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

Fouling

Fouling in the Engine Room Fouling inside heat exchangers, piping and machinery is a persistent threat to vessel reliability, fuel efficiency and safety. Left unchecked, deposits and films build up on internal surfaces, reducing heat transfer, increasing pump and compressor loads, and accelerating corrosion. Below we explain the six common types of engine-room fouling, their root causes, operational impacts, and practical prevention measures every chief engineer and technical manager should know. Types of fouling 1. Scaling Mineral salts precipitate from hard water (e.g., calcium or magnesium salts) and form hard, insulating layers on heat-transfer surfaces. Scaling reduces thermal efficiency and flow, increasing fuel consumption and risking overheating of machinery. 2. Particulate fouling Suspended solids sand, rust particles, paint flakes or sediment settle and accumulate in piping and exchangers. These deposits obstruct flow paths and erode components, leading to frequent filter replacements, higher head loss and reduced system performance.

MARINE MAIN ENGINE

Marine Main Engine The marine main engine is the heart of a ship’s propulsion system. It is the largest and most powerful machine on board, designed to convert fuel into mechanical energy that turns the propeller and drives the vessel forward. Without it, modern shipping—responsible for carrying around 90% of the world’s trade—would not be possible. Understanding the main engine is essential for students, seafarers, and anyone interested in marine engineering. Meaning and Purpose The main engine refers to the primary source of propulsion power in a ship. Its purpose is straightforward yet vital: to provide continuous, reliable thrust to move the vessel safely across oceans. Unlike auxiliary engines, which generate electrical power for onboard systems, the main engine directly powers the propeller shaft. This distinction highlights its role as the core machinery that ensures a ship’s mobility and operational efficiency. Background Marine engines have evolved significantly since the early days of steam propulsion. In the 19th century, ships relied on coal-fired steam engines. Over time, these were replaced by more efficient internal combustion engines. Today, the most common propulsion system in large commercial vessels is the two-stroke low-speed diesel engine, valued for its efficiency, durability, and ability to burn heavy fuel oil. However, with increasing environmental regulations, new technologies and alternative fuels are reshaping the future of marine propulsion.

FIRE EXTINGUISHERS USED ON SHIPS

Fire extinguishers are essential first-response tools used to control and suppress different types of fires onboard ships. Each extinguisher is designed with a specific firefighting agent that targets certain classes of fire such as solid combustibles, flammable liquids, gases, metals, cooking oils, and even electrical sources. Onboard vessels, the correct selection and proper use of a fire extinguisher can prevent a small incident from escalating into a major emergency. Understanding the types, functions, and limitations of each extinguisher ensures safe and effective response by the crew. Types of Fire Extinguishers Dry Powder Fire Extinguisher This versatile extinguisher uses a fine powder that interrupts the chemical reaction of fire. It is considered an “all-rounder” because it can tackle multiple classes of fire, including flammable gases and electrical fires. Effective For: Class A, B, C, D, K/F, Electrical fires Best Use Onboard: Machinery spaces, engine rooms, areas with fuel, chemicals, and electrical equipment. Foam Fire Extinguisher Foam extinguishers work by forming a blanket over the burning surface, cooling the fire and preventing oxygen from reaching the fuel. Ideal for liquid-based fires. Effective For: Class A and B fires Best Use Onboard: Cargo areas, storerooms with paints/fuels, accommodation spaces. CO₂ (Carbon Dioxide) Fire Extinguisher This extinguisher releases high-pressure CO₂ gas that displaces oxygen, suffocating the fire without leaving any residue. Safe for electrical panels as it does not damage equipment. Effective For: Class B fires, Electrical fires Best Use Onboard: Control rooms, bridge equipment, engine control panels, electrical rooms. Water Fire Extinguisher Water extinguishers cool the burning material by reducing the temperature below ignition point. They are simple, effective, and environmentally friendly—but ONLY for solid combustible fires. Effective For: Class A fires Best Use Onboard: Storage areas with paper, wood, cloth, and other solid materials. Warning: Never use on electrical, fuel, or grease fires. Wet Chemical Fire Extinguisher This extinguisher is specifically designed to fight fires involving cooking oils and fats. It works by cooling and forming a chemical layer that prevents re-ignition making it vital for galley operations. Effective For: Class A and Class F/K fires Best Use Onboard: Ship galleys, cooking stations, and food preparation areas.