Why Do Boats Use Knots Instead of MPH?

The world of sailing is filled with its own language and terminology, which can be confusing for those who are new to the sport or hobby.

One unit often used in sailing is the knot, which measures speed and distance and is used instead of the more commonly known MPH (miles per hour).

This article will discuss why boats use knots instead of mph, including a brief history, the advantages and disadvantages, different types of knots used on boats, how to measure speed in knots, how to convert mph to knots and vice versa, and finally some sources for further reading.

What is a Knot?

A knot is a unit used for measuring speed and distance specifically in maritime or aviation contexts. It is equal to one nautical mile per hour (1 nm/h), or 1.151 statute miles per hour (mph).

A nautical mile is equal to about 1.852 kilometers (km). The term “knot” comes from early sailors who tied knots in rope as a way to measure speed and distance traveled on their ships over time – they would tie an extra knot into the rope after each nautical mile they traveled before resetting the counter at their starting point when they returned home again!

History of Knots in Sailing

Knots have been used since ancient times as a way to measure speed and distance traveled by ships at sea – it was just easier than trying to keep track with miles or kilometers!

The first recorded use of the knot as a unit was by Dutch mathematician Willebrord Snellius in 1617 when he published his formula for calculating longitude using the Earth’s circumference at different latitudes based on knots measured from an anchor point on land! Since then, knots have become an important part of navigation both on land and at sea!

Advantages of Using Knots

Knots are easier for sailors and pilots alike because they are tied directly into global latitude and longitude coordinate systems – this makes it easier for navigators who need quick calculations or conversions between different units of measure!

Additionally, knots are more accurate than mph or kph because they account for changes in wind direction which can affect speeds over long distances! Lastly, knots make it easier for sailors to compare their speeds against others since they don’t have to convert back and forth between different units – everyone uses knots so there’s no confusion!

Disadvantages Of Using Knots

The biggest disadvantage is that many people are unfamiliar with knots as a unit of measurement – this means that anyone looking up information about sailing will likely get confused if everything is listed in terms of knots instead of mph or kph!

Additionally, using knots can be more complicated when dealing with acceleration or deceleration because it requires more complex calculations that may be difficult for some navigators without specialized training!

Lastly, some navigational equipment may not be calibrated for measuring speeds in knots so that could lead to inaccurate readings if not properly calibrated beforehand!

Different Types of Knots Used on Boats

There are several different types of knots used on boats depending on the type of craft being sailed but some popular ones include: Figure 8 knot which is used as a stopper knot, Bowline which forms a secure loop, Sheet bend which connects two ropes together, Half hitch which secures rope ends, Clove hitch which provides quick release, Round turn & two half hitches which provides extra security, Figure 4 knot which prevents slipping, Reef knot which binds two ends together securely, Timber hitch which grips tightly when pulled, Double Fisherman’s knot which joins two ropes together securely, Anchor Bend also known as fisherman’s knot which creates secure loops around poles/posts/anchors!

How to Measure Speed in Knots

Measuring speed in knots can be done with either specialized instruments such as logbooks or GPS systems or simply by counting how many times your boat passes certain markers over a certain period – this method is especially useful if you need an estimate rather than an exact measurement!

You can also measure speed by timing how long it takes your boat to travel between two points – divide the distance by time taken (in minutes) then multiply that number by 60 (minutes) to get your speed in nautical miles per hour (knots)!

How To Convert MPH To Knots

To convert miles per hour (mph) into nautical miles per hour (knots), simply multiply mph by 0.868976242 – this will give you your speed in knots! For example: If you were sailing at 10 mph then 10 x 0.868976242 = 8.68976242 nautical miles per hour (or 8 knots).

How To Convert Knots To MPH

To convert from nautical miles per hour (knots) into miles per hour (mph), simply divide your speed measurement by 0.868976242 – this will give you your speed in mph! For example: If you were sailing at 10 knots then 10 / 0.868976242 = 11.50779541 mph (or 11 mph).


In conclusion, boats use knots instead of mph because it ties directly into global latitude and longitude coordinate systems making navigation easier for sailors both old and new alike.

Additionally, there are many advantages such as accuracy due to accounting for wind direction changes over long distances while there are some minor disadvantages such as lack familiarity among non-experts but this can easily be overcome with further learning resources available online or through experienced sailing professionals/instructors!

Lastly, there are several different types of knots used depending upon what type craft one sails but all involve tying extra pieces onto existing ropes/lines before counting them off after each nautical mile traveled before resetting at their starting point once back home again!

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