DICTIONARY OF

to be carried in steamships of stated tonnages.
Manoeuvre. Regulated change of direction, position or speed to attain a desired end. 2. To
change direction, position or speed for a specific purpose.
Man-of-War. A warship.
Manometer. Instrument that measures pressure and elastic properties of gases. Barometer
and steam gauges are examples.
Man Overboard. 9 Call and report given when a person has been seen to fall into the sea
from a vessel.
Manropes. Protective ropes at side of a ladder or inclined wooden steps. Short ropes, used
when embarking or disembarking from, or into, boats from lower platform of
accommodation ladder; ropes being attached to stanchions on the platform.
Manrope Knot. Made in end of manrope to form standing part at eye of stanchion on
platform of accommodation ladder, or at a hatchway. Is a wall knot with crown above and all
parts followed round once.
Man Ship. Naval ceremony indicating compliment and, formerly, peaceful intentions. Crew
are spaced at regular intervals along sides of upper decks. 2. To provide a crew for a vessel.
Man Yards. Ceremonial disposition of crew of sailing ship. Men are placed at intervals on
all yards, standing on the yards and being steadied by jackstays stretched from mast to lift of
yard. Discontinued by R.N. in 1902, by order of King Edward VII.
Marconi Rig. Nickname for 'Bermuda Rig'.
Marcq St. Hilaire Method. Procedure for finding ship's position line from an observation
of a heavenly body and the calculation of the altitude and azimuth it would have if ship were
at estimated position. The difference between the calculated altitude (or zenith distance) and
observed altitude (or zenith distance) is the error in locus of assumed position line. The
position line is moved towards or away from the geographical position of the observed body
according to the amount the two altitudes (or zenith distances) differ.
Mareel. Shetland name for phosphorescence of the sea.
Maregraph Plongeur. Instrument for measuring changes in sea level by automatically
recording changes in pressure at sea bottom. Two Bourdon tubes are open to pressure and
mechanism records the resultant movements of their free ends.
Mare's Tails. Tufted cirrus clouds.
Margin of Safety Line. Line drawn parallel to bulkhead deck at side line, and three inches
below the upper surface of that deck at sides.
Margin Plate. Plating forming side of double-bottom ballast tank.