Boat speedometer how does it work

Boat speedometers are not the best instruments when it comes to indicating speeds. If you are purchasing or trying out a boat, don't rely on its speedometer. It is best to bring a handheld GPS that will give you close to accurate speed readings. There are two better ways to measure the speed of the boat. They are:. One of the most accurate devices which can be used to read the speed of the boat is a GPS or global positioning system. GPS is regarded to give better reading compared to the speedometer and Pitot tube arrangement.

GPS can be bought and fixed on your boat. You can also purchase a small, handheld GPS which you can use it anywhere. Downloading GPS apps on your smartphone can be a good alternative as well. However, it is best to get a mounted GPS hardware that you can permanently fit on your boat. GPS makes use of your satellite data to measure speeds. The speed is measured by determining the distance between the positions of your boat relative to the earth's surface.

The data that picked up from the satellites allows a GPS to calculate its location on the Earth. Some GPS units are even more accurate as it determines the distance between itself and various cell towers.

Another mechanism that can be used is called an impeller. This is a small propeller that projects from the hull all the way to the bottom of the boat. The working of the impeller is simple.

As the boat moves through the water, it causes the impeller to rotate. The movement of the impeller produces an electric impulse directly proportional to the revolutions of the impeller.

This is then converted into speed and distance. An issue with the impeller is that it can be damaged by any debris on the water since it is projected far below the boat. One of the most frustrating events is when you are cruising on your boat and the speedometer starts to malfunction or stop working altogether. The problem is much more common than you think. It is possible that the speedometer needs to be checked by technicians, but most of the time, the fix is actually quite simple. If the issue is not looked after immediately, you might face bigger trouble later on.

The first thing to do is to find the cause of the issue. Inspect the boat speedometer to find any signs of damage. As you have seen, manual speedometers are not very accurate. Just like your car GPS, these speedometers rely on satellite monitoring. As you move on the water, a satellite tracks your progress from space. That means not only is your position accurately tracked, your speed is tracked as well.

This kind of speedometer is in no way affected by any kind of current. An electromagnetic sensor is sometimes called an electromagnetic log or an EM log.

The sensors are definitely more advanced than manual sensors. They measure speed when a conductor passes through an electromagnetic field. In this case, the conductor is the water that your boat is on. The sensor generates an electromagnetic field. The conductor passing through the field creates voltage which can be measured.

That measurement gives you a speed reading as the voltage will increase along with the speed of the boat. Certain water conditions can affect the reading. That means it may not be as accurate as GPS speedometers. Another popular type of boat speedometer is the electric paddle wheel speed sensor. This kind works by measuring the force of passing water that turns a paddle wheel. The problem with a paddle wheel speed sensor is it is vulnerable to outside elements.

Weeds or debris can clog it and alter the reading or stop it from working completely. When working properly however a paddle wheel speed sensor gives accurate speed readings. There are a number of boating apps you can download on your tablet or phone.

Many of these offer exceptional navigation tools. Related article: Where should a boat compass be mounted. My top pick is this Eling GPS speedometer with curved glass display and red backlight. I like that it has a very quick start-up time of around 3 seconds.

If you prefer a digital dial rather than the traditional style, this universal speedometer is a good choice. It is IP67 rated and has a range of 7 backlight colors to choose between. It will fit in an 85mm hole and comes with the GPS antenna which can be mounted on the top of the dash.

If your boat is already kitted out for a pitometer, then I recommend the Eclipse kit from Sierra International. The kit also comes with the pitot and hose included so you only need to purchase one product.

Properly installing a speedometer on your boat is critical to ensuring that it is accurate and effective over time. When it comes to installing a speedometer, you have two options: do it yourself, or pay a professional.

In fact, depending on the kind of speedometer, the process can actually be quite simple. Check Pricing on Amazon. To get started, I recommend getting this SeaChoice Pitot Speedometer Kit which comes with everything you need to install a pitot on the outer surface of your boat. The kit includes a flexible pitot that can pivot, a black plastic vent, black plastic tube holders, self-tapping screws, and 20 feet of PVC tubing.

Whether you've recently purchased a boat or are thinking of changing its speedo, it's important to know how each option works.

Manual speedometers are a popular option for boat owners because they display how fast you're moving on the water. The pressure gauge will typically be on your dashboard and appear similar to the one in your vehicle, however, a manural speedo uses a pitot tube to estimate your boat's speed.

A pitot tube speedometer, work with pitot tubes that are connected to the dashboard through the underside of the boat through a cable and stick out into the water.

This long, triangular plastic tool travels along the surface of the lake, ocean or river you're boating on and water enters the attached tube which is also connected to the speed gauge. As water fills the tube the air inside it becomes pressurised by the force of the water, explained Best Boat. The change in pressure gives you an estimate of the speed of the boat. This means as you speed up more pressure will occur and the gauge will show a faster speed, and As you speewhile reduced pressure means you're slowing down.

Remember that a water pressure based speedo with tell you speed over water and depending on which way the current is running this will either add on or subtract a bit of the reading. Manual systems are a great way to estimate your speed on the water, if you're upgrading your system, consider opting for a full range of console dials that include a voltage and fuel gauge.