[29] Troops cannot be landed with as little delay as this. But naval tactics assume as a matter of course that an advance body of bluejackets, trained for beach and surf work, can effect an immediate landing if protected from attack.
[30] Lord Cochran landed 18,000 men on the open coast of Chile in five hours, with some guns. The surf conditions there are extremely hazardous.
[31] American submarines now in commission do not carry more than one 3-inch rapid fire gun. It is set in a watertight compartment from which it is elevated when the vessel is on the surface. Armaments of destroyers are: Ammen class, five 3-inch rapid fire 30 cal. rifles; Aylwin class, four 4-inch rapid fire 50 cal. rifles; Bainbridge class, two 3-inch rifles and five 6-pounders rapid fire.
[32] Submarine wire entanglements are being used effectively for the protection of harbors during the present war. The wire cannot resist cutting much more than twine can. It stops the submarine by menacing it with being entangled and trapped. A submarine caught under water cannot be cleared by its crew. The utmost the men can do is to try to reach the surface by putting on “special escape helmets” and emerging through the air-locks.
[33] With periscopes shot away, a submarine, even though uninjured, is quite helpless. She may escape, if she is in deep water and the assailant is far enough away to give her time to dive and flee, deeply submerged. See loss of U-12 on March 10 merely through destruction of periscope, which permitted enemy destroyers to ram her.
[34] Even steam vessels of high power often are rendered helpless by jamming a trailing hawser around the shaft. The revolution of the shaft so macerates and binds the fouled material that the engines are unable to turn the propellor in either direction and only a diver can clear it.
[35] The reserve buoyancy of a submarine when awash (technically known as “diving-trim”) is so delicate that 100 additional gallons of water would sink a 300-ton vessel.
[36] “From an altitude of 2,000 feet the movements of a submarine torpedo boat may be easily observed unless the water is very muddy”—Capt. V. E. Clark, Aviation Corps, U. S. A., December issue, Coast Artillery Journal.
[37] Important cities in this territory besides New York and Boston are Fall River, Providence, New Bedford, New London, Bridgeport, New Haven, Hartford, Worcester, Springfield, Willimantic and Pawtucket.
[38] Colonel Abbott, U. S. A., one of the leading Chiefs of Engineers who constructed the U. S. harbor defenses, stated that the fire of the sixteen mortars, “like one giant musket throwing a charge of buckshot, each pellet weighing ¼ ton,” could drop their sixteen projectiles into a space 800 feet long by 300 feet wide. The author was present at a test of a 16-mortar battery on Sandy Hook when the sixteen shells were fired simultaneously at a deck-plan of the United States cruiser San Francisco, the plan being outlined with stakes on the New Jersey beach five and a half miles from the battery. Each projectile struck inside of the staked outline.