A tanker designed to carry refined petroleum products in bulk.

Related Terms


Ship Inspection Report - the risk assessment program developed by OCIMF, under which tankers are inspected and the results made available to potential charterers through a database of records.


Centrifugal cargo pumps used, differ according to the type of cargo e.g. product tankers (crude oil, etc) would have a separate pump room with conventional centrifugal pumps, probably vertical overhung impeller, sometimes called barrel-type cargo pump installed. This double eye inlet pump with either a straight-through or 90° suction-discharge angle with pipe connections in the bottom half of casing has two external bearings above the impeller, the upper one takes all the hydraulic thrust and the lower acts as radial load-bearing. This pump has certain advantages over its counterparts, namely:

  1. Impeller can be sited lower in the pump room thus improving suction conditions and reducing stripping time.
  2. Removal of impeller without disturbing pipe joints.
  3. Easier access to bearings and shaft seal without removal of rotating elements.

Chemical, LPG or multi-product tankers: Here a separate pump is sited in each tank. Pumps driven through line shafting coupled to hydraulic motors on deck will be deep well, single or multi-stage with radial or mixed flow impellers respectively. Or, submerged pumps electrically or hydraulically driven with, usually, single elements. The line-shaft pump, despite some bearing problems is proving the more popular, especially for LPG carriers. Submersible pumps eliminate line shaft bearings and gland problems but expensive problems could occur due to hydraulic fluid leakage into the cargo and vice-versa.


Inert Gas System - a system that introduces a blanket of non-explosive or inert gas on top of cargo in a tank usually consisting of burned stack gases which are low in oxygen.
With an inert gas system, a tank is protected from exploding by introducing inert gas into it to keep the oxygen content low and to reduce to safe proportions the hydrocarbon gas concentration of its atmosphere.

Ship's IGS installation usually consists of:

  • Burner and combustion chamber
  • Oxygen Analyzer
  • Main and Aux. Blower (It is necessary to deliver the gas through the deck water seal, the non-return valve and the deck isolating valve to the cargo tanks)
  • Scrubber (It is necessary to cool and cleaning the exhaust gas from AB)
  • Deck Water Seal and Non-return valves (Are necessary for prevents backflow of cargo gases from the cargo tanks to the machinery spaces)
  • P/V Breaker (It prevents the damage of cargo tanks from high or vacuum pressure in cargo tanks)
  • pipes and valves and P/V valves
  • gas pressure regulating valve is fitted downstream of the blowers to regulate the flow of gases to the cargo tank
  • Mast Riser (It is necessary for quick relief of inert gas the pressure in cargo tanks)


A CLC Certificate is a document issued by the flag state to evidence insurance coverage or other financial security for Civil Liability arising out of oil pollution damage. Applies to tankers and indicates compliance with CLC Convention. The certificate valid for a year and expires on the 28th of February each year.


A pump designed to increase the pressure in the pipeline during the unloading process. It is installed on the cargo deck of the tanker and is connected in series with the main cargo pumps.


Code for the Construction and Equipment of Ship Carrying Dangerous Chemicals in Bulk. It is applied to chemical tankers built before 1986, as well as to converted and combined tankers.


A tank in a tanker into which the residue of tank washing are pumped.


Ultra large crude carriers larger than 300,000dwt.


A removal of all traces of a cargo from the tanks of a tanker normally by means of high pressure water jets.


An association of independent tanker owners whose aims are to represent the views of its members internationally.

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