## A guide book to the Local marine board examination. The ordinary examination. [With] The requisite elements from the Nautical almanac for 1865, for the exercises in Ainsley's Guide book, Volumen24 |

### Términos y frases comunes

A.M. at ship added ADDITIONAL altitude angle apparent called central line characteristic chart chronometer column compass course Constant corr correct magnetic bearing corresponding cosine curve cyphers decimal decl declination departure deviation diff difference direction dist distance Distant Object Divide East equal error EXAMINATION EXAMPLES feet figures given gives gives hour-angle greater Green Greenwich half height of eye high water hundred index correction interval January July June latitude less logarithms longitude magnetic course March marked MATE mean meridian method miles minutes Multiply needle noon North observed observed altitude parallel pole Port position quotient Raper remainder result Rule sailing ship ship's head showed sine slow South Standard Compass steered subtracted supposing Table taken thousand tide variation West

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Página 59 - The Logarithm of a number to a given base is the index of the power to which the base must be raised to give the number. Thus if m = a", x is called the logarithm of m to the base a.

Página 2 - He must understand the use of the sextant, and be able to observe with it, and read off the arc. In SEAMANSHIP. — He must give satisfactory answers as to the rigging and unrigging of ships, stowing of holds, &c. ; must understand the measurement of the log-line, glass, and lead-line ; be conversant with the rule of the road, as regards both steamers and sailing vessels, and the lights carried by them.

Página 39 - PROOF. — Multiply the divisor by the quotient, and to the product add the remainder, if any.

Página 146 - ... upon so long as she remains upright. Besides the ordinary deviation of the compass there is a deviation caused by the heeling of iron ships, which may increase or decrease the deviation observed when the ship is upright. Cases have been observed in which the deviation from heeling has amounted to as much as two degrees for each degree of heel of the ship, that is, without altering the real direction of the ship's head, the apparent alteration in direction has amounted to 40° by heeling the ship...

Página 229 - AVhen this time is exactly one of the instants for which the required quantity is put down in the Ephemeris, nothing more is necessary than to transcribe the quantity as there put down. But when, as is mostly the case, the time falls between two of the times in the Ephemeris, we must obtain the required quantity by interpolation. To facilitate this interpolation, the Ephemeris contains the rate of change, or difference of each of the quantities in some unit of time.

Página 378 - Compass to make the following courses, correct magnetic. 9. Supposing you have steered the following courses by the Standard Compass, find the correct magnetic courses made from the above deviation table.

Página 103 - The COURSE steered is the angle between the meridian and the ship's head. The course made good is the angle between the meridian and the ship's real track on the surface of the sphere. The course is reckoned from the north, towards the east or west, when the ship's Ivead is less than eight points from the north point. The same applies to the south point. The course is measured in points of 11° 15' each, or in degrees and minutes.

Página 2 - Testimonials of character, and of sobriety, experience, ability, and good conduct on board ship, will be required of all applicants, and without producing them no person will be examined. As such testimonials...

Página 386 - To be added when the greater reading is off the arc, and subtracted when the greater reading is on the arc. 14.

Página 378 - With the deviation as above, give the courses you would steer by the Standard Compass to make the following courses, correct magnetic : — . . 9.