Maritime Zones Explained: The Boundaries of Our Seas
Nov 25, 2025



The concept of maritime zones is a cornerstone of international maritime law, defined primarily by the United Nations Convention on the Law of the Sea (UNCLOS). These zones determine the extent of a coastal state’s rights, responsibilities, and jurisdiction over the waters and resources adjacent to its shores.

Background
• Maritime zones were established to resolve disputes over navigation, resource ownership, and national security.
• Boundaries are measured from a country’s baseline (usually the low-water mark along the coast).
• The key zones include:
• Internal Waters – full sovereignty like land territory.
• Territorial Sea – up to 12 nautical miles.
• Contiguous Zone – up to 24 nautical miles.
• Exclusive Economic Zone (EEZ) – up to 200 nautical miles.
• Continental Shelf – may extend beyond 200 nautical miles depending on natural features.

Purpose
• Internal Waters – treated like land territory, full state control.
• Territorial Sea (12 nm) – authority over navigation, resources, and law enforcement.
• Contiguous Zone (24 nm) – enforcement against smuggling, illegal entry, and security threats.
• Exclusive Economic Zone (200 nm) – exclusive rights to explore and exploit resources (fish, oil, gas).
• Continental Shelf – rights over seabed resources even beyond EEZ.

Importance
• Safeguards national security and territorial sovereignty.
• Ensures sustainable use of marine resources (fisheries, oil, gas).
• Provides control over shipping routes and trade lifelines.
• Strengthens sovereignty in disputed waters (vital for nations like the Philippines).
• Globally, reduces conflict, promotes order and cooperation, and protects the marine environment.

ADVERTISEMENT

RELATED EDUCATIONAL VIEW MORE...

Central Cooling System

Central Cooling System (CCS) on Ships The Central Cooling System (CCS) is the primary method used on modern vessels to maintain safe operating temperatures for engines and auxiliary machinery. Instead of relying on multiple separate cooling circuits, a CCS uses a single freshwater loop to cool major equipment. This freshwater absorbs heat from engines and machinery and then transfers that heat to seawater through a central cooler. By using freshwater internally and seawater externally, the system offers both efficiency and protection for vital components. Purpose of the Central Cooling System The CCS is designed to provide a stable and controlled cooling environment for the ship’s mechanical systems. Its main purposes include: •Preventing Overheating: Engines, compressors, generators, and pumps produce significant heat during operation. The CCS ensures they remain within safe temperature ranges. •Reducing Corrosion: Freshwater circulates inside machinery rather than corrosive seawater, greatly extending equipment lifespan. •Improving Efficiency: Consistent cooling improves fuel efficiency, power output, and overall engine performance •Simplifying Maintenance: A centralized system requires fewer individual coolers, making inspection and repairs easier and more cost-effective. •Environmental and Safety Protection: Proper cooling prevents machinery failures that could lead to pollution, downtime, or emergency situations. A Brief History of Marine Cooling Systems Early ships relied on direct seawater cooling, where seawater passed directly through engines. While simple, this system caused rapid corrosion, fouling, and frequent breakdowns. As engine outputs increased with advancements in marine propulsion, a more reliable and controlled method became necessary. By the mid- 20th century, ships shifted toward a jacket-water (freshwater) cooling system, where freshwater circulated around the engine block. However, many small coolers were still used for individual machinery, creating complexity. The modern Central Cooling System emerged as a solution: •One freshwater loop for all machinery •One central cooler to transfer heat to seawater •Better temperature control and lower maintenance Today, the CCS is standard on most commercial vessels due to its efficiency and durability.

4- Stroke Engine

The Four-Stroke Engine The four-stroke engine is one of the most important innovations in mechanical and marine engineering. Known for its reliability and efficiency, this internal-combustion engine powers ships, vehicles, and generators across the world. Each cycle of this engine goes through four distinct strokes — intake, compression, power, and exhaust — that convert fuel into mechanical energy efficiently and cleanly. A Brief History The concept of the four-stroke cycle was first proposed in 1862 by French engineer Alphonse Beau de Rochas, who described how an engine could work more efficiently by separating the intake, compression, power, and exhaust processes. This theory was brought to life in 1876 by German engineer Nikolaus August Otto, whose engine design became known as the “Otto Cycle.” His invention marked the foundation of modern engines, influencing both automotive and marine propulsion systems.

Understanding Echo Sounder

An echo sounder is an essential marine instrument that measures the depth of water beneath a vessel by utilizing sound waves. It operates on the principle of sonar (Sound Navigation and Ranging), where sound pulses are emitted into the water and their echoes are analyzed upon return. This technology has been a cornerstone in maritime navigation and research for decades . Operational Mechanism The echo sounder system comprises several key components that work in a sequence: 1. Display Unit: Serves as the interface for the operator, showing real-time data and system status. 2. Pulse Generator: Generates electrical signals that define the characteristics of the sound pulses. 3. Transmitter: Amplifies the electrical signals and sends them to the transducer. 4. Transducer: Converts electrical signals into sound waves and emits them into the water. 5. Propagation Medium (Water): The sound waves travel through the water column until they encounter an object or the seabed. 6. Echo Reception: Reflected sound waves (echoes) return to the transducer, which converts them back into electrical signals.  7. Receiver and Amplifier: Processes and strengthens the returned signals for analysis.  8. Display Unit: Presents the processed data, indicating depth readings and potential underwater objects. The time interval between the emission of the sound pulse and the reception of its echo is used to calculate the distance to the reflecting object, typically the seabed. This calculation considers the speed of sound in water, which averages around 1,500 meters per second . Importance of Echo Sounders Echo sounders play a pivotal role in various maritime activities: • Navigation Safety: By providing accurate depth measurements, they help prevent groundings and collisions with submerged hazards. • Fishing Industry: Aid in locating fish schools and understanding seabed topography, enhancing fishing efficiency. • Hydrographic Surveys: Essential for mapping the seafloor, which is crucial for charting and marine construction projects. • Scientific Research: Utilized in oceanography for studying underwater geological formations and marine life distributions. • Submarine and Military Operations: Assist in underwater navigation and detecting other vessels or obstacles. Echo sounders have evolved significantly, with modern systems offering high-resolution imaging and integration with other navigational tools. Their ability to provide real-time, accurate underwater information makes them indispensable in the maritime domain.

UNCLOS WATERS

The United Nations Convention on the Law of the Sea (UNCLOS) stands as one of the most important international agreements in maritime history, providing a comprehensive framework that governs the rights, responsibilities, and conduct of nations in their use of the world’s oceans. Adopted in 1982 in Montego Bay, Jamaica, and entered into force in 1994, UNCLOS has since become the “constitution of the oceans,” shaping the global maritime order and ensuring stability in international waters. Today, more than 160 countries, including the Philippines, are parties to this convention, making it one of the most widely recognized treaties in modern international law. At its core, UNCLOS defines the extent of maritime zones, granting coastal states sovereign rights and jurisdiction over certain areas of the seas while maintaining the principle of freedom of navigation. The convention establishes baseline measurements from which maritime zones are determined, ranging from internal waters, territorial seas, and contiguous zones, to exclusive economic zones (EEZs) and continental shelves. These zones outline the rights of coastal states to exploit resources, regulate activities, and protect their environment, while balancing the rights of other states to access international waters. The territorial sea, extending up to 12 nautical miles from the baseline, grants full sovereignty to coastal states, similar to their land territory, albeit with the obligation to allow innocent passage for foreign vessels. Beyond this lies the contiguous zone, extending up to 24 nautical miles, where states can enforce customs, fiscal, and immigration regulations. However, it is the 200-nautical-mile Exclusive Economic Zone that has arguably had the most profound impact, as it allows coastal states exclusive rights to exploit and manage natural resources, including fisheries and energy reserves. UNCLOS also addresses the rights of landlocked states by ensuring access to the seas through transit routes and cooperation with neighboring states. By codifying these provisions, the convention promotes equity among nations and prevents maritime access from becoming a privilege limited only to coastal countries. Furthermore, it establishes rules on the exploitation of the deep seabed beyond national jurisdiction, declaring it the “common heritage of mankind” and mandating that its resources be managed for the benefit of all humanity. An important element of UNCLOS is its contribution to environmental protection. The convention obligates states to prevent, reduce, and control pollution of the marine environment, whether from ships, land-based sources, or dumping. It also encourages cooperation in scientific research, preservation of rare ecosystems, and sustainable use of marine living resources. These provisions reflect the recognition that the oceans are interconnected and that environmental harm in one region can have ripple effects across the globe. UNCLOS has also proven essential in resolving disputes among states. It provides mechanisms for peaceful settlement through negotiation, arbitration, or adjudication by bodies such as the International Tribunal for the Law of the Sea (ITLOS). These mechanisms ensure that maritime disputes, whether over boundary delimitations or navigational rights, are settled according to international law rather than unilateral action or force, thereby reducing the risk of conflict. The convention further enshrines the principle of freedom of navigation and overflight, vital for global trade and security. Given that around 90% of world trade is transported by sea, these provisions protect the lifeblood of the global economy. Naval operations, commercial shipping, and international aviation all rely on the stability and predictability created by UNCLOS, underscoring its role not only as a legal framework but also as a safeguard of global commerce. Over time, UNCLOS has adapted to contemporary challenges. Issues such as maritime security, piracy, illegal fishing, and marine biodiversity beyond national jurisdiction have required new interpretations and agreements supplementary to the convention. Despite criticisms that it cannot fully address emerging issues like climate change and rising sea levels, its framework remains the backbone of modern maritime governance. For countries like the Philippines, UNCLOS is particularly significant, as it provides the legal basis for asserting rights over maritime zones and resources. The 2016 arbitral ruling on the South China Sea dispute, rooted in UNCLOS provisions, reinforced the importance of the convention as a peaceful tool for resolving maritime conflicts, affirming that international law remains the strongest shield of smaller states against larger powers. In sum, UNCLOS has become indispensable in maintaining order in the world’s oceans. It balances the interests of coastal and landlocked states, safeguards navigation rights, promot

MARINO PH - The largest maritime community.
9_20250904_175149_0008.png
10_20250904_175149_0009.png
12_20250904_175150_0011.png
19_20250904_175150_0018.png
20_20250904_175150_0019.png
23_20250904_175150_0022.png
26_20250904_175150_0025.png
32_20250904_175150_0031.png
5_20250904_175149_0004.png
6_20250904_175149_0005.png
8_20250904_175149_0007.png
11_20250904_175149_0010.png
13_20250904_175150_0012.png
14_20250904_175150_0013.png
15_20250904_175150_0014.png
16_20250904_175150_0015.png
17_20250904_175150_0016.png
18_20250904_175150_0017.png
21_20250904_175150_0020.png
22_20250904_175150_0021.png
24_20250904_175150_0023.png
25_20250904_175150_0024.png
27_20250904_175150_0026.png
28_20250904_175150_0027.png
29_20250904_175150_0028.png
30_20250904_175150_0029.png
31_20250904_175150_0030.png
33_20250904_175150_0032.png

Marino PH Logo

MARINO PH

The largest maritime community in the Philippines
© 2025 All Rights Reserved.


CONTACT INFORMATION

+63 (02) 8743 5810
customercare@marinoph.com
Agoncillo Building, 1580 Taft Ave, Ermita, Manila City, 1000 Metro Manila