Understanding Ship Draft
Jan 16, 2026



Ship draft is the vertical distance between the waterline and the lowest point of a vessel’s hull, usually the keel. It indicates how deep a ship sits in the water and is a critical factor in safe navigation. Draft changes depending on the vessel’s load, including cargo, fuel, ballast, fresh water, and provisions. A deeper draft means the ship is heavier, while a lighter ship has a shallower draft. Understanding draft is essential when entering shallow ports, canals, rivers, or during berthing, as insufficient water depth can lead to grounding and structural damage.

There are different types of draft. Forward draft is measured at the bow, aft draft at the stern, and mean draft is the average of both. These measurements help officers assess trim, stability, and compliance with port restrictions. Draft also affects a ship’s speed, fuel consumption, and maneuverability, making accurate monitoring vital for efficient operations.

How to Read a Ship Draft

Ship draft is read using draft marks painted on the hull at the bow, stern, and sometimes midship. These marks are usually in meters or feet, with numbers increasing downward. To read the draft, observe the water level against the marks and note the number at the waterline. For greater accuracy, readings should be taken on both port and starboard sides and averaged, especially in rough or uneven water conditions.

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SECURITY LEVELS: ISPS CODE

The International Ship and Port Facility Security (ISPS) Code is a comprehensive set of measures adopted by the International Maritime Organization (IMO) under the Safety of Life at Sea (SOLAS) Convention. Established in response to heightened concerns about maritime terrorism and unlawful acts after the September 11, 2001 attacks, the ISPS Code entered into force on July 1, 2004. Its primary objective is to enhance the security of ships and port facilities by establishing a standardized, consistent framework that enables governments, shipping companies, port authorities, and other stakeholders to collaborate in identifying and addressing threats to maritime security. The ISPS Code is divided into two main parts. Part A is mandatory and lays down detailed requirements for governments, shipowners, and port facilities to follow. Part B contains recommended guidelines that provide flexibility in implementation but are not legally binding. Together, these parts form a comprehensive approach to maritime security, balancing strict compliance with adaptable measures tailored to specific risks and operational environments. Since its inception, the ISPS Code has been continuously updated to address evolving threats, including cyber risks, piracy, and organized crime affecting global trade routes. The Code applies to ships engaged in international voyages, including passenger ships, cargo ships of 500 gross tonnage and above, mobile offshore drilling units, and port facilities serving such ships. Each ship must have an approved Ship Security Plan (SSP) and designate a Ship Security Officer (SSO). Similarly, each port facility must maintain a Port Facility Security Plan (PFSP) and appoint a Port Facility Security Officer (PFSO). These officers are responsible for ensuring that security measures are implemented, drills and exercises are conducted, and compliance is maintained under the oversight of the Designated Authority from the flag or port state. A crucial feature of the ISPS Code is the establishment of three security levels, which provide a flexible and responsive framework to adapt to varying threat environments. Security Level 1 represents the normal condition, where minimum security measures must be maintained at all times. Security Level 2 is applied when there is an increased risk of a security incident, requiring additional protective measures. Security Level 3 represents the highest alert level, where a probable or imminent security threat exists, and extraordinary measures must be implemented to safeguard ships and port facilities. These security levels are set by the Contracting Governments and communicated to ships and port facilities. Ships are required to comply with the security level set by the administration of the port state they are visiting. This ensures that all parties are synchronized in their efforts, minimizing the likelihood of confusion or lapses during periods of heightened alert. The dynamic application of security levels demonstrates the adaptability of the ISPS Code to different threat scenarios, from routine operations to emergency conditions. Another critical element of the ISPS Code is the use of security assessments and plans. A Ship Security Assessment (SSA) identifies potential vulnerabilities, while the Ship Security Plan outlines the preventive, protective, and response measures to address them. Likewise, Port Facility Security Assessments (PFSA) and Plans detail site-specific risks and countermeasures. Both ships and port facilities undergo audits and verifications to ensure that these plans remain effective and updated, considering new threats such as cyberattacks targeting navigation and cargo systems. The ISPS Code also emphasizes international cooperation and information exchange. Contracting Governments are encouraged to share intelligence regarding potential threats, suspicious activities, and lessons learned from incidents. This collaborative approach enhances global maritime security, ensuring that vulnerabilities in one region do not compromise the safety of the wider international shipping community. The Code highlights that maritime security is not only a national concern but a shared global responsibility. Training and drills form an essential part of the Code’s framework. Crew members, ship officers, and port facility staff must undergo regular security training to familiarize themselves with procedures for access control, cargo inspections, restricted area monitoring, and emergency responses. Periodic drills test the readiness of personnel and the effectiveness of the security systems in place. These practices ensure that in times of real threats, the response is swift, coordinated, and efficient. Over time, the ISPS Code has expanded its scope to address emerging challenges. The increasing reliance on digital technologies in maritime operations has introduced new risks, particularly in the form of cyber threats. Recognizing this, the

VHF Marine Radio Channels

This VHF Marine Radio Channels guide presents a clear and practical overview of how Very High Frequency (VHF) radio channels are organized and used in maritime communication. It is designed to help seafarers, maritime students, and industry professionals quickly understand the correct use of each channel in daily operations and emergency situations. At the center of the guide is Channel 16, the internationally recognized channel for distress, safety, and calling, highlighting its vital role in emergency alerts and initial contact between vessels and shore stations. The diagram groups channels according to their operational purpose, including search and rescue (SAR), ship-to-ship safety information, port operations, commercial vessel communications, professional fishing vessels, recreational vessels, and maritime safety organizations. It also identifies channels dedicated to Digital Selective Calling (DSC) and VHF repeaters, supporting efficient distress alerting and extended communication coverage. Color Coding Guide: • Blue channels – Designated for ship-to-shore communications • Red channels – Used primarily for ship-to-ship communications • Black channels – Suitable for both ship-to-shore and ship-to-ship communications Overall, this guide serves as a reliable reference for proper VHF radio use, reinforcing international maritime communication standards while promoting safety, clarity, and effective coordination at sea.

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.

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.

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