The Importance of Using a Wind Generator on a Sailboat
Even though wind generators may not be of much help off the wind, they are increasingly becoming more appealing to sailors looking for an alternative source or extra power for their sailboats. The fact that they rely on the same wind that you use to move from one point to the other makes them quite a hit. Additionally, today's marine wind generators have undergone continuous improvement over the last few decades and are now well proven and quite reliable. This is exactly why wind generators are still common in sailing despite the advent of solar panels and hydro generators.
A wind generator will keep your boat's batteries charged at all times as long as there's wind. It doesn't matter whether you're at the port or out on the water, the wind generator will continuously pump out power even on cloudy days. That's not all; wind generators are cost-effective since they're maintenance-free and do not need any launch or recovery. More importantly, there are very powerful wind generator units that can produce more than 400 units of power, which is just enough to keep a fairly medium sailboat running and operating for 24 hours.
But just like with anything that has advantages, there must be some disadvantages. One of the most noticeable downsides of relying on a wind generator is that the power produced by the generator can significantly reduce if there's no wind. Most wind generators can manage to produce about 200 watts of power in wind speeds of 20 knots but things can even become worse when you're anchored at the port since winds are generally very low at the ports. As such, you may need an additional source of power such as solar panels, especially if your sailboat has heavy power requirements.
Installing a Wind Generator on a Sailboat
Installing a wind generator on your boat's charge system is a serious process that requires careful planning and attention. As we noted earlier, this process should start by first assessing your boat's power needs. You should be able to determine the amount of power that your boat and its appliances need to consume in at least 24 hours. This will certainly give you a clue of what you require.
The general idea is to ensure that you don't have to keep your boat's engine running so as to keep your batteries charged because this might not be enough in running your boat's appliances. In most cases, a boat's power needs are modest. Well, the boat generally needs power for lighting, running the navigation and safety equipment, refrigeration, and powering a stereo, if any.
The Equipment Required
One of the most important pieces of equipment required when installing a wind generator on your sailboat is the turbine. Generally speaking, the turbine should be functional at both medium and high wind speeds. You have to, however, keep in mind that even the biggest wind generator won't produce much power if the wind speed is below 8 knots. The turbine should be tough, reliable, and quiet. You certainly do not want a turbine that sounds like an approaching helicopter as this can be so annoying.
Given that early models are very noisy, three-bladed rotors are becoming more and more popular. They are smartly designed with CAD blades that significantly reduce the whistling and thrumming sounds that occur at the tips of the blades. These modern rotors are also designed to be more efficient and reduce friction through the use of permanent magnet alternators that allow speeds of the blades to be reduced, thereby reducing the noise levels considerably.
With that in mind, some of the best wind generators to go for include Air breeze, Eclectic Energy, Leading Edge, Rutland, Silentwind, and Superwind.
The Aerodynamics of Turbine Blades
Ensuring that power moves from the turbine's alternator and safely into your batteries may seem like a simple process. There are, however, aerodynamics involved and it only makes sense if you understand how they work.
In terms of the blades, they operate based on a similar principle or a plane's wing. There may be some differences but they are generally designed to produce optimum output. This means that the turbine blades should not go too fast as it can mitigate the wind generator's efficiency. The same applies if it is too slow. In essence, it works like a car gear so having very high or low gear can be inefficient. The idea here is that the airflow will become unstable if the blades are at very high speeds.
The best way to solve this problem is to rely on the "tip speed ratio". This technically describes whether or not the blade tips are moving faster than the actual wind speed. As such, the blade tips should be moving at 320 knots on 20-knot wind speed but there should also be the survival speed, which is just the right wind speed that is needed to produce the right amount of power to sustain your sailing needs.
The Amount of Power that Your Boat Needs
It's of great importance to budget for the amount of power to ensure that every facet of your sailboat is functioning properly. Of course, there are obvious appliances such as plotters, interior lights, and fridges. There are also navigation lights, engine monitors, entertainment systems, pumps, watermakers, gas alarms, electric winches, hydraulics, and many other things. You should also make a good margin that will have you covered if there's an emergency.
You should also consider other things such as air conditioning (though this may need fuel) as well as the type of sailing you're planning to do. Will you be sailing upwind or downwind? Well, such minute factors can significantly affect the amount of power that your boat needs. It is, therefore, crucial to determine a clear and accurate idea of how much power you need to generate to perfectly operate every part of your boat.
Mounting the Wind Generator
One of the most challenging things that revolve around how to install a wind generator on a sailboat is where to mount it. Location is very fundamental and can either positively or negatively affect how your wind generator operates.
The golden rule that governs the position of the wind generator is quite straightforward. It should be mounted in an area of the vessel where there will be no interruption of the flow of air or wind to the turbine from all directions. Generally, the wind generator is mounted on the boat's mast with two stays. You can easily raise or lower the wind generator if it is installed with a pivoting base. But if it is installed on a fixed mast, it can cause difficulty if you want to secure the wind generator when there's an impending storm.
And because the main aim is to optimize the output from a wind generator, there are a few important things to do. The most important thing is to ensure that it is very stable. This is because even a slight rolling or pitching might just be enough to rotate it away from the wind. The wind generator also requires clean air from all directions and as much as possible.
As you can see, these two principles seem to be at loggerheads given that you'll get more wind speed as you go higher but this may affect the stability of the turbines. With this in mind, mounting the wind generator on mizzen masts can be a good option but choosing to mount the turbine just above the cockpit is an even better option. The idea here is that it will be a lot easier to manually control the turbine if all other options of braking it doesn't work. Again, installing and maintaining the turbine overhead the cockpit is a lot easier than when it is mounted on the mizzen masts.
That's not all; mounting the turbine over the cockpit also means that the cables need to transport power from the turbine to the alternator are much shorter. This means that the wire diameter will be a lot smaller without necessarily affecting the voltage. The fact that the voltage can drop if the wind generator is mounted up higher on the masts should be particularly important.
This is because it can affect the overall performance of the wind generator and the power it produces and this means that the power supplied to your sailboat might just fall short. Again, a considerable amount of weight can be reduced if the turbine is mounted just over the cockpit. The cables will be reduced and the overall stability of the wind generator will be increased if it is installed overhead the cockpit.
Of course, you'll also have to install the electrics that come with the wind generator unit. For example, there's the controller that is used in regulating the power supply from the turbine, as well as the dump load resistor that is essential in absorbing any excessive current that may be produced when the batteries are fully charged. There's also an inline stop switch, which is essential in turning off the unit when it's not in use. Well, most of these installations are straightforward and are generally shown in the unit's installation guide.
Assembling the turbine should also be a walk in the park. Units do come with fasteners and are accompanied by installation instructions that are easy to understand and follow, thereby making the installation and assembling process a breeze.
So if you've decided to install the wind generator overhead the cockpit, which is our best location, you must find a perfectly sized pipe and mount it solidly at any corner of the stern. You have to ensure that you support the pole with at least some diagonal tubes so that it doesn't swivel. And if you are planning for an off voyage escapade, using the hose clamps to secure the main pole might not be the wise thing to do. This is because they'll most likely snap and twist as a result of constant vibration and miles of hard sailing.
Securing Your Boat's Wind Generator
With that in mind, you should also be prudent enough to secure the wind generator if there's a pending storm. As a sailor, you should be prudent, stay alert, and prepared in case there's a storm. The most important thing is to know the dynamic of the wind generator and how to apply electric brakes or even have the turbines lowered when there is a storm.
You can do this if the wind speeds are more than 15mph. This is of great importance in ensuring that the wind generator does not overheat or the blades do not break. You can also choose to remove the wind generator altogether and store it in a safe place.
All in all, the importance of having a wind generator on your sailboat as an alternative energy source can never be downplayed. This is a great source of renewable energy that will have your boat working perfectly well even if you are sailing in some of the remotest corners of the world. Just know how to install the wind generator, have it maintained, and protected when there's a pending storm and you'll be good to go.
Until next time, happy Sailing!