How Fast Is 30 Knots? (Find out now)

Fact Checked By James A Rockey | Post Updated On: November 26, 2022
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30 knots are equal to 34.5234 miles per hour on land. A knot is a speed unit comparable to a single nautical mile in an hour. 1 knot is equivalent to 1.1507794 mph. in average speed for different boats, 30 knots is fast enough to give the thrill since most cruise ships cruise at an average speed of 23 knots.

Key Takeaways

  • One knot is equivalent to 1.15 miles per hour or 1.852 km/h
  • The cruising speed for most ships is around twenty-seven to twenty-eight knots
  • Speed in knots is equal to one nautical mile and the nautical mile is essential in allowing the earth’s curvature in one way or another
  • HSC Francisco is the fastest ship in the world as it can hit up to 58.1 knots, equivalent to 66.86 mph

Comparison of speed in Knots vs. Mph vs. km/h

Comparison of speed in Knots

The table below shows the conversion of knots to mph and km/h. these conversions will help you compare the speed at sea to that of a vehicle and make it more relatable. We convert by multiplying the knots by the conversion factors to arrive at these figures. One knot is equivalent to 1.15 miles per hour or 1.852 km/h.

Knots Mph Km/hr 
3 knots 3.45 mph5.56 kph
4 knots 4.60 mph7.41 kph
5 knots5.75 mph9.26 kph
6 knots 6.90 mph 11.11 kph 
30 knots 34.6 mph55.56 kph
35 knots40.3 mph64.82 kph

How fast is 21 knots on a ship?

If a ship is being sailed at 21 knots, this is comparable to 24 miles per hour, a fair speed for a boat to sail. The cruising speed for most ships is around twenty-seven to twenty-eight knots. However, with up to thirty knots, you will experience the thrill of speed on the water.

Why do boats have knots?

Why do boats have knots

Navigation requires a calculating speed format that is common to all and can easily be understood. With Knots, this is made easier as it is known that speed in knots is equal to one nautical mile. With the earth being somewhat circular, which is an assumption by navigators, the nautical mile is essential in allowing the earth’s curvature in one way or another. Therefore, the average distance traveled even in a minute is easily calculated.

What’ kts’ stand for in speed?

Abbreviations are used primarily to save time and easier understanding and prevent grammar mistakes. The acronym kts can also indicate a knot. It is ‘kt’ when singular and ‘kts’ when plural.

How did sailors measure knots?

The term knots are dated to have been discovered in the 17th century. It was used by sailors even long ago when they were navigating. They used a device called a Common Log. This device was just a simple rope with knots at regular intervals. The rope was then attached to a wood piece shaped like a pie slice. The description may not draw a picture, but this device was one of the most significant discoveries in sailing and navigation.

The fastest ship in the world

The fastest ship in the world

Just as there are fast cars and airplanes on land, there is also the fastest ship globally. This is the Francisco. This ship was made in Australia by a shipyard named Incat. It is the world’s fastest ship as it can hit up to 58.1 knots, equivalent to 66.86 mph. Fast, right? It also carries many passengers, which is up to one thousand passengers. It primarily sails from Australia to Buenos Aires, Argentina, and Uruguay.

What name is given to the nautical mile?

A nautical mile is a unit of length used in three different navigations: air, water, and space navigations. The international nautical mile is around one thousand eight hundred and fifty-two meters. It is also essential to know that the knot is a derived unit of speed and is also equal to one nautical mile per hour.

How deep is a Fathom?

A fathom is six feet deep. It is an old English term related to measuring the length and is equal to 1.83 meters and has been used as nautical unit depth for a long time due to its accuracy. 

How fast are cruise ships?

The average speed of any cruise ship is around twenty knots. The maximum speed is 34.5 miles per hour, approximately thirty knots.

Why do we use knots instead of mph?

Knots are so much easier to navigate. A knot is a speed unit directly tied to the global unit latitude and longitude and coordinating systems. In the nautical and aviation worlds, the preference to use knots is more than the one to use mph and kph.

How is the depth of an ocean measured?

The fastest way is by using sounds. A device known as a Multibeam Echosounder( MBEs), a sonar type that can send rapid sound waves in a fanlike manner to scan the sea’s ocean floor and bottom, is used to examine the sea’s ocean floor and bottom to measure a sea’s depth.

Essential knots for sailors

As earlier discussed, the actual knots are essential and play a massive role in sailing and navigating for sailors.

There are three general knot types; 

  1. Those tied at the end of the line are mostly called knots. Examples of this type are the bowline knot and the stopper knot.
  2. The ones that join two lines together. They mostly have the term bend in their names. The bend in sailor’s language means to join. An example is the sheet bend.
  3. The last category is known as the hitches. Their primary function is to secure a line to cheat, a piling, or a stanchion.

To understand the knots, it is essential first to master what a knot looks like on its completion, then practice how to make it, and this way, it will be very hard for one to forget how it looks.

When it comes to knots, mastering the key terms is also essential. The ends of lines are categorized as either working or standing. The working end is the free end, which is not attached. The standing end is attached to something. If any loop is formed in a line, it is called a bight.

The bowline

It is the most useful knot on any sailboat. It forms a fixed noose at any end of a line. The noose can neither run nor slip and is used in securing sheets to the clew of a headsail. When two bowlines are used, they can connect two lines. A bowline’s advantage is that it can still be untied later on no matter how tight it is earlier fixed to help with issues attaching items.

How to untie the bowline

To untie a bowline, first, turn the knot over and then break it backward by having to bend it downwards.

The stopper knot

A stopper knot is tied to ensure that a line is prevented from pulling through a block or a rope clutch. It stops pulling the rope or the clutch just as its name states. It does not come loose quickly as a simple overhand knot or the figure-eight knot.

The easiest way to tie it is by using your hand to be the form. You then loop the line’s end twice around your palm while tucking in the working end under the two loops. You can then pull the loops away or off your hand.

The clove hitch

It is convenient; hence can be tied within a matter of seconds. It is used in sailboats for securing the fender whips for a very long time. It can also be used to make the toe rail and stanchion base stay for a longer time. It can also temporarily secure the dock line towards a piling; this is another of its many functions. However, it can accidentally work free when the vessel sails around a dock, which can be accidental.

The sheet band

Initially, or in case of a hurry, the sailors use a square knot when tying two lines together. However, because this is a shortcut, it mostly gets loose. However, the sheet band is more secure than the square knot. It is also easy to untie in cases where the lines are of unequal diameter.

The Two-Half Hitches

The name already is explanatory. This is just one-half hitch with another. It is straightforward when it comes to tying it, and it usually forms a running noose that can be adjusted to become larger or smaller depending on how it is used. It comes in handy when one is interested in tying an object tightly.

When combined with a round turn, it works excellently in securing a dock line to a piling. When you tie two half hitches on top of a clove, no cases of the fender whip slipping will be reported as it tightly holds it as you sail.

Apart from the knot as mentioned above and tying design, others include;

  • The Rolling hitch
  • The cleat hitch

Final word

The use of knots is essential when determining the speed of vessels, either when they are navigating or sailing. It can determine whether the speed is too high and therefore reduced, or when the speed I just good with the sailing. We hope you now understand how essential the knots are in navigating, and you can estimate the speed of a water vessel.



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