George. — Description of Patent Slip at Wellington. 17 



of the vessel to be raised. Small blocks or pulleys ai'e fixed in positions to 

 guide the ropes in the proper directions, both for the sliding blocks and 

 the palls. 



The steam engines for working the slip consist of two 25 horse- 

 power horizontal high-pressure engines, manufactured by Messrs Appleby 

 Brothers, of London. Steam is supplied to the engines by two single-flued 

 circular boilers, 30 ft. in length and 5 ft. in diameter. They are erected in a 

 building about 50 ft. distant from the engine house. The reason for placing 

 them so far distant was to avoid the expense of a heavy cutting that would 

 have been required to place them close to the engines. It is not found that 

 any loss is sustained beyond the expenditure of steam necessary to warm the 

 steam-pipe in the first instance, the steam-pipe being, of course, covered in with 

 hair-felt. The boilers are supplied with water by means of a GiSard's patent 

 injector, but can also be supplied by the pumps attached to the engines ; 

 the usual pressure gauges, safety-valves, blow-ofi" cocks, etc., being also fixed. 

 The boilers were constructed at Messrs. Kennard Brothers' works at Crumlin, 

 being sent out to the colony in sheets, and rivetted together on the work. They 

 were tested, by hydraulic pressure, to upwards of 100 lbs. to the square inch 

 before being set into their places in brickwork ; the usual pressure at which 

 they are worked when a vessel is being raised is 45 lbs. to 50 lbs. to the 

 square inch. 



The engines are attached to a train of wheels, or winch, which, when 

 working in slow purchase, multiply the power of the engines seventeen times, 

 while a quicker purchase multiplies the power of the engines nine times. There 

 are seven cog-wheels in the winch, the last and largest being fixed on a shaft 

 of 14 in. diametex', on which the chain wheels work ; the wheel for the large 

 chain being 7 ft. in diameter, and for the small chain 9 ft. These wheels are 

 loose on the shaft, and are put in gear by means of a clutch worked with a 

 screw and hand-wheel. The chain wheels ai-e grooved to take the chain, 

 having suitable teeth cast in the groove for each altei^nate link of the chain to 

 bear upon. The hauling-up chain is 1,700 ft. in length, and made of iron 

 Sin. in diameter, each stud link being 18 in. in length. For small vessels of 

 500 tons or under, this chain is worked single, being shackled round the 

 pulley wheel at the head of the cradle ; but when it is required to raise a large 

 vessel the chain is worked double, the return end being secured to an anchor 

 block fixed in a suitable position near the winding engine. The small chain, 

 or lowering-out chain, is of l:|in. iron, one-half being made in lojiir links to 

 suit the teeth of the wheel, and the remainder in lengths of ordinary short-link 

 chain shackled together. This chain is secured in the form of an endless 

 chain, both ends being shackled to the head of the carriage. A pulley wheel 

 is fixed at about 165 ft. from the outer end of the ways, round which the 



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