8 Differences Between A Ship & A Boat

What’s the Difference Between a Ship and a Boat?

The simplest difference between a ship and a boat is that the former can accommodate the latter but not vice versa.

Though both might look similar, they both are actually on opposite ends of the classification, as a ship is subject to IMO conventions, flag state inspections, and has a STCW-certified crew, while a boat does not need to meet any such requirements.

Even if we set aside the size factor, a ship has to meet certain tonnage and design benchmarks, have an operational range and possess a command structure where the captain is at the helm and whose decisions are final.

For anyone working in or studying the maritime industry, understanding these differences between a ship and a boat is very important.

Ship Vs Boat- A Quick Comparison

Feature	Ship	Boat
Size	Typically 200ft (60m) or longer	Generally under 100ft (30m)
Gross tonnage	Usually 500 GT or above	Below 500 GT
Crew	Large, permanent, STCW-certified	Small, crewed only when in use
Navigation range	Ocean-going, deep-water	Coastal, inland, limited range
Propulsion	Multi-engine, dedicated engine room	Single outboard or inboard engine
Cargo/passenger capacity	Thousands of TEUs or passengers	Limited — recreational or small-scale
Regulatory framework	IMO conventions, flag state, and PSC inspections	National maritime authority only
Cost	$50 million to over $1 billion	$10,000 to $500,000

1. Size and Tonnage

While size, perceived through the eyes, is the most visible and commonly cited difference between a ship and a boat, there is a technical term in maritime called Gross Tonnage, i.e., it is a volumetric measure of a vessel’s enclosed space and not physical weight.

Vessels having a gross tonnage of 500 and above are called ships, per SOLAS and MLC 2006, while those weighing less than that are called boats.

Ships are also subject to strict regulatory requirements, unlike boats. Most ships are massive in size and weigh a lot. Rarely will you find any ship which is less than 60 m long.

The container ship Ever Given, which came into the limelight for blocking the Suez Canal in 2021, was 400 m long and had a displacement of 220,000 GT.

On the other hand, boats are under 100 feet in length and can be of different types, such as a fishing vessel or a recreational cruiser.

While there are no clear demarcation lines, the 500 GT is the standard in regulatory contexts.

2. Operational Range and Navigation

Ships can sail on open seas or oceans for weeks or months without needing to refuel, as their fuel capacity can exceed 5000 metric tonnes of heavy fuel oil. They also carry sufficient provisions, including food, drinking water and life-saving gear.

Boats usually operate in smaller water bodies like lakes, bays, lagoons, or rivers. They are also used for small-distance transport of goods and people in places where all-weather roads cannot be constructed.

Technically, a boat is not built to endure the harsh conditions of the oceans like saltwater, swells or tumultuous waves. They are small in size and hence can carry limited food, fuel and other resources, which means they cannot sail for months without coming to port.

The distinction is important under SOLAS, which lays down stringent requirements for ships regarding the presence of lifesaving gear onboard, fire protection measures and navigation systems to ensure the safety of crew members and the ship.

Boats come under the purview of a country’s maritime authority’s laws and regulations, which are relatively lighter.

3. Crew Requirements and Command Structure

A ship has a permanent crew that is well-qualified and possesses the necessary qualifications and certifications. They have designated duties onboard depending on the department they belong to. There is a deck department and an engine department.

The former has a Master/Captain, Chief Officer, Second Officer, and Third Officer, all of whom hold STCW certificates of competency. The engine department also mirrors this structure and has a chief engineer, a second engineer, etc.

Boats, in this sense, do not have a strict command structure comprising officers of different ranks. They do not have a watch schedule, and neither do they have permanent crew members, as they are crewed only when used.

A recreational sailing boat can be operated by a single person with a national coastal skipper licence. The presence of a permanent crew with a Master indicates that a vessel is a ship, irrespective of size.

4. Hull Design and Construction

Ships are classified by classification societies such as Lloyd’s Register, DNV, Bureau Veritas, and the American Bureau of Shipping, which certify that their hull design, onboard machinery, and other systems meet the international structural and safety requirements laid out by IMO.

Without class certification, a ship cannot get insurance or operate legally.

Certain types of ships have to meet more stringent requirements than others because they carry dangerous cargo, such as oil tankers.

According to MARPOL Annex I, tankers constructed after 2010 must have a double-hull, which comprises 2 steel layers separated by a void space to reduce the risk of an oil spill in the event of an accident, collision, or grounding.

Boats are usually built for customers according to their requirements, as per national standards, but they are not subject to the oversight of International Classification Societies.

The materials and construction methods used for both are also very different.

While a boat can be built in just a few days, in a small space, a ship’s construction occurs in stages in massive shipyards, followed by days or months of sea trials to ensure its seaworthiness.

5. Propulsion and Engine Systems

Ships run on slow-speed, two-stroke diesel engines which use heavy fuel oil (HFO), with output measured in megawatts.

However, many new constructions are also using cleaner alternatives like LNG and methanol to reduce the carbon footprint, and meet IMO’s 2020 sulphur regulations and the 2030 decarbonisation targets.

A ship’s engine room is managed by engineering officers, including a Chief Engineer, Second Engineer, and watchkeeping engineers who hold STCW engineering certificates.

Boats have a simple propulsion system, which includes an outboard motor, or, in the case of sailing vessels, wind-assisted propulsion with a backup engine.

6. Cargo and Passenger Capacity

A ship’s enormous carrying capacity is what makes global trade possible and lucrative. In one journey, they can carry thousands of tonnes of cargo from one part of the world to another.

The biggest container ships, which are currently operational, can accommodate over 24,000 twenty-foot equivalent units (TEUs).

A Panamax bulk carrier carries 65,000 to 80,000 deadweight tonnes of dry cargo, while the world’s biggest cruise ship, the Wonder of the Seas, is no less than a floating city since it welcomes 6,988 passengers and has a 2,300-member crew.

Boats have a smaller carrying capacity. For instance, a ferry crossing a harbour, a fishing trawler landing a catch or a recreational vessel with a family on vacation, represents the limited capacity of boats.

It is important to note that even commercial fishing vessels, even bigger ones, are generally classified as boats in common maritime usage unless they exceed the above-mentioned tonnage threshold.

7. Regulatory and Classification Frameworks

Ships are subject to a complex regulatory framework, and the International Maritime Organisation sets the conventions.

SOLAS governs safety, MARPOL governs pollution prevention, and MLC 2006 governs seafarer welfare.

These conventions are implemented and enforced by Flag States through their respective maritime authorities, and Port State Control Officers inspect ships in port to verify if they are compliant with these mandatory regulations.

If a ship is found to be non-compliant, for instance, if it does not have the minimum number of lifeboats required, or has an expired fire-fighting system or crew with expired certificates, etc., it can be detained in port until the matter is resolved.

Boats for domestic use fall under the purview of national maritime regulations, which means a simpler registration process, no port state control inspections and no stringent safety requirements.

8. Cost

Ships are costly to build and operate, and also require insurance. A Panamax container ship costs approximately $50 million to $80 million to build.

A Very Large Crude Carrier (VLCC) runs $100 million or more. The cruise ship, Wonder of the Seas, cost an estimated $2 billion!
A large container ship burns 150 to 200 metric tonnes of fuel per day.

Ships also have additional expenses comprising crew wages, maintenance costs, port dues, and classification society fees that run into millions of dollars.

Boats range from a $10,000 aluminium fishing vessel to a $500,000 luxury motor yacht. Their operational and regulatory compliance costs are less than those of ships.

The Submarine Exception

Submarines, including nuclear-powered vessels, are called boats, not ships.

The USS Ohio (SSBN-726), which is a nuclear ballistic missile submarine, displaces 18,750 tonnes when submerged, but the US Navy designates it a boat.

The tradition dates to a time when submarines were small enough to be carried aboard surface ships. The name was carried forward due to naval tradition, even though submarines evolved and came to rival ships in size.

Frequently Asked Questions

1. What is the simplest way to tell a ship from a boat?

A ship can carry a boat, but a boat cannot carry a ship. Additionally, if a vessel has a permanent crew with a Master, operates on open seas and is subject to IMO conventions, it is a ship.

2. At what size does a boat become a ship?

The technical threshold is 500 gross tonnage. Vessels at or above 500 GT are subject to international maritime conventions, including SOLAS and MLC 2006. However, there is no internationally agreed legal definition, and flag states may apply different criteria.

3. Why are submarines called boats and not ships?

The answer is Naval tradition. Early submarines were small enough to be carried aboard surface ships and so were called boats.
The name continued to be used even though submarines grew in size and capabilities.

4. Is a cruise ship a boat or a ship?

Even the smallest cruise vessels exceed 500 GT, have a licensed crew and are subject to SOLAS and MLC 2006. The Wonder of the Seas displaces approximately 236,857 GT and is one of the largest ships ever built.

5. What is the difference between a ship and a yacht?

A yacht is used for recreational or private purposes. Small yachts are boats, but bigger motor yachts over 500 GT, sometimes called superyachts, can be classified as ships and may be subject to commercial ship regulations if used for charter.

6. Can a fishing vessel be considered a ship?

Large commercial fishing vessels exceeding 500 GT are classified as ships, but smaller ones under 500 GT are referred to as boats.

Conclusion

Tonnage, operational range, crew structure, regulatory burden, and cost are some of the factors taken into account when classifying a vessel as a ship or a boat. Understanding this difference is crucial as frameworks governing a 200,000 GT tanker and a 50 GT coastal ferry are different in scope and consequence.

The 500 GT threshold and the presence of a permanent, STCW-certified crew are the most reliable indicators. The submarine, however, remains an exception due to the prevalence of naval tradition over technical classification.

You might also like to read-

• Types of Sailboats: A Comprehensive Classification
• A Guide to Different Types of Boats
• A Guide To Types of Ships
• Types of Fishing Vessels