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Panel mounted with bungee cords on sailboat boom for use while at anchor, buoy or dock with no shore power

Solar electric power for boats
Interactive guide to help you find the optimal solar solution
for your boat and needs!

(click on one)
What size of installation do I need?
Where should I install the panels?
What type of panel should I choose?

This interactive guide is protected under U.S., EU and other international copyright laws and may not be reproduced or used outside our web site without the explicit permission of Aurinco. The answers provided are only for guidance, we cannot guarantee the performance of an individual installation.

Where should I install the panels ?

Solar panels produce most energy if they are mounted directly facing the sun. But that is difficult to achieve on a boat given that both the sun and the boat will move. We have seen descriptions of devices that will rotate the panel so that it will follow the sun, but whether there is enough gain to compensate for practical and reliability issues on a boat at high sea remains to be seen. There is also the question of shading, especially on sailboats. So in most cases it will be necessary to make a compromise. Let's look at some scenarios, bearing in mind that our suggestions are for summertime at higher latitudes when the sun is high and stays up long, or for all year in the tropics. If you need to squeeze out some solar power during winter months, panel direction is much more critical.

The panel is used to keep batteries topped off while I'm away
My boat is moored to a dock

In this case it makes sense to mount the panel at an angle so that it is directed towards the sun during peak midday hours. The boat is presumably always tied up in the same direction. However, avoid placing the panel in a spot where it can catch shadow from surrounding boats or structures. It is better to choose a position that may be not be optimal for midday sun but is free from shadow. You may want to mount the panel so it can be removed or mounted in another place while underway.

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My boat is at sway from a buoy or anchor

Mount the panel horisontally in a place which has no permanent shadow. The panel may not be optimally inclined against the sun but it will catch an amount of sunshine regardless of the the direction of the boat or the position of the sun.

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The installation should be optimized for "gunkholing"
i.e. while at anchor or tied down in a quiet bay or natural harbor
I have a powerboat

Best place for the panels is to mount them flat on the cabin roof, on an arch or on top of the bimini. There they will catch sun all day. They may not have the optimal inclination but what counts is the total power produced during a long summer day, not the peak output during a few noontime hours. Come on, you don't want to run around adjusting panels while you take a siesta or enjoy your favorite brew!

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I have a sailboat

Here there are several options but a key point is to avoid shadow from the mast, boom or a furled sail (the thin shadow from a stay is usually not a problem). One solution is to use a lightweight panel which can be placed whereever there is sun, moved around as required and stowed away when not needed or conditions are rough. An example of such a lightweight panel is the long and thin Aurinco Bluewater which can be temporarily secured on the top of the boom with a pair of bungee cords.
For permanent mounting, try to find an area on the deck or cabin with a minimum of both shadow and foot traffic. You can step on all of the Aurinco panels but you will want to avoid dulling of the surface and burning your bare feet (the panels get quite hot in the sun).
You can also mount the panels permanently at the stern, on a pole or suspended between backstays. There it is free from shadow most of the time when the sails are down. Sometimes the panel is mounted horisontally requiring no interaction, sometimes at an angle which will have to be adjusted frequently according to the position of the boat and the sun. The latter is more of a hassle but you may be able to squeeze out a few extra watts. As a sailboater you are used to constantly adjusting sails and trims! But there are drawbacks with an elevated stern installation. One is that it can act as a sail while underway, another is that many people find it ugly, a third one is that a pole mounted panel can interfere with putting out lines or other operations from the stern.

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Portable 80W installation

Fixed 40W installation

The panel should provide power while under sails
My sailing is mostly in-shore, often in narrow waters

Here we would recommend a permanent horisontal mounting. It is too much work to try to turn an inclined panel so that it will face the sun when you are busy sheeting in sails during tacks. You are likely to forget it with the result that the panel will not be exposed as intended.
Try to find an area on the deck or cabin with a minimum of both shadow and foot traffic. You can step on all of the Aurinco panels but you will want to avoid dulling of the surface and burning your bare feet (the panels get quite hot in the sun).
You could also suspend the panel horisontally between backstays or other stays where it does not interfere with the rigging. Or mount it horisontally on a pole at the stern. We have successfully done that on top of a radome, it did not interfere with the radar. Do remember though that a larger panel in an elevated position can act as a sail and affect the speed and the steering of the boat.
An important consideration is shadow from the sails. It is often better to install two smaller panels on each side of the boat rather than one big panel in the middle, then at least one panel will be exposed on each tack.

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Please feel free to contact us for further advice or explanations.

I'm crossing an ocean or large open stretches of water

In this case you could also consider an inclined mounting for the panel since you will probably have time on your hand to adjust the panel to face the sun during long legs (assuming the sea is not too rough). For other suggestions, look at the column to the left.

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On the way to Africa in a 25ft Jeanneau Sangria with 80W of solar power...

© Aurinco 2009-2011

Last update 23JAN2011

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