Double hull oil tanker is a
ship which is constructed primarily for the carriage of oil in bulk,
which have the cargo tanks protected by a double hull which extends
for the entire length of the cargo area, consisting of double sides
and double bottom spaces for the carriage of water ballast or void
A ballast tank is a tank which
is used solely for water ballast.
Overall survey is a survey
intended to report on the overall condition of the hull structure
and determine the extent of additional close-up surveys.
Close-up survey is a survey
where the details of structural components are within the close visual
inspection range of the surveyor, i.e. preferably within reach of
Transverse section includes
all longitudinal members such as plating, longitudinals and girders
at the deck, sides, bottom, inner bottom and longitudinal bulkheads.
Representative tanks are those
which are expected to reflect the condition of other tanks of similar
type and service and with similar corrosion protection systems. When
selecting representative tanks account should be taken of the service
and repair history onboard and identifiable critical and/or suspect
Suspect areas are locations
showing Substantial Corrosion and/or are considered by the surveyor
to be prone to rapid wastage.
Substantial corrosion is an
extent of corrosion such that assessment of corrosion pattern indicates
a wastage in excess of 75% of allowable margins, but within acceptable
Corrosion prevention system is
normally considered either:
Protective coating should usually be epoxy coating or equivalent.
Other coating systems may be considered acceptable as alternatives
provided that they are applied and maintained in compliance with the
Where soft coatings have
been applied, safe access should be provided for the surveyor to verify
the effectiveness of the coating and to carry out an assessment of
the condition of internal structures which may include spot removal
of the coating. When safe access cannot be provided, the soft coating
should be removed.
Coating condition is defined
|condition with only minor spot
|condition with local breakdown of
coating at edges of stiffeners and weld connections and/or light rusting
over 20% or more of areas under consideration, but less than as defined
for POOR condition,
|condition with general breakdown of
coating over 20% or more of areas or hard scale at 10% or more of areas
Critical structural areas are
locations which have been identified from calculations to require
monitoring or from the service history of the subject ship or from
similar or sister ships to be sensitive to cracking, buckling or corrosion
which would impair the structural integrity of the ship.
Cargo area is an area as defined
in regulation II-2/3.6 of the 1974 SOLAS Convention, as amended.
Intermediate survey is a survey
carried out either at the second or the third annual survey or between
A prompt and thorough repair is
a permanent repair completed at the time of survey to the satisfaction
of the Surveyor, therein removing the need for the imposition of any
associated condition of classification or recommendation.
Specially considered means
sufficient close-up inspection and thickness measurements are taken
to confirm the actual average condition of the structure under coating.