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.

JET CHISEL

A jet chisel (also called needle scaler) is a pneumatic tool made up of multiple thin steel rods (“needles”) that rapidly move back and forth when connected to compressed air. The vibration of the needles chips away rust, old paint, scale, and marine growth on metal surfaces. Think of it as “pangbaklas ng kalawang, pero industrial version.” Purpose: • Remove rust, corrosion, and scale from steel surfaces • Prepare metal before painting, welding, or coating • Clean areas where grinders and wire brushes can’t reach (corners, tight spots, edges) • Reduce manual scraping time and physical fatigue How to Use: 1. PPE First • Safety goggles / face shield • Ear protection (maingay ’yan) • Gloves • Mask (dust/rust particles) • Proper coverall 2. Check the Tool • Inspect air hose, connectors, and needles • Ensure air compressor pressure is within recommended range (usually 90 psi ± depending on tool) 3. Connect to Compressed Air • Attach hose firmly • Open the air valve gradually 4. Operate • Hold the tool with both hands • Press the needles gently against the surface — do not push too hard • Let the vibration do the work • Work in steady strokes 5. After Use • Shut off air supply • Clean and oil the needles to prevent rust • Store in dry location

Simple Maritime Terminology

Every seafarer must know the ship’s basic directions and parts the foundation of good seamanship. ‣ PROA – The bow or front of the ship ‣ POPA – The stern or back of the ship ‣ ESTRIBOR– Starboard side (right when facing forward) ‣ BABOR – Port side (left when facing forward) ‣ CUBIERTA – Deck or surface area of the ship ‣ PUENTE – Bridge or navigation area ‣ CASCO – Hull, the main body of the ship ‣ MÁSTIL – Mast, where antennas or lights are mounted ‣ TIMÓN – Rudder, used to steer the vessel ‣ ANCLA – Anchor, used to hold the ship in place

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.