A bridge too close

There is a plan to build a bridge over the river Guadiana, to connect Alcoutim, on the Portuguese side, and Sanlucar de Guadiana on the Spanish side. We wonder if the bridge is a good idea. Because we adore the undisturbed beauty and silence of this place. Will it help these little towns? We are concerned that this bridge will not bring them the desired economic development. Then it would just be a waste of money, spoiling all that makes this place special.

The Spanish Sanlucar de Guadiana seen from Alcoutim…..
and Alcoutim in Portugal seen from San Lucar Guadiana.

The silent call of the Guadiana

A strong flood takes the sailing ship from the mouth of the river Guadiana, under the bridge near the cities Vila Real and Ayamonte, about 15 miles all the way up to Alcoutim and Sanlucar.  

A sailor arrives here when the flood stream starts slowing down to a nice flow. You feel the calm, the peace here. Time to anchor. Easy, because the Guadiana has plenty good anchor grounds. 

The village of Alcoutim has about 1000 inhabitants, Sanlucar about 400. Both places are located ‘at the end of the country’. Or even at the end of Europe. Well, at least it feels that way. Our Portuguese friends all see Alcoutim as the ultimate place of peace and silence in Portugal. They come here, over the little roads, and for them this area is the place to be. The Portuguese and Spanish tourists come to these far ends to enjoy the silence, the handful of friendly restaurants and bars and the idea to retreat in case you need a real still, buzz free holiday at end of the world.

You can kayak, swim, make a small river cruise. If you want to go to the town on other side of the river, you ask the man of the ferry boat to take you there. 

There is also a cable from the one to the other side. Great for hikers. The Portuguese and Spanish walks are fabulous all year round, not in the least because of the undisturbed landscape and silence.

You can walk several beautiful trails here, all equally quiet. Lovely, even when it’s raining.

Our “Ya” is staying here in winter. For decades, there has been a small sailors population of some 50 sailing boats depending on these villages for their services. Each village has a small dockside, which guarantees an international ambience. 

We like our walks here. The area around Alcoutim and Sanlucar is quiet. As long as we’ve been here, the silence is broken only by the occasional motorboat, a single car passing by, roosters crowing, birds singing, a barking dog and people talking. When the sun shines sometimes there’s music from people playing instruments, alone or together. 

A bridge? 

Once every three year there is a bridge during the Festival do Contrabando  (Smuggler’s Festival). Small scale theatres, arts and artisans on both sides and a temporary bridge connecting the villages. This attracts lots of tourists. 

There is a temporary bridge during the Festival of the Smuggler, and that attracts lots of tourists (photo: Nuno Costa, Sul Informacao).

Now, the Portuguese and Spanish local administration have made plans to build a bridge between the villages. This could help connect both sides. With a car it would take 10 minutes from village to village, instead of an hour. But which local would want that? If you would want to just cross the river, you can also go by ferry. This takes 10 minutes if you include the waiting. In general, there seems to be little exchange between the people of the two villages. The only ones crossing the border seem to be the sailors. There is one Spanish commuter regularly going up and down, and there are tourists, mostly hikers, crossing over by the ferry boat. 

The sparsely populated rural areas on both sides would not generate a lot of traffic. There is already a bridge over the Guadiana in the north (near Mertola), and one in the south (near Castro Marim), both about 30 km away. Sanlucar could benefit from the fire brigade and the health services in Alcoutim, if there wouldn’t be institutional and language barriers to be bridged first. 

The sparsely populated area on both sides of the river is connected by bridges. We have indicated them with arrows on the map: they are near Castro Marim in the south and Mertola in the north. Both bridges are located about 30 kilometres from Alcoutim and Sanlucar.

We are asking ourselves: who is really going to benefit from this bridge. Will there be economic development because of the bridge? From what sectors? There’s hiker’s tourism, some small scale agriculture, no mining or other industry. So, tourism might be one of the viable sectors. But then the question is: what do tourists want? We think the tourist who come to this kind of remote area wants good food, nice walks and a pleasant environment. 

The sound of a pleasant environment

A pleasant environment. Now we sailors and hikers get interested. Especially Peter, as an environmental scientist. He did a small ‘sound check on the spot’, as follows. He made a 10 seconds movie on a popular hiking trail. Just a random movie, so under the film you here the silence, with a footstep, some buzzing flies and a bird. This film-and-sound is recorded some 800 meters from where the bridge might be projected. We expect it will be a bridge with two lanes, with cars passing at 80 to 100 km per hour. So, then Peter put the noise of this kind of road under the same film-and-sound. Here under you see and hear the result. 

The first 10 seconds you hear the environment when you hike there.
The next 10 seconds is what you hear with a bridge near Alcoutim and Sanlucar with traffic.

This traffic noise is not loud. It would comply with the regulations about noise pollution, so don’t worry. But you would hear it. And it completely overwhelms the tiny sounds that a hiker, a sailor comes for, what many tourists enjoy. This region is one of the few where silence is not yet broken. Lucebert, a Dutch poet once wrote: Everything of real value is defenceless.  We would say: the sound of nature is at least vulnerable. Maybe we appreciate silence more because we have lived in big cities and we know what it’s like when you’ve lost it.

A revaluation

So, let us reweigh the plan of this bridge against the loss of silence in this environment. 

In the past decades, the roads to Alcoutim and Sanlucar have greatly been improved; they are small but good. You can easily travel to and from the tourist hotspots of Vila Real de Santo Antonio and Ayamonte on the coast. For tourists, there seems to be no particular added value that a bridge for cars might have. Also, the local inhabitants don’t seem to particularly need this infrastructure.

If you would really like to facilitate cars passing, a reaction ferry like here in Westerhuesen might be a better idea. 

Perhaps an elegantly shaped bridge for pedestrians and bikes might be of true added value. Especially if the bridge itself would be worth visiting, like the hanging Geierlay bridge or the Pedro e Inez bridge in Coimbra. They would have to allow for sailing boats passing through, so the bridge should at least be 20 metres high. Other ideas to strengthen the local economy might also be welcome, like cooperation on cultural activities, development of the regional cuisine, crafts but also attracting digital nomads like the island of Madeira is doing now.

A bridge for pedestrians or cyclists could be of added value, like the Geyerlei bridge (sources: justgo and pixeo)

What to do?

Concerned locals have started a website with information and a letter you can sign (in English, French, Portuguese and Spanish).

Everybody who is related to this area (also as a tourist) can leave his or her opinion at the www.salvaguadiana.com


Nortada brings silent wind

The Nortada, the Portuguese Northern Wind, brought us to the Algarve. We have been here for a while now, happy victims of the Guadiana Glue. Since our wind generator broke down, we wanted to select a new one. Which one? In this article we compare the three most used quality wind turbines: Air Breeze, Superwind and SilentWind.

Airbreeze (with SilentWindblades), SilentWind and Superwind

We compare these three wind generators because they are universal. They can handle all batteries, can be combined with solar panels and other generators, and they are available in 12, 24 and 48 Volt. They are often used on yachts and they are all good, high end generators.

We chose for the SilentWind for its light weight, low noise, the power in also the high range, and the low maintenance.

The yield is in the height!

If you really want a wind generator to deliver, then it needs height. Don’t put it on a 3 metre pole on your boat, but put it higher than 5,5 metre, away from wind obstacles. Then it delivers double, because that is where the wind blows.

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This is the Zaan at Zaandam from Claude Monet. The 17th century Holland was packed with windmills, used for all sorts of industry. They determined, when higher than 5,5 meter, the wind became significantly stronger. This rule could very well be sufficient on yachts.

This ‘higher-than-5,5’ metre rule dates from 17th century. They figured this out in the time that building high mills was difficult, while the wind in Holland was crucial for the industry there. In those days, the Zaanstreek was the innovation centre of Holland, the dominant and richest country of the world. It was full of windmills, for sawing wood, grinding grain, and they were pumping the water out of the polders around Amsterdam. They could use every sigh. This ‘higher-than-5,5-metre’ rule nowadays is interesting for us sailors.

The diagram on the left shows the windspeed windward of an urban place. On the right, you see the diagram of the wind speed on the lee side. A windmill must be put much higher than the disturbing buildings to catch good wind. (Source: Fernando,J .(2010). Fluid Dynamics of Urban Atmospheres in Complex Terrain. Annual Review of Fluid Mechanics, Vol 42, s365‐389)

Check the picture above. The wind blows from the left to the right. On the left side you see a diagram of the ‘clean’ wind. The wind is there if not too close to the surface.  The wind blows over the buildings and creates turbulence above it. On the right side you see the influence of these obstacles.  For good wind, you have to be far above that ‘stuff’. This also underlines the +5,5 meter rule from the 17th century, when obstacles in the field were not higher than the cattle and the grain. And this corresponds with our yacht: a hull on the water, with a railing and stuff on deck. So we’d better stick to that +5,5 meter rule.

If ever you want to remember anything about the yield of windmills: the height is essential. A cheap windmill put on 7 meter, gives a a far better yield than a high-end windmill put on 3,5 meter.

From here we go into the nuances and details.

The windmill on the Ya is over 7 metres high. There’s metres free of obstacles, and you need that to get good wind generation

More height – less weight

A sailing yacht should not capsize. The ‘Ya’ is an ocean approved yacht and complies with the highest standard; even with the mast top blown into the waves she still self-righting. So, all high things on board are necessarily light things.

There are two pretty light wind generators. The lightest is the Air Breeze (5.9 kg). SilentWind a bit heavier (6,8 kg). Heaviest is the Superwind (11,5 kg).

The Superwind is too heavy for a yacht like the Ya; we would have to put it two times lower and this is close to nonsense. But it is a good turbine for a bigger yacht.

The power – it is in the range, not at the peak

The peak power number only gives an impression for a first orientation. All three wind generators are in the range of a couple of hundred Watts. Instead of the peak power, you must look at the power curves. Then you understand the power of a windmill and what suits you.

The Air Breeze (red line) may be the smallest in peak power, but this light mill delivers already 75 Watt at 15 knots wind speed, which is of great value in the leisure sailor’s wind. And there is an extra power peak in the 6 and 7 Beaufort (when there is mostly overcast, so no solar power). You always sail in strong winds? Take the Air X Marine (blue line).
The SilentWind continues its increase till 28 knots of wind. This When over 7 Beaufort, it supplies an awful lot of electricity. In this graphics you also see that generating on high voltage is more efficient; the 48 Volt version yields nearly 25% more than the 12 Volt version.
The Superwind is heavier and delivers slightly more from the first cut-in, and from 25 knots of wind (12 m/s) it delivers 350 Watt continuously. The internal regulation dictates that the 12, 24 and 48 Volt versions all deliver the same 350Watts.

Shrieking, madness….and then silence

We are cruisers. We love nature and the silence. We want our wind generator to deliver energy, not the noise.

All three windgenerators have 3 blades. This is a compromise between efficiency and noise. Interested in the technological reasons why? Rosie explains it simple and straight here.

On the Ya we started with the Air Breeze with the standard blades. From the first cut-in, it started making noise. First you like it, because it delivers. But when it really starts delivering and nears the 15 knots of wind, the blades produce a high shrieking sound. The first neighbour started to complain. At 20 knots of wind the neighbours got angry.

Then we discovered the silent blades. Made in Portugal by SilentWind. A high-end product, just as the price of over 300 Euros. But it was worth every penny. Now the same Air Breeze was making a bit of a whistle till 10 knots, a more serious whistle with more speed, and when the wind is somewhere between 15 and 20 knots, the wind generator’s noise drowns into the ambient noise of the wind blowing through the rigging of the boat.

The Air Breeze with the original blades. When equipped with the blue low noise SilentWind blades, you maintain a good relationship with your neighbours.

Now we have the SilentWind. When the rotation is slow and you listen well, you can hear the sound created by the magnets or the new bearings. At 8-12 knots you hear a light low whistle and when faster it becomes a friendly lower tone with more volume. When over 15 knots, the noise drowns into ambient wind noises.

The Superwind you will not hear from 20 knots of wind. I listened many times to this mill in several situations in light winds, and it is really low noise. But nothing beats the SilentWind.

Brakes and no brakes

All three can be switched off manually, for example when there is not enough wind. The switch simply makes a short circuit. The Air Breeze and SilentWind also use this short circuit brake to prevent too much speed, which is near hurricane.  Before the blade tips would reach bullet speeds, spin out of control and could be ripped from the turbine, the electronics create a short circuit and the blades will slow down to a near stop.

The SuperWind solves this differently, with smart blades. From 25 knots the blades automatically start to adjust their pitch and the rotation speed will not increase. So, in a severe storm, when there is not much sun for your solar panels, the Superwind keeps on generating energy for you.

One could say that the extra moving parts of the Superwind blades have more chance to fail than the simple fixed set of blades of SilentWind and Air Breeze. But this elegant mechanical solution is perhaps safer than the electronic shut off, because also electronics can fail.

Every windmill can be pre-set to stop generating electricity when a certain voltage is reached. Air Breeze and SilentWind simply use the same short circuit brake to prevent overcharging. Since Superwind does not have this brake, all the excess electricity is regulated to go into big capacitators that will get warm, or even hot, and will be cooled by the air around it in your engine room. I don’t like that for leisure sailors. In wintertime the consumption is low and the battery full, while the winds are strong. Then, when nobody is on board, the capacitators in the engine room or cabin cupboard get very hot. It doesn’t give me a safe feeling.

The Superwind

Keep your maintenance low

Superwind designed the mill to keep the maintenance low. The blade pitch against too much RPMs and the double bearings are two examples. Great, but all together it became too heavy for us.

Our Air Breeze broke down. It did not work properly in the medium wind range. Was it the circuit board? We lowered the mast, unmounted the shaft, et cetera and took the circuit board out. We sent it to the service. It was renewed. We remounted everything, put the mast up again, and it ran well. One week later, the same problem. We lowered the mast… to cut a long story short, we lowered and raised the mizzen mast six times (Thanks to Piet, Tulga, IJsbrand, Henk, Jaap, Mick, Inez and others). We also renewed a chip up there, and other things.

The electronics of the Air Breeze are extremely simple. Great, I love KISS. But they are in the housing of the turbine. Too high to keep an eye on it or maintain it.

Then one morning, we were on the river Guadiana and I saw a strong breeze running over the water towards us. I looked up the mizzen, and saw the Air Breeze hardly responding. I knew, this was its last breeze. Our Air Breeze was no more. We declared it our late Air Breeze.

After these ups and downs, I learned what had to be down. That’s chips, diodes and circuit boards. They don’t belong in the top of your mast, where the rain and moist and salt from the sea reign and you can’t look after it. If you want to keep your maintenance low, then keep it low. Superwind and SilentWind put the electronics in a box (converter or MPPT) and you mount that box in your engine room or cabin or any other dry place. Ofcourse it can break down, but in that environment the chance is smaller and the (preventive) maintenance is easy there.

Why the SilentWind is Ya’s pick

Weight=height. On the Ya the windmill can be put on 7 meters high, on the mizzen mast. If…. the generator doesn’t weigh too much. The 6 kilograms of the Air Breeze and the Silentwind don’t influence the stability of Ya. The Superwind with its 11,5 kilograms should be mounted half way. But on 3-4 meters height there is simply not enough wind to justify such a high-quality piece of equipment.  

Silence. All three are reasonably silent. (if the Air Breeze has the low noise blades). On the other hand, if you are on anchor somewhere in the middle of a creek enjoying the singing of the godwit, bluefinch and specked spoonbill, and then a light breeze picks up, you will enjoy the off-switch of your wind generator.

Which is the best on low noise? My private opinion is that the SilentWind -what’s in a name- beats the Superwind.

Power range. All three deliver well in the critical wind range we like to sail in, or when we anchor in a more open bay. The Air Breeze is best in ‘our’ leisure sailors wind range and falls back in the higher regions. The Superwind is doing about the same, but is cut on 350Watts from 25 knots. The SilientWind continues in the high range. We are also interested in the production in stronger winds, when the weather is bad and our solar panels don’t deliver. Then the 12 Volt delivers continually 420 Watts. The 48 Volt version -which is of our interest- delivers even 520 Watt, so much better than Superwind (350 Watt) and the Air Breeze (200 Watts). Our battery capacity is big enough, it is seldom full, so let it all come in, SilentWind!

Regulation You can look deep into the regulation. We love KISS, and then the Air Breeze comes close with a simple circuit board built in the mill. SilentWind’s regulation is based on the core business of the wind generator: to take all energy it can get from that wind, from the cut-in speed to the safety limit at gale wind. The only disadvantage is that you have a big MPPT in your engine room.
I do like the blade pitch solution of the Superwind to keep on running smooth in even a hurricane. But I don’t like that the mill keeps running when the battery is full and the capacitators can get hot. Batteries are full when there is no consumption, so mostly when nobody is there. Then we don’t want critical hot things on board.

Low maintenance. A special word to Superwind. They have put a lot of attention to durability and low maintenance. Unfortunately, this is also the reason that it became too heavy to be effective on the Ya.

I see maintenance, preventive or repairs, as a daily custom for the sailor. But our Air Breeze signed its death warrant when it had to be lowered from the mizzen for the 8th time to check the circuitboard. The SilentWind (and also Superwind) keeps this delicate stuff in the converter or MPPT, to be mounted low, e.g. in your engine room.

Conclusion: We chose SilentWind. Please mail info@fossilfreearoundtheworld.org if you have any comment. We’re curious what you choose and why!