Why Do Ships Take Longer Routes?

Here are some common reasons for ships taking longer routes instead of shorter ones.

1. Weather Can Push Ships Away From the Shortest Route

Weather is one of the most important factors that cause ships to change course.

Strong winds, large waves, storms, hurricanes, and other severe conditions can make a direct route uncomfortable, inefficient, or unsafe.

Instead of sailing directly toward the destination, a vessel may move around a storm system.

For example:

Imagine a container ship traveling across the Atlantic.

A straight route may pass through an area where a major storm is developing. The captain or voyage planner may choose to travel farther north or south to avoid the worst conditions.

The vessel travels more miles, but the alternative route may reduce:

• Dangerous wave exposure
• Heavy wind resistance
• Vessel stress
• Fuel waste
• Risk of delays

The International Maritime Organization notes that weather routing accounts for wind, waves, and ocean currents, as these factors affect the power required to propel a ship.

2. Ships Must Follow Safe and Organized Shipping Routes

Another major reason is maritime traffic management. Busy areas of the ocean often have established traffic separation schemes and other routing systems.

These systems organize vessels into specific traffic lanes and help reduce the risk of collisions.

According to the IMO, ships’ routing systems are designed to improve navigation safety in areas with heavy traffic, restricted sea room, obstacles, limited depths, or unfavorable weather conditions.

3. Canals Can Change the Entire Shape of a Voyage

Canals can dramatically shorten maritime journeys, but ships cannot always use them. The Suez Canal and Panama Canal are two important examples.

The Suez Canal provides a direct connection between the Mediterranean and the Red Sea, avoiding the need to sail around Africa. UNCTAD reports that approximately 22% of global seaborne container trade passed through the Suez Canal in 2023.

But when a canal becomes difficult or risky to use, ships may need to take a much longer route.

Suez Canal example

A ship traveling between Asia and Europe could normally pass through the Suez Canal.

If the vessel avoids the canal, it can instead travel around the southern tip of Africa at the Cape of Good Hope. That creates a much longer voyage.

UNCTAD reported that hundreds of container vessels were rerouted away from the Suez Canal during the Red Sea disruptions, resulting in longer distances and transit times.

4. Security Risks Can Force Major Detours

Sometimes the ocean route itself is not the problem. The problem can be security.

Ships may avoid certain areas because of:

• Armed conflict
• Attacks on commercial vessels
• Piracy risks
• Regional instability
• Security warnings

When the risk becomes too high, shipping companies may decide that a longer route is safer. This is one reason the same ship route can look very different from one period to another.

5. Shallow Water Can Prevent Ships From Taking a Direct Route

A large ship needs enough water beneath its hull.

This is especially important for:

• Container ships
• Tankers
• Bulk carriers
• Large passenger ships

A vessel with a deep draft cannot safely travel through every part of the ocean. A direct line might pass through shallow water, reefs, sandbanks, or other hazards.

The vessel therefore needs to follow a deeper and safer route. This is one reason nautical charts are important for maritime navigation.

6. Ships May Avoid Canals Because of Operational Conditions

Canals can save enormous distances, but using them is not always simple.

A vessel may need to consider:

• Canal availability
• Transit restrictions
• Water levels
• Vessel size
• Traffic
• Waiting times
• Scheduling
• Operational costs

For example, UNCTAD has reported that reduced water levels affected traffic on the Panama Canal and caused maritime trade to divert to longer routes.

7. Port Congestion Can Influence Route Decisions

The voyage does not end when a ship reaches the destination port. Ports can become extremely busy.

If many ships are waiting to enter a port, vessels may experience:

• Anchorage delays
• Berthing delays
• Slower turnaround
• Schedule changes
• Changes to arrival timing

A shipping company may adjust its voyage plan based on expected port conditions.

For example, a vessel may adjust its speed to avoid arriving too early and having to wait a long time outside the port. This means that speed and route decisions are connected.

8. Ocean Currents Can Make One Route More Efficient

The shortest route is measured by distance. But shipping companies also care about fuel and time.

Ocean currents can influence how efficiently a ship travels. A route with favorable currents may help the vessel maintain speed with less energy.

Meanwhile, sailing directly against strong currents can increase resistance and fuel consumption.

9. Route Changes Can Reduce Fuel Consumption

A longer route does not automatically mean more efficient sailing.

However, route planning is about finding the best overall voyage rather than simply minimizing distance.

A route planner can consider factors such as:

• Expected weather
• Currents
• Vessel speed
• Navigation restrictions
• Stops
• Canals
• Safety
• Arrival time

The goal can be to balance distance, time, safety, and fuel consumption.

10. Ships May Follow Predefined Shipping Lanes

Large shipping areas are not completely unstructured.

Certain routes have become important because they connect major ports and trade regions.

For example, ships may follow established routes between:

• East Asia and Europe
• Asia and North America
• Europe and North America
• The Mediterranean and other major regions
• Major oil-producing areas and consuming markets

Following established routes can improve predictability and safety.

The IMO states that routing systems can include traffic lanes, separation zones, and other measures designed to organize opposing or converging streams of vessel traffic.