Bigger is not always better, right? Well, when it comes to sailboats, that is not always the case. Bigger sailboats are, in fact, faster. However, the reason behind that is more complicated than it seems. It is not simply a matter of size but the physical forces at play.
The size of the main body of the sailboat, the hull, is the driving force of the vessel’s speed. In theory, a sailboat’s hull speed is the maximum speed it can attain without surfing. As a result, a boat with a longer hull will have more waterline length — which directly impacts the speed.
Although waterline length and the hull are the primary factors that determine boat speed, they are not the only ones to consider. Other components, such as material, sails, and even weight onboard, can alter your boat’s speed. Having rudimentary knowledge about how speed is affected by each of these items can help you chose the perfect boat and ensure it reaches its maximum potential.
How Size Affects a Sailboat’s Maximum Speed
The mechanics and physics behind sailing are an intricate and interesting concept but can be somewhat difficult to understand. However, the basics are all a good sailor need to understand to be able to successfully navigate the sea.
As mentioned above, the size of the boat, specifically the hull, determines the speed of the boat. Now
we can dive into the science behind it.
Length at Waterline (LWL) and Length Overall (LOA)
You’ll need a few measurements to calculate how fast your sailboat can go.
- The LOA is the length of the ship, measured in a straight line from the tip of the bow to the stern.
- The LWL is the length at waterline. It is the length of the hull that is submerged in water. This is the measurement you will use to determine maximum speed.
To put it simply, LWL is the LOA without any spars that protrude from the hull or the platforms from the stern. (This article has an image that may help you visualize.) Once you have calculated the LWL, you can then determine the maximum speed of your sailboat.
The calculation is: Hull Speed (in knots) = The square root of your LWL x 1.34
For instance, if your LWL is 100 feet, you will get a maximum speed of 13.4 knots.
How Wavelength Figures Into Sailboat Speed
Wavelength is the distance between two successive wave crests, like so. Wavelength impacts the sailboat’s maximum speed. This is where physics takes over.
Here’s how an engineer at MIT put it: “The longer the boat, the longer the wave it generates at higher speeds, and longer waves move faster than shorter waves,” he says. “It’s very difficult for a boat to move faster than the speed of a wave that is as long as a boat.”
For our purposes here, we’ll just say this:
Wavelength is a determining factor of boat speed, the longer the wave, the faster the boat will go.
How to Make a Sailboat Go Faster
But is the speed of a boat all about size alone? Not exactly. There are several other factors that fit into how quickly a sailboat can move along the water. If you want to maximize the speed of your sailboat, here are the things you must keep in mind:
Lose the Weight
Yes, the weight on board alters the speed. Just as everything in life, the more weight its caries, the harder it is for it to move. Boats are designed for a specific payload (cargo), if the cargo is heavier than what it was designed to carry, the ship will be weighed down, have a lower speed and even sink.
For a faster boat, consider removing all cumbersome or unnecessary items. Now that all the deadweight has been removed, your boat will be coasting over the waves.
Consider your Sails
The sails on the boat are there for a reason; they harness the wind and help increase the boat’s momentum. If properly positioned and controlled, the sails allow a boat to reach the speed of the wind.
Although it seems like a simple concept, there is a lot of technique and physics behind this mundane looking task. The sails of a sailboat are remarkably like the wings of an airplane; they have the same function; however, one has mobility while the other does not. Although the two are made of different materials and differ in structure and rigidity, they both provide what is known as “lift.”
Let’s talk about Lift
Lift, more commonly known as a side force, is a force that is exerted onto an object because of the fluid flowing around it. I know what you must be thinking, wind is not a fluid. According to fluid dynamics, any substance that flows is considered a fluid.
Since air flows, it is known as a fluid in the world of engineering and physics. Lift is a component of the force a fluid exerts on a surface as it flows around it. This component is perpendicular to the oncoming flow, which is wind in the case of a sailboat. This wind, blowing against the sail from the side, creates a force to the side and forward. Once a sailor understands this concept, they will be able to travel at the same speed as the wind.
Does a Sailboat’s Construction Affect Its Speed?
Considering that each component of the sailboat affects its weight, construction is definitely a crucial part of increasing a boat’s momentum. If a lighter material is used to construct the hull, the boat will be lighter and have better momentum. A smoother material will also help increase the speed by reducing the friction. For more information on how construction can affect the speed of a boat, check out this
Which Sailboats Are the Fastest?
The world of sailing is a dynamic one, and faster boats are always being built. However, the ranking for fastest boats as of right now is as follows.
- Vestas Sailrocket 2 is the fastest sailboat, with an astonishing speed of 65.45 knots (75.2 mph).
- Hydroptère is the runner-up, had previously broken the speed record in 2009.
- Spindrift 2 is the largest racing sailboat in the world but can still reach high speeds.
- IDEC 3 was the transatlantic speed record holder between 2007-2009.
- GC32 Version 2 is the fastest catamaran (boat with twin hulls) on water.
To check out more boats that rank for speed, check out this website.
Can a Sailboat Go Too Fast?
Sailboats have evolved over the years and are able to move at almost three times the speed of the early sailboats. As new discoveries are made, and new materials are used, boats have become more efficient and dynamic than they used to be a few decades ago. Although the speed has gone through significant increases over the years, it still has not been able to surpass the speed of the wind.
Nevertheless, some people have had experiences where their boat was going too fast and resulted in an unpleasant experience. However, that is entirely subjective. The “too fast” range for a boat will differ from person to person. Safety is your guide in this regard.
Even though there isn’t a predetermined speed limit that is considered to be too fast, lack of attention at certain speeds can lead to fatalities. It is advisable to be considerate and cautious when reaching a certain speed because it can have irreparable repercussions. And, of course, depending on the body of water you are on, there are bound to be no-wake zones to pay attention to.