Table for ascertaining Velocity of Tide by noting the number of seconds a measured knot of 473 feet takes to run out. NOTE.-Three or four knots should be timed, and the mean taken. Table showing the Number of Feet subtending an Angle of 1' at given distances to 32 Nautical Miles. ONE FOOT SUBTENDS AN ANGLE OF 1' AT A DISTANCE OF 3437' 75 FEET. This Table shows the error in height which would result from an error of 1' (and, by multiplication, of any small number of minutes) in the altitude. Again, it gives very nearly the magnitude of an object at a given distance, and subtending an angle not exceeding 2° or 3°, by multiplying the number of feet against the distance in the Table by the number of minutes in the angle subtended. The length of an arc-No. of degrees x radius × 07145. Section 6. BOATS. WEIGHTS AND DIMENSIONS; MANAGEMENT OF STEAM BOATS; GENERAL HINTS ON MANAGEMENT, BOARDING, BOAT-CRUISING, &c., &c. Particulars of Steam Boats supplied to H.M. Navy. The details given may be taken as types of the different classes, though of course subject to slight variations. The hoisting weight of a 37 feet Pinnace with steam up, water tanks, coal boxes, &c., full, is 139 cwt. The Pinnaces and Cutters have sufficient buoyancy to float engines, coals, and crew, in event of being filled by a sea. P |