FutureStarr

A Boat Speed Formula

A Boat Speed Formula

Boat Speed Formula

via GIPHY

When we talk about boat speed, we’re referring to how quick the boat can move through the water.

Speed

Hull speed or displacement speed is the speed at which the wavelength of a vessel's bow wave is equal to the waterline length of the vessel. As boat speed increases from rest, the wavelength of the bow wave increases, and usually its crest-to-trough dimension (height) increases as well. When hull speed is exceeded, a vessel in displacement mode will appear to be climbing up the back of its bow wave. From a technical perspective, at hull speed the bow and stern waves interfere constructively, creating relatively large waves, and thus a relatively large value of wave drag. Ship drag for a displacement hull increases smoothly with speed as hull speed is approached and exceeded, often with no noticeable inflection at hull speed.

) because of the rapid increase of resistance from the transverse wave train. When the Froude number grows to ~0.40 (speed/length ratio ~1.35), the wave-making resistance increases further from the divergent wave train. This trend of increase in wave-making resistance continues up to a Froude number of ~0.45 (speed/length ratio ~1.50), and peaks at a Froude number of ~0.50 (speed/length ratio ~1.70). (Source: en.wikipedia.org)

Boat

Hull speed or displacement speed is the speed at which the wavelength of a vessel's bow wave is equal to the waterline length of the vessel. As boat speed increases from rest, the wavelength of the bow wave increases, and usually its crest-to-trough dimension (height) increases as well. When hull speed is exceeded, a vessel in displacement mode will appear to be climbing up the back of its bow wave. Wave-making resistance depends on the proportions and shape of the hull: many modern displacement designs can exceed their hull speed even without planing. These include hulls with very fine ends, long hulls with relatively narrow beam and wave-piercing designs. Such hull forms are commonly used by canoes, competitive rowing boats, catamarans, fast ferries. For example, racing kayaks can exceed hull speed by more than 100% even though they do not plane.

Most of us want to know our boat’s top speed but don’t know how to calculate it. And, just as likely, we don’t think we need to. GPS is a good way to figure out your boat speed with no effort. It does all the work for you with just a glance. But it’s not always going to be available, especially if there’s a service disruption or an issue with your power. Plus, what if you want to know before you get on the water? Fortunately, calculating boat speed doesn’t have to be that hard. Let’s take a look at what you need to know. (Source: www.boatsafe.com)

Water

Boats and streams is one of the most common topics in quantitative section of all the entrance exams such as Bank PO, CAT, XAT, CLAT etc. It’s also included in aptitude section of many job test in companies like TCS, Infosys etc. This a very simple topic and mere require direct application of formulas to solve the question. However, many students find this topic confusing and find face difficulties in solving them. And, the reason for facing such hindrance is the understanding of the language of question. They are just Speed, Distance and Time questions in water rather with a slightly twisted language. In this blog, today I will provide you all the formulas and their application to make understand this concept and application so that the next time you get any question based on this topic in any exam it’s a smooth ride!

Most of us want to know our boat’s top speed but don’t know how to calculate it. And, just as likely, we don’t think we need to. GPS is a good way to figure out your boat speed with no effort. It does all the work for you with just a glance. But it’s not always going to be available, especially if there’s a service disruption or an issue with your power. Plus, what if you want to know before you get on the water? Fortunately, calculating boat speed doesn’t have to be that hard. Let’s take a look at what you need to know. (Source: www.boatsafe.com)

Use

The water that stays till without flowing is called as the still water. The speed of the boat in still water will vary from the stream water. But based on the speed in the stream, the boat speed in still water can be calculated. Here is the speed of boat in still water calculator which provides you the speed in still water and stream rate based on the speed of the boat in upstream and downstream. This tool fetches result based on the commonly used speed in still water formula. The above examples are just few simple and basic application of the methods stated along with them. These formulas can come in handy and can save lot of your time in exam. You can find questions and problems involving simultaneous use of more than one formula at times. But if you know the correct utilization of them you can solve any problem easily. And, this smoothness comes with practice so the more you varied questions you try the more you will learn and become better at solving them. So, keep practicing!

Why does this formula exist and the other formula as well? This calculation is older and not as accurate. For instance, your waterline length can actually change as your speed increases. Thus, the accuracy is very suspect. Plus, when you add power sufficient enough to overcome hull drag, this number no longer applies. That means when you’re using your motor for propulsion, our original equation is far more useful. This one here is really more something you should be aware of. You may find it when you Google boat speeds and wonder why the different formulas exist. Even boat manufacturers ignore this calculation these days. It just doesn’t apply to modern boat making in any reasonable way. (Source: www.boatsafe.com)

 

 

Related Articles