Thursday, July 18, 2024
shipping and freight resource services
HomeEducationWhat is the Beaufort Scale and its uses in maritime industry

What is the Beaufort Scale and its uses in maritime industry

  • Terminal operations were impacted due to heavy winds, rain, and high swells – the port closed
  • Ship arrival delayed due to heavy winds
  • CTCT windbound since yesterday 4 am and the rest of the week does not look good. Terminal tried to start up a few times yesterday but could not. (this announcement is current in Cape Town)
  • Terminal expects to lose 3-4 days again this week due to weather but will monitor (this announcement is current in Port Elizabeth)
  • Appointment slots will be suspended due to unexpected winds (this announcement is current in Durban)

Many in the shipping industry have seen/heard and read notices like the above from carriers, ports, and terminals around the world..

Wind, has the ability to affect port and ship operations severely often causing delays, damages to ships, containers falling off at sea, and in some extreme cases fatalities..

So what are the basics around how the ship crew, ports, and others measure something as unpredictable as the wind, and conditions of the ocean surface effectively..

Say hello to the Beaufort Scale..

Maritime navigation has for centuries been dependent on navigational charts and various scales of measurements..

The Beaufort Scale is one such crucial tool in maritime operations developed in the early 19th century (the year 1805) by Sir Francis Beaufort of the British Royal Navy to provide a standardized way to describe wind speed based on observed sea conditions..

The Beaufort scale, officially known as the Beaufort wind force scale, is an empirical measure for describing wind intensity based on observed sea conditions..

The Beaufort Scale is set out as a descriptive table depicting the force of the wind as a series of numbers, ranging from 0 to 12, with each level representing a specific wind speed and corresponding sea state..

The Beaufort Scale remains essential for mariners, ensuring safe and efficient navigation by offering a consistent method for estimating wind power when there are no instruments to assess and measure wind speeds and sea conditions..

The Importance of the Beaufort Scale in Maritime Operations

The Beaufort Scale’s primary importance lies in its ability to enhance maritime safety by providing a clear and universally understood system for describing wind conditions..

It helps mariners make informed decisions about their voyages by assessing wind speeds to prevent accidents, particularly in adverse weather conditions..

For instance, knowing that a force 6 wind indicates a strong breeze with speeds of 22-27 knots and corresponding sea conditions helps in planning routes and adjusting ship operations to avoid danger..

Encountering a force 8 gale might prompt a ship to seek shelter or reduce speed to minimize damage and ensure the safety of the crew..

The scale is also crucial in search and rescue operations as understanding the wind and sea conditions is essential for rescuers to plan their missions effectively and ensure they can locate and assist vessels in distress swiftly..

Meteorologists currently use many modern methods such as anemometers, Doppler radar, and monitoring the deflection of rising weather balloons and radiosondes from their points of release..

The Beaufort scale however is still seen as a useful tool in estimating wind characteristics for measuring and describing the effects of different wind velocities on objects on land or at sea..

How to Read the Beaufort Scale

Reading the Beaufort Scale involves understanding the different force levels and their descriptions.. Each level, from 0 to 12, corresponds to a specific range of wind speeds, measured in knots, and describes the resulting sea state..

Force Speed Description Specifications for use at sea
(mph) (knots) Specifications for use on land
0 0-1 0-1 Calm Sea like a mirror.
Calm; smoke rises vertically.
1 1-3 1-3 Light Air Ripples with the appearance of scales are formed, but without foam crests.
Direction of wind shown by smoke drift, but not by wind vanes.
2 4-7 4-6 Light Breeze Small wavelets, still short, but more pronounced. Crests have a glassy appearance and do not break.
Wind felt on face; leaves rustle; ordinary vanes moved by wind.
3 8-12 7-10 Gentle Breeze Large wavelets. Crests begin to break. Foam of glassy appearance. Perhaps scattered white horses.
Leaves and small twigs in constant motion; wind extends light flag.
4 13-18 11-16 Moderate Breeze Small waves, becoming larger; fairly frequent white horses.
Raises dust and loose paper; small branches are moved.
5 19-24 17-21 Fresh Breeze Moderate waves, taking a more pronounced long form; many white horses are formed.
Small trees in leaf begin to sway; crested wavelets form on inland waters.
6 25-31 22-27 Strong Breeze Large waves begin to form; the white foam crests are more extensive everywhere.
Large branches in motion; whistling heard in telegraph wires; umbrellas used with difficulty.
7 32-38 28-33 Near Gale Sea heaps up and white foam from breaking waves begins to be blown in streaks along the direction of the wind.
Whole trees in motion; inconvenience felt when walking against the wind.
8 39-46 34-40 Gale Moderately high waves of greater length; edges of crests begin to break into spindrift. The foam is blown in well-marked streaks along the direction of the wind.
Breaks twigs off trees; generally impedes progress.
9 47-54 41-47 Severe Gale High waves. Dense streaks of foam along the direction of the wind. Crests of waves begin to topple, tumble and roll over. Spray may affect visibility
Slight structural damage occurs (chimney-pots and slates removed)
10 55-63 48-55 Storm Very high waves with long overhanging crests. The resulting foam, in great patches, is blown in dense white streaks along the direction of the wind. On the whole the surface of the sea takes on a white appearance. The tumbling of the sea becomes heavy and shock-like. Visibility affected.
Seldom experienced inland; trees uprooted; considerable structural damage occurs.
11 64-72 56-63 Violent Storm Exceptionally high waves (small and medium-size ships might be for a time lost to view behind the waves). The sea is completely covered with long white patches of foam lying along the direction of the wind. Everywhere the edges of the wave crests are blown into froth. Visibility affected.
Very rarely experienced; accompanied by wide-spread damage.
12 72-83 64-71 Hurricane The air is filled with foam and spray. Sea completely white with driving spray; visibility very seriously affected.
Beaufort Scale showing wind conditions for both land and sea
AR Brink Associates, Durban

This image from AR Brink Associates shows the impact of the different wind speeds both on land and sea.. Click on the image to view the full size..

Extra Fast Fact (Courtesy: National Geographic)

Hurricane warnings are issued when winds reach 12 on the Beaufort scale. But actual hurricane categories are determined by different factors. A 12 on the Beaufort scale is a Category 1 (lowest level) hurricane, but a 13 on the Beaufort scale is not a Category 2; it’s actually much, much stronger.


The Beaufort Scale serves multiple purposes in maritime operations and where modern wind speed instruments are not available either on land or sea, its most obvious use is in weather reporting and forecasting, allowing the ship to plan safe and efficient voyages..

The Beaufort Scale is also used in Aviation.. As per the US DOT’s Air Traffic Organization Policy, the Beaufort Scale is the standard to be followed in the absence of or malfunctioning of approved wind measuring equipment..

Liked the content..??

Sign up below to receive the best and most reliable industry content for free from THE Definitive Online Resource for Shipping and Freight..




Hariesh Manaadiar
Hariesh Manaadiar
I am Hariesh Manaadiar, the Founder of Shipping and Freight Resource.. I have been in the dynamic shipping and freight industry for over three decades and have worked in several sectors.. I share my experiences and knowledge of the industry through this blog for those looking for help in the industry.. Stay subscribed for more free useful content about shipping, freight, maritime, logistics, supply chain and trade..



Please enter your comment!
Please enter your name here

This site uses Akismet to reduce spam. Learn how your comment data is processed.



Sign up below to receive the best and most reliable industry content for free from THE Definitive Online Resource for Shipping and Freight..

FBX - Freight Indices