The age-herald., 1898-08-05
CURRENT COMMENTS 2 OF THE DAY

paftment eXnlDlt at that place a Hou II oi
 a dry dock. The pressing need for more
 dry docks in order to take proper care or
 the ships of our navy and the ignor ince CT
 the people away from the sea eoast ef
 what a dry dock was, led Lieutenant Me-
 Cormick, who had charge ot the exhib't | to suggest to the chief naval consli uctor | the construction of a working nc del or
 such a dock, and it has been butt turing
 the past winter. The model is constructed
 of wood, but the inside is lined with trass
 plates brazed together in order to make it
 water-tight. It is said to be exact re- 1 production of the timber dry docks nheh | are to be built at ,he Portsmouth. I'aila- 1 delphia and Mare Island navy yards, and in 1 size and general dimensions of the new 1 dry dock at the Boston navy yarl.
 The model has been prepared in grt at
 detail so that the model ship which accom-
 panies it can be docked and unlocked just
 as the actual ship would be. A large basin
 is constructed outside the entrance in
 which the model ship win be loated. and
 complete system of piping and valves is provided so that the dock can be ooded | allowing the model ship to enter and then drained, leaving her dry on the blocks.
 railing surrounds the three land sides Of 1 the dock which is a working model of l a powerful travelling crane, used for han
 ding heavy weights which may need to be l taken aboard of or removed from a ship
 in the dock
 The ship model which is part of the ex-
 hibit, is accurate reproduction on the
 same scale of the battleships Illinois, Ala | bama and Wisconsin, which are now being l built.
 1 t The plans for raising the sunken Span l ish ships are said to involve adaptations of principles that have been heretofore used, | but it makes these methods none the less
 interesting. The raising of the Cristobal | Colon, as is well known, is one of the up- 1 permost questions at present, the fear be- l ing that in raising her from the ends she
 will break in the middle where the engines | and a great deal of heavy machinery are | located The mechanical problem will be solved by a system of pontoons and air
 bags, after derricks of strong power, mounted on floats, have frightened the bat | tleship by raising the guns and the movable parts of the machinery. Experienced di- | vers will be sent down to close up every 1 aperture that can be closed; air bags will | be placed in the hatchways, and will be eN'AN | angles between the deck and the side. The | bags will be inserted in a collapsed condi- | ton, and then pumped full of air, thereby l dispacng water equal in size to their bulk
 These bags are made to displace from | few tons to several hundred tons. By fill- l ing all the availabld space within the ship and thereby expelling water, the ship is ex- pected to be made sufficiently light to be rai. Nv, nf ha | These pontoons are described as resem- | bling a canal boat or a box car, and are | utterly unlike the pontoon bridges made of boats, with which the general public is ! familiar The pontoons will be filled with water and sunk, and then be fastened to the ship where most available by means of | immense chains. Heavy chains will be run | beneath the ~pontoons and under the ship and brought around the ship from the oth-
 CT side and secured. The water will be then expelled from the pontoons, and as they lift the ship from the rear side be- meath the chains by means of derricks will pull the ship over from the far side The wreckng outfit includes an air com
 pressing plant, by which the machinery is operated. The pontoons will be sunk at low tide and raised at high tide, and every
 
 will be pushed in shore. This process will
 be repeated until she is brought far enough out of the water to enable the openings in her hull to be closed and such needed re- pairs made that she can be lowed to this country
 A torpedo boat of a new type has recent ly been launched in England. It is con- structed of mild steel below the water line, the upper part being Of a special descrip-
 ton of hard steel, having higher tensile
 strength than the ordinary steel, thus all lowing the scantling to be much lighter. The following gives an idea of the speed
 and machinery: The armament will con-
 sist of one 12-pounder quick-firing gun and five 6-pounders. There are also two 1S-
 inch torpedo tubes on deck. The propeiling
 machinery consists of two sets of ,hree
 stage compound engines, each having four cylinders. These are 22-inch and S3lh-inch for the high-pressure and intermediate pressure cylinders respectively, pnd 36 inch
 each for the two low-pressuce cylinders,
 the stroke of all being 20 inches. Steam is | supplied by three water-tube boilers of the Daring type. They will work al ;to-po, .nds pressure, this being an increase on the former practice, 2l0 pounds to the square inch being the maximum pressure hitherto carried on these vessa els. Al a5out 400 rcvG- | lutions per minute the estimated ho.rse- power will be 5000 indicated, and this is | calculated to give speed of 92 knots that | being the guaranteed speed. The fastest destroyer now afioat is the Desperate. She | made 31,O34 knots on preliminary trial of | three hours duration.
 TIE PRICE OF GOOD GUNNERY 1 From Life.
 From the standpoint of MT. Cunning ham, Graham, English gunners come high.