Glossary: I

16 terms.

• Immersion Suit
  A watertight thermal protective suit worn in cold water abandonment that significantly extends survival time.
• IMO Number
  A unique seven-digit identifier assigned to a ship for life, used to track its history regardless of flag, owner, or name changes.
• Inert Gas System
  A system supplying inert gas (flue gas or nitrogen) to tanker cargo tanks to maintain an oxygen-deficient atmosphere and prevent explosion.
• Innocent Passage
  The right of foreign ships to navigate through a coastal state's territorial sea continuously and without prejudice to its peace or security.
• Inshore Traffic Zone
  The water between a traffic separation scheme and the adjacent coast, normally reserved for local and small craft traffic.
• Intercept
  In celestial navigation, the difference in minutes of arc between the observed altitude and the calculated altitude, used to plot a position line.
• Intermediate Fuel Oil
  A blend of heavy residual and distillate fuel oil with viscosity typically 180 or 380 cSt, used as main engine bunker.
• Intermediate Survey
  A classification survey conducted midway through the five-year special survey cycle, typically around the second or third year.
• International Association of Classification Societies
  A body of twelve major classification societies that collectively establish and promote uniform technical standards for ship construction and maintenance.
• International Convention for the Prevention of Pollution from Ships
  The main international convention covering prevention of pollution of the sea by ships from operational and accidental causes.
• International Convention for the Safety of Life at Sea
  The primary IMO convention setting minimum safety standards for ship construction, equipment, and operation.
• International Maritime Dangerous Goods Code
  IMO code governing the safe carriage of hazardous materials by sea, covering classification, packing, marking, and stowage.
• International Regulations for Preventing Collisions at Sea
  IMO rules prescribing conduct of vessels to prevent collisions, including lights, shapes, sound signals, and steering rules.
• International Safety Management Code
  IMO code requiring shipping companies to establish a Safety Management System to ensure safe ship operation and pollution prevention.
• International Ship and Port Facility Security Code
  IMO code mandating security plans, officers, and assessments for ships and port facilities to prevent terrorism and unlawful acts.
• Intertropical Convergence Zone
  A band of low pressure near the equator where trade winds converge, producing persistent convective weather and squalls.