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threaded buttress screws of forged steel; the screws are hung on collar bearings in cast steel brackets, which are supported by the framing-legs. The platform is built up of H gird- ers, closely pitched, connected at the ends to massive-built steel girders on each side of the vessel. The sup- porting screws are fitted with worm- wheels of special material, gearing at the lower with forged steel worms, working in oil baths. A sep- arate triple-expansion three-crank en- gine is fitted for the purpose of rais- ig or the main platform. This engine is of the inverted type and connects to the worms by ma- chine-cut bevel and spur-gearing of cast steel; automatic gear is fitted on this engine to prevent the platform being raised or lowered beyond its intended travel. A brass indexed telltale is also fitted in a prominent position in. the engine room to show in feet and inches the position of the platform. ends lowering The lower or main deck is of steel- plating and has no 'projections above 10 in., to enable the elevating platform to come to its lowest level. The main propelling engines are of the vertical three-crank triple-expan- sion type, each egine driving two pro- pellers, one forward and one aft; two thrust-blocks are fitted on each line of shafting. The engines are controlled from the house on the top of the framing by balanced rods, the latter actuating the steam valves on the direct-acting steam and hydraulic reversing engines. There are no rudders, the vessel be- ing maneuvered entirely by the pro- pelling machinery. In the control- ing-house the two reversing handles are situated one on each side of the steersman's position. Two Chadburn's direction telltales and tachometers are provided and fixed in this house, giving the number of revolutions and direction of the propelling engines. Chadburn's telegraphs to main and elevating engines are also fitted; the former. are only intended for use in case of emergency. Steam is provided by two return- tube marine boilers, having a working Pressure of 160 Ib. per sq. in. The main condenser is separate from the main engines and is fitted with two of Baker's exhaust-steam purifiers. The air pumps are independent and Steam-driven by two-crank compound engines, and are in duplicate, one set being kept as a standby. This also applies to the independent centrifugal "'TAE Marine REviEw circulating pumps. fitted throughiout. The boiler feeding is effected by Weir's automatic float tank pumps, the feed water passing through a Weir heater and Harris filter before enter- ing the boilers. Cameron's pump is fitted for bilge and wash-deck ser- vice. The vessel throughout is of mas- sive design, all parts having been carefully constructed for their respec- Electric light is 45 tive purposes. The platform is in- tended to carry 16 loaded lorries, but with a mixed cargo as many as 20 vehicles can be accommodated on board. After successfully passing through her stability and steaming tests the vessel was put to work on her station and has given entire satisfaction. The vessel was built to British Corpora- tion Survey, and has a board of trade certificate--Engineer, London. Board of Trade Rules for Steel Boiler Materials. The following circular on "The Manu- facture and Testing of Steel Material In- tended for Boilers and Machinery under Board of Trade Survey" has been issued 'by the Marine Department of the Board of Trade: 1. Introduction.--The board have had under consideration the reports issued by the Engineering Standards Committee re- lating to structural steel for marine boil- ers, ingot steel forgings for marine pur- poses, and steel castings for marine pur- poses; and have prepared the following amended instructions for the guidance of their surveyors. 2. Date of Enforcement.--These. in- structions will come in force on Aug. 1, 1908, but in any case in which engineers, boilermakers, or steel manufacturers de- sire it, they may be adopted at once. GENERAL CONDITIONS. 3. Process of Manufacture.--All steel intended for use in the construction of boilers and for forgings shall be made by the open-hearth process. Boiler plates shall be of acid quality; but the other portions of boilers and forgings may be made of either acid or basic steel. In the case of castings, the steel may be made by any process which has been approved by the Board of Trade. 4. Freedom from Defects and Treat- ment of Test Pieces--The finished ma- terial shall be sound and free from cracks, surface flaws, and laminations. No ham- mer dressing, patching, burning, or elec- tric welding is permissible, and if any ma-- terial is annealed or otherwise heat- treated, the test pieces shall be similarly and simultaneously treated with the ma- terial before they are tested. No further heating or forging of the specimens may be done, and all the necessary preparation shall be made in a machine. 5. Selection of Test Pieces.--All the test pieces required shall be selected by. the surveyor, and except where otherwise specified, the tests shall be made in his presence at the place of manufacture, and before the dispatch of the material; and the stamping of test pieces shall be done after all the heating or annealing is com- pleted. 6. Number of Tests in Certain Cases. --When a number of articles are cut from one plate, bar, or forging, the num- ber of.tests required shall be the same as that required from the original piece, pro- vided the articles have not been further heated or forged, and can be identified as having formed part of the original piece. When a number of small forgings are made from the same ingot, or a number of small castings from the same charge of steel, the full number of tests speci- fied herein need not be made; tensile and bending tests at the rate of one for every four articles will, as a rule, in such cases be sufficient. 7. Duplicate Tesits--Should either a tensile or a bend test fail to fulfil the test requirements, and the surveyor considers that the test piece does not fairly repre-. sent the quality of the material, two dup- licate specimens may, if the maker wishes, be tested; and if the results ob- tained from both are satisfactory, the quality of the article shall be judged therefrom and not from the original test which failed. If, however, either of the duplicate test fails, the article or articles represented shall be rejected. _ 8. Stamping of Material_--Every arti- cle shall be stamped with a number or identification marks such that the charge of steel from which it was made can be readily identified. In addition to this, plates and bars shall be stamped with the maker's name or trade mark, and plates with results of any test which are made from them. ay 9. Material Proving Unsatisfactory to be Rejected.--In the event of any ma- terial proving unsatisfactory in the course of working or machining, it-shall be re- jected notwithstanding any previous cer- tification of satisfactory testing. 10. Special Instructions.--The special snstructions contained in Circular 1382 respecting steel material for which certi-