Understanding IMO Safety Symbols

The International Maritime Organization (IMO) safety symbols serve as universal visual guides designed to protect lives at sea. These standardized icons provide quick, clear, and language-independent instructions that help seafarers, passengers, and maritime professionals respond effectively in emergencies. Importance of Symbols on Board Onboard a vessel, safety depends not only on equipment but also on awareness. In critical situations where every second counts, IMO safety symbols minimize confusion by pointing directly to lifesaving appliances, emergency exits, fire control stations, and medical facilities. These symbols ensure that regardless of nationality or spoken language, crew and passengers can understand and act immediately. Categories of Safety Symbols The chart features a wide range of icons: • Lifesaving Equipment: Symbols for lifeboats, liferafts, rescue boats, lifejackets, immersion suits, and survival radios guide seafarers to crucial survival gear. • Emergency Actions: Icons such as eyewash, emergency stop buttons, stretchers, showers, and assembly points highlight essential emergency responses. • Evacuation Guidance: Running man symbols, arrows, escape ladders, and push-to-open signs direct safe movement during evacuation. • Communication & Fire Safety: Telephone stations, fire alarms, and firefighting systems are also clearly indicated

IMMERSION SUIT: Essential Survival Gear for Every Seafarer

An immersion suit also called a survival suit is a life-saving garment designed to keep seafarers protected in the event of abandoning ship, especially in cold waters. Made of insulated, waterproof material, it drastically slows body heat loss and increases chances of rescue. Purpose • Thermal Protection: Retains body heat to prevent hypothermia. • Buoyancy: Keeps the wearer afloat without the need to swim. • Visibility: High-visibility color and reflective tape help rescuers locate survivors quickly. • Survivability: Protects against wind, waves, and freezing temperatures while awaiting rescue.

2-Stroke Marine Diesel Engine

2- STROKE MARINE DIESEL ENGINE A 2-stroke marine diesel engine is a type of internal combustion engine that completes all four stages of operation intake, compression, combustion, and exhaust in two piston strokes (one crankshaft revolution). It is primarily used in large ships such as tankers, container vessels, and bulk carriers because of its high power output, fuel efficiency, and ability to run continuously for long periods. The engine is designed to deliver maximum torque at low revolutions per minute (RPM), making it ideal for direct propulsion of heavy marine vessels. Purpose The main purpose of a 2-stroke marine diesel engine is to generate continuous propulsion power for ships during long-distance voyages. It provides high torque and efficiency at low speed, enabling vessels to move massive loads across oceans while minimizing fuel consumption. Its robust design, long service life, and ability to operate on different fuel types from heavy fuel oil (HFO) to marine diesel oil (MDO) make it the backbone of commercial marine propulsion. Background and History The concept of the 2-stroke engine emerged in the late 19th century, pioneered by Dugald Clerk (1878) and Joseph Day (1891). In the early 20th century, diesel technology replaced steam propulsion as shipping demanded greater efficiency. By the 1930s, manufacturers like Sulzer, MAN B&W, and Mitsubishi developed large-scale crosshead-type 2-stroke engines, setting the standard for ocean-going ships. Since the 1960s, these engines have dominated maritime transport, evolving to meet stricter emission and fuel efficiency standards. Main Components and Functions • Cylinder Liner : Forms the combustion chamber’s wall and withstands high pressure and temperature. • Piston & Rings : Convert combustion energy to motion and maintain sealing between piston and liner. • Connecting Rod & Crankshaft : Transfer and convert linear motion into rotary motion for propulsion. • Crosshead Bearing : Separates the piston and connecting rod to prevent side forces. • Scavenge Air System : Supplies fresh air for combustion and removes exhaust gases. • Turbocharger : Utilizes exhaust gas energy to compress intake air for better combustion. • Fuel Injector : Sprays atomized fuel into the combustion chamber for ignition. • Exhaust Valve : Opens to release burnt gases. • Cooling and Lubrication Systems : Control temperature and minimize wear.

The Four Pillars of the International Maritime Organization (IMO)

The International Maritime Organization (IMO) establishes global standards to promote safety, protect the marine environment, ensure proper training of seafarers, and safeguard their welfare. These standards are anchored on four key conventions known as the 4 Pillars of IMO: 1. SOLAS – Safety of Life at Sea (1974) SOLAS is considered the most important international treaty concerning maritime safety. It sets the minimum standards for the construction, equipment, and operation of ships to ensure they are safe for both crew and passengers. This includes: • Fire protection systems • Life-saving appliances • Navigation and communication requirements • Emergency preparedness Its ultimate purpose is to prevent loss of lives at sea. 2. MARPOL – Marine Pollution (1973/1978) MARPOL addresses the prevention of pollution from ships. It regulates: • Oil and chemical spills • Sewage and garbage discharge • Air emissions from ships Its goal is to protect the marine and coastal environment by minimizing pollution from ship operations and accidents. 3. STCW – Standards of Training, Certification, and Watchkeeping for Seafarers (1978) STCW sets global training and competency standards for seafarers working on commercial vessels. It ensures: • Seafarers are properly trained, qualified, and certified • Uniform watchkeeping and operational safety practices across the world This helps maintain a high level of professionalism and safety at sea. 4. MLC – Maritime Labour Convention (2006) The MLC is often called the “Seafarers’ Bill of Rights.” It ensures that seafarers have: • Fair wages and employment contracts • Safe working and living conditions • Adequate rest hours • Medical care, social protection, and welfare The convention promotes human rights and dignity for those working at sea.