of 728.7 feet, and the slipway is serviced by cranes to the length of about 640 feet.
The solution to the problem by moving the aft part hull, comprising the engine room and Hold No. 7, in the direction of the slipway's front for a length of 11.8 feet. Construction of the hull was in two parts — engine room and one part of Hold No. 7, and the other part from Hold No. 4 forward to the bow. The distance between the two parts was about 8.2 feet.
Both parts of the hull were supported, as usual, by sand-filled blocks. The aft part, in anticipation of the eventual sliding-down operation, was set 120 mm higher than the bow part. After completion of the aft hull and the usual extent of engine room outfitting, preparations began for the sliding-down operation. By use of steel wire ropes the aft hull was secured to the Goliath Gantry Crane that spans two slipways. By employing constant force from the gantry, tbe aft part was guided down the sliding ways at a constant speed of just under 2 feet per minute for the total distance of 114.8 feet. The aft hull was stopped by effecting increased force from the gantry. After having been stopped, the aft hull was accurately positioned longitudinally and transversely by means of hydraulic presses, and then lowered by letting the sand flow out of the supporting blocks.
The complete operation, including sliding down, accurate positioning, and lowering of the hull part was carried out during two working days. A section containing Holds No. 5 and 6 was then inserted between the aft hull and the bow part.
When completed, Hull No. 643 will have an overall length of 728.7 feet, beam of 75.7 feet, depth of 48.4 feet, and draft of 26/31.8 feet. For further information on the 3.Maj Shipyard,