DICTIONARY OF

Centre of Percussion 75 Certificate of Seaworthiness
Centre of Percussion. That point, in a striking mass, at which the whole force of the blow
would cause no jar. In case of a bar of uniform density, revolving around one end, would be
2/3rds distant from centre of revolution.
Centre through Plate. Continuous girder going fore and aft along centre of bottom of a
steel ship. Floors are attached to it on opposite sides.
Centrifugal Pump. Pump in which liquid is withdrawn by giving it a high rotational speed
and allowing it to escape tangentially. Suction is provided by a partial vacuum caused by
escaping liquid.
Cepheids. Short period variable stars whose magnitudes vary in the course of a few days.
Rigel, Canopus, Antares are examples.
Cepheid Variables. 'Cepheids.' Particularly notable in constellation Cepheus.
Cepheus. Northern constellation situated between Cassiopeia and Andromeda. In Greek
mythology, Cepheus was father of Andromeda and husband of Cassiopeia.
Ceres. First of the asteroids to be discovered.
Certificated Cook. Ship's cook who holds a certificate granted by D.T.I, or an approved
cookery school. Ships of 1000 tons gross and upward must carry a certificated cook.
Certificated Lifeboatman. Seaman, who has passed through a course in work connected
with ship's lifeboats, and has received a certificate of efficiency.
Certificated Officer. Officer holding a Certificate of Competency issued by the
Department of Trade and Industry.
Certificate of Clearance. Issued to master of emigrant ship, by emigration officer, when
the latter is satisfied that ship is sea worthy, in safe trim, fit for intended voyage, that
steerage passengers and crew are fit in health, that master's bond has been fully executed.
Certificate of Competency. Certificate issued by D.T.I, to a seaman or officer who has
passed an examination in a specified grade, and has been found fit to perform the duties of
the grade.
Certificate of Freeboard. International certificate, issued by an 'Assigning Authority',
detailing minimum permissible freeboards in stated areas at specified seasons. Often called
'Load Line Certificate'.
Certificate of Grain. 'Grain Certificate.'
Certificate of Pratique. Certificate issued by medical officer of port to an arrived ship
when he is satisfied that health of crew is satisfactory. Prerequisite to 'Entry Inwards'.
Certificate of Registry. A vessel's identity certificate. Issued by the Government of a
country, through assigning authorities, after vessel has been surveyed. Gives relevant
particulars, rig, dimensions, tonnage, machinery, etc., and name/s of owner/s. Master's name
is endorsed on it at each change of appointment.
Certificate of Seaworthiness. Certificate granted by a surveyor, or Court of Survey, when
the seaworthiness of the vessel may be open to question, and after she had been examined
and found seaworthy.