Blog listing

How to calculate power consumption on a sail-boat

Before deciding about your prefered way of storing electricity on board, a few things need to be considered: you have to estimate your power consumption and therefore know the necessary storage capacity. You have to know the specifications of your power sources such as how much power is provided, for how long they are available (wind vs solar vs alternator/generator) - how they charge and then of course such smaller things like how much space you have on your boat and of course cost.
As I want to renew the entire engery and storage system on our Five Senses, I did all these evaluations myself. Here I am sharing one of the steps taken: the calculation of power consumption.

All of this is clearly no rocket science: device list, power consumption (in watts or kilowatts), estimate how long the devices are operated in 24 hours (in hours) and then calculation of the consumption in ampere hours (Ah) taking into account your electrical system voltage. However, there are several different units used, so you might have to do some calculation. Here is an example table to show you how to do that:

LED lighting salon and cabins: 50 watts (rough estimate)
Operating time per 24 hours: 4 hours (estimated)
Daily consumption in kilowatt hours: (50/1000) * 4 = 0.2 kWh
We are using a 12 volts system
Conversion to Ah: 50 watts / 12 volts * 4 operating hours = 16.67 Ah

With the kWh and the Ah you are able to estimate your consumption per day. Usually, this includes on-board and navigation lights, electrical devices (hair dryer, laptop, coffee maker), navigation devices such as GPS and plotter including radar and autopilot, cooling boxes / fridge and freezer. This is the sum of your average, estimated consumption in 24 hours. It is obvious that an air conditioning system can hardly be powered by battery power. The navigation electronics created a bit of a surprise to me. Each device does not need a lot of electricity, but in total and over the sailing day and the many hours, there is a lot of overall consumption.

To estimate the battery storage capacity you need, you have to know the answers to these two questions:

How long has my stored electricity to last before I can recharge?
What kind of power storage = which type of battery do I want to use?

The first question is rather easy: This is heavily depending on your crusing plan and how long you are planning to stay off grid. Depending on where you sail, choices shoudl be made on energy sources. I collected some information and put this into another blog post to compare pro's and con's of the various alternatives.

For the second question again some background info is helpful: i.e. conventional lead acid batteries supply about 50% of their total capacity, lithium ion batteries can provide up to 80 or 90% of their storage capacity without being damaged. There are various other alternatives available and all come with their very individual specifications. Make sure you know what you need before buying any new batteries.

For our Five Senses (a 49 foot yacht in the Mediterranean and most frequently used during the day and somtimes during night), I calculated a daily consumption of around 330 Ah, or around 4 kWh. For LiIon batteries one can expect 80% of their capacity to become available, which translates into 412 Ah or almost 5 kWh of capacity per storage day. We currently have 400 Ah lead-acid batteries on board, so we are missing 130 Ah when 50% is removed, or in other words: after 14 hours without any charge, all power run devices are down.  330 Ah is a conservative calculation and an average, the power sometimes lasted longer, mainly because we also use the ship's diesel for docking and anchoring. But after a night at anchor, the batteries were mostly empty ...

Conclusion: new energy storage and energy sources are needed! Stay tuned ...

read more

Start der Saison 2019

We bought Five Senses June 2016 to then pick her up in Croatia the following October. Since then she has found a new home in the Marina Punta Gabbiani in Italy. I truly believe that with a boat it is the same as with a home on land: first you need to discover and put all the functional stuff in, but over time you really want to know the details and then develop and upgrade those step by step. And this is how I also plan maintainance and upgrades for the boat - step by step. Also because of the financial implications.

2017 was the year of the large scale changes, the teak deck had to be renewed, I ordered new sails and included a code zero (rigg adaptations were necessary) and some of the electronics, like the plotter had to go. Also the through hull fittings and sea cocks had to be replaced.

2018 the underwater paint had to be renewed and also new phrophylaxis against osmosis was due. A really great side effect was that this gained us 1 to 1.5 additional knots of speed in average. Furthermore we renewed the sprayhood and bimini and changed the color from deep blue to light grey. And we added some comfort via installing a freezer and of course our air-condition. On the safety side we renewed all the natural gas equipment, including the stove and oven.

2019 now is the year of refitting some of the instruments, making upgrades to the wooden pieces of the interior and renew energy production, storage and output. We also thought of renewing the cockpit cushions and I have started to install more of red light sources to equip us for night cruises. And not to forget, I started to install a smart glass film on my companion way door hatch.

Looking from the out-side

So the next posts will focus on the plans and also the execution of those plans in terms of upgrades, improvements or simple maintainance.

Last but not least, I started an instagram account to share more photos and to increase speed of posting. So if you are interested to see more pics feel free to subscribe - and like or comment! I appreciate to see your thoughts or responses.
Fair winds for all for you in 2019 and have a great saison!!


read more

Brijuni National Park – Safari Adventure in Croatia

No, this photo has not been taken during a Safari in Africa, it is indeed showing a Zebra feeding on the island of Brijuni. This piece of land is part of the Brijuni Islands formed by a group of fourteen small islands in the Croatian part of the northern Adriatic Sea. The largest island, Veliki Brijun Island (also known as Italian: Brioni Grande or Croatian: Veli Brijun), lies 1 mile off the coast, in close proximity to Pula. Today, the islands are a holiday resort and a Croatian National Park.

The history of this place is as fascinating as is its fauna and flora: In 1815 the islands became part of the Austrian Empire and a naval base was bulit nearby, in the harbour of Pula. Until today, you can visit the remainants of fortress, "Fort Tegetthoff," on Veliki Brijun Island Island besides other fortifications. The pictures below show the fortress in the city of Pula, where you can also visit one of the biggest roman theaters that are still preserved in Europe.

In 1945 Brijuni became part of former Yugoslavia and President Marshal Josip Broz Tito made the Brijuni Islands his personal State Summer Residence. Slovenian architect Jože Plečnik designed a pavilion for Tito. According to Wikipedia, almost 100 foreign heads of state visited Tito on his islands, along with film stars including Elizabeth Taylor, Richard Burton, Sophia Loren, Carlo Ponti, and Gina Lollobrigida. Tito died in 1980, and by 1983 the islands were declared a National Park of Yugoslavia and access was restricted.

In 1991 Croatia gained independence and made the Brijuni Islands an International Conference Center (see Brijuni Agreement). Four hotels on Veliki Brijun Island were re-opened, as well as a Safari Park, which holds animals given to Tito, including Indian elephants. However, there are a lot of further animals like donkeys, rabbits, peacocks, ostriches and many more.
But that is still not all, what the islands offers: besides the stunning scenery, you can see stone formations that look like dinosaur footprints. And the National Park claims that these are actually real footprints - I can't still believe it.

Apart from the younger history, this was also a settlement at the time of the Roman empire. Thus you can see former buildings, like houses, churches or pools. Parts of these are under water today and you can view them with your snorkel gear. There is also an underwater snorkel trail located in one of the beautiful bays. And the water is refreshing and cristal clear.

Last but not least, just beside the lovely boat-house, which hosts a museum of the National park, there is the Hotel "Neptun". It hosts a Restaurant, which we love to visit. Great local specialities are offered at top level service quality.

You can visit Brijuni simply by coming wiht the ferry from Fazana, a small port village just in opposite of the main island. Or, preferably, you come on your own keel. The smal harbor hosts a hand full of yachts, even at bigger sizes. The fee to stay over-night is charged for 24 hours and it includes the tickets for the national park. Still, staying here has it's price and this is maybe the most expensive docking space here in the northern med. However, we feel those 200 Euros are well spent, given the uniquness of this island.

read more

Covering our companion way hatch with smart film


Being moored in the marina with the stern to the dock is super convenient for getting on and from the boat. However, especially at night time with the salon iluminated, privacy can be an issue if you have a transparent door hatch for your companion way. And this is what we have on Five Senses. Honestly, I am not a fan of people staring at me when I am in my pyjama's reading a book on the salon's bench or sitting over the weatherforecast of the next day.
So I thought about covering the plexy-glass door with some opaque film, like I did in the bathroom windows. But this would have caused some protest from the children, as they love looking out the door-way when the weather is bad outside. They can spend hours watching the rain coming down and when heavy winds hit us in the marina.

097A2619Luis is watching the rain from inside

So I kept thinking and watched out for some other solutions. And you will never guess how I found my final remedy: in a bathroom of a restaurant in Brussels. There, they had installed a so called PDLS film, or, smart film to shielt their toilets from views from the outside. When the bathroom doors was unlocked, you could see inside. But after turning the door lock, the entire cabine became opaque. What a fancy gimmick! Besides the originality of that idea, it was huge fun watching the shocked faces, when people came in, looking for bathroom facilities and then discovered the "fancy interior".

With some help from the internet I found out, that this was "smart film" or "switch glass" a kind of film that consists of micron sized droplets of liquid crystal dispersed in an optically isotropic polymer matrix. The technical term for this product is Polymer Dispersed Liquid Crystal (PDLC). The working principle is rather easy, without current applied to the film, the liquid crystals are dispersed randomly and thus, light cannot pass through. After energizing the film with around 60V AC, the crystals align in a structured way and the film becomes transparent. So why not trying this on the boat?
Via Alibaba, I found a company called Groupeve, located in China producing their "magical smart film". They are shipping worldwide from their production in Sichuan. And their service, support and product quality are simply outstanding. I was in touch with one of their staff "Amanda" via What's App and they really made sure that first the smart film fitted the right dimensions and, that I was prepared to install it correctly. They even sent over pictures from the production to make sure all was perfectly right. You can see the paper blue print I had sent them. They used it to check the perfect fit.

Still, it took two attemtps to get the right size of the film to our boat. But it was really my fault as I had not sent the correct dimensions first. So my tip to those who might be trying to do the same thing: take a kind of blue print, measure everything twice and make sure you send over some pictures to be absolutely sure that you get what you need. You will also need to think where to attach the electric cables for applying the current.

First time, I thought I could cut out small pieces to make the film fit, which was not true at all. I totally destroyed the film. So again, make sure you sent the producer the 100% accurate measures so that they can prepare the film for you. Do not try to cut it on your own.

Groupeve will send a perfectly protected and well packed kit for installation. It includes a guide, soft towels for application and some smaller film pieces for practise. Another learning: use these parts for practising, as application of the smart film is not easy when you do it for the first time. And I am not saying that its a tough thing to do - just practise once and you will be fine. Groupeve even provides a short video instruction how to remove bubbles that might remain after attaching the self-adhesive smart film.

Another necessity is that you have a 100% clean and dry surface before you start attaching the smart-film. Every micro-hump will appear as a bubble. And even after cleaning the door several times, still, I found a hair then between the plexi-glass and the film. So I had to detach the film partly, remove all dust again and re-attach, which went fine. In my case there where several scratches, that I could not remove at all. But they did not seem to cause any issues.

The final result looked pretty nice, I felt. However - and you see I am not a DIY genius - I could not find the electric equipment anymore. I searched the entire boat for hours, but could not remember, where I had put it. Finally, I found it - back home, in the cellar. So I will write another post as soon as I am back in Italy again, to show you the final results including the electric installation.

read more

Einbau Klimaanlage

Seit dem Kauf unserer Five Senses habe ich nun schon einige Verbesserungen vorgenommen: Rigg Upgrade, neue Segel, das Unterwasser-Schiff wurde saniert, den Propeller habe ich gewechselt, neue Elektronik hat Einzug gehalten, wir haben ein Radar an Bord, das Holzdeck musste vollkommen erneuert werden usw., usw. - Bisher hat meine Crew das entweder mit Schulterzucken zur Kenntnis genommen, oder, ich habe Kritik einstecken müssen, denn man hätte das Geld ja auch anderwertig bestens einzusetzen gewusst. Der Einbau einer Klimaanlage an Bord hat aber eine vollkommen neue Reaktion bewirkt: Wertschätzende Dankbarkeit!
Eine zweite Reaktion möchte ich hier wiedergeben, die wir in Novigrad erlebt haben: Unsere Stegnachbarn hatten sich erkundigt, warum denn ständig Wasser aus unserem Boot lief. Rasch war erklärt, dass dies eine Umwälzpumpe für die Klimaanlagen-Kühlung wäre. Ich lud die hoch-erstaunte Crew unter Deck ein und dort hatte es im Unterschied zu den 38° Grad Außentemperatur (bei 70% Luftfeuchtigkeit) angenehme 28° Grad Raumtemperatur. "Das ist wahrer Luxus!" entfuhr es unserem Nachbarn und eigentlich hätte er unseren Salon gar nicht mehr verlassen wollen. Denn draußen war es eben brüllend heiß.
Und ich denke diese Aussage bringt die Essenz auf den Punkt: Eine Klimaanlage erhöht den Komfort an Bord schlagartig um das zig-fache. Aber es ist natürlich nicht alles Gold was glänzt und man muss ein paar Kompromisse in Kauf nehmen bzw Überlegungen anstellen, bevor man sich dazu durchringt solch eine Anlage nachzurüsten.

Stauraum und Kühlkapazität:
Je nach Stärke eines Aggregats braucht es einen definiert großen Platz für den Einbau. Es ist aber nicht nur der Platzbedarf für den Kompressor zu beachten, man muss auch eine Umwälzpumpe für Kühlwasser, ausreichend dimensionierte Durchlässe für die gekühlte Luft, die Absaugung des Kondenswassers und zusätzlich benötigte Kabel und Elektrik mit einkalkulieren. Eine der wesentlichen Entscheidungen zu Beginn eines Nachrüstungsprojektes ist daher, welche Räume klimatisiert werden sollen und mit welcher Aggregatstärke man rechnen muss. Als grober Richtwert sollten für eine kleine (Bug-)koje ca. 3.500 BTU Kühlkapazität berechnet werden. Ein Salon auf einer ca. 45 Fuss großen Yacht benötigt 9.000-16.000 BTU. Die Dimensionierung ist auch von der Farbe des Bootskörpers und natürlich vom Segelrevier abhängig. Für größere Schiffe über 50 Fuss eigenen sich getrennte Einheiten besser als Kompaktanlagen.
Wir haben uns für ein Setup aus vier Kompakt-Aggregaten entschieden (2 x 3.500 BTU für die Bugkojen und 2 x 9.000 BTU für jeweils den Salon und die Achterkojen). Dadurch konnten wir die Kompressorgröße jeweils eher klein halten, die Lärmbelästigung somit gering und die Steuerbarkeit der Anlage ist sehr individuell möglich. Die kleinsten Geräte in den vorderen Kojen nehmen sogar so wenig Leistung auf, dass sie theoretisch von den Batterien gespeist werden könnten. Alle Klimageräte können kühlen und auch heizen. Somit ersparen wir uns in der Übergangszeit Elektroheizkörper und müssen auch nicht die Dieselheizung anwerfen.

Untertags ist die Geräuschentwicklung nicht so ausschlaggebend, aber in der Nacht möchte man sicher nicht neben einem laut brummenden Aggregat schlafen müssen. Die Ventilatoren sind heute zwar schon sehr leise und laufruhig, geräuschfrei sind sie aber bei weitem nicht. Diesen Umstand muss man bedenken, wenn man eine Klimananlage einbauen möchte, denn alle Komponenten erzeugen Geräusche und davon sollte man nicht überrascht sein. Wichtig, vor allem beim Einbau in der Nähe von Schlafräumen, ist die Schall- und Vibrationsinsolierung. Alle Schraubverbindungen haben daher Gummidämpfer erhalten und alle Installationsräume wurden schallisoliert.

Die Stromaufnahme unserer Aggregate beträg je nach Phase (Dauerbetrieb vs Start) 2 x 1,60 - 5,20 Ampere für die kleinen Geräte und 2 x 3,4 - 21,80 Ampere für die beiden großen Anlagen. Bei 230 Volt Spannung sind also 2 x 50 - 1200 Watt und 2 x 780 - 5000 Watt fällig. Unsere Anlage hängt an einem bis 32 Ampere abgesicherten Landstromkreis, der extra neu angelegt wurde. Bisher war die Elektrik für max 16 Ampere ausgelegt gewesen. An heißen Tagen und kleinen Marinas auf Inseln ist es uns immer wieder passiert, dass die Steganlage nicht ausreichend stark dimensioniert war, um den benötigten Strom in der Anlaufphase bereitzustellen. Da war es gut auf die kleinen Aggregate zurückgreifen zu können. Unter diesem Setup konnten wir in fast allen Marinas die Klimananlage betreiben.
Ein Betrieb ohne Generator und nur von den Batterien aus ist schwierig, aber theoretisch machbar. Die Bereitstellung von Energie über Solarflächen ist möglich, man braucht aber wirklich genügen Platz dafür. Außerdem muss man beachten, dass der Inverter den Spitzenstrom beim Einschalten bereitstellen können muss. Die Wynns unterhalten einen Blog/Vlog und beschreiben dort, wie sie in ihrem Wohnmobil und später ihrem Katamaran die Klimanalage mit Hilfe von Lithium Batterien betreiben. Bleibatterien gehören für mich daher zu einer auslaufenden Generation von Energiespeichern. Das etwas schrille Paar zeigt auch, wie sie den Spitzenstrom begrenzten und damit ihren Inverter schonen.

Zwei Installationen sind notwendig: Kühlwasser muss zu allen Aggregaten und vor dort wieder zurück ins Meer gempumpt werden. Dafür braucht es zwei zusätzliche Durchlässe, die auch entsprechend mit Seeventilen ausgestattet sein müssen, sofern sie sich unter oder nahe der Wasserlinie befinden. Außedem entsteht Kondenswasser und mir wurde dringend davon abgeraten dieses einfach in die Bilge abzuleiten. Viel zu leicht kommt es dadurch zu Schimmelbildung. Also muss auch eine Absauganlage geschaffen werden, die das Kondenswasser verlässlich nach aussen befördert. Unser Montageteam hat dazu teils sehr kräftige Abwasserpumpen verwendet, um auch bei Lage den notwendigen Durchflussdruck zu erreichen. Auch ist zu beachten, dass bei hohen Meerwassertemperaturen im Sommer der Temperaturunterschied gering ausfällt und damit die Kühlleistung des Meerwassers sinkt. Die Umwälzpumpe und die Dimensionierung des Schlauchdurchmessers müssen also entsprechend gewählt werden.

Unser Projekt, Zahlen, Daten, Fakten

  • Drei Servicebetriebe: Bootselektriker, Bootstischler und Bootsmaler waren beteiligt, um alle notwendigen Umbauarbeiten zu bewerkstelligen
  • 2 volle Wochen Arbeitszeit für 2-3 Mann Teams waren notwendig
  • Planung ca. 2 Monate, Umsetzung vor Saisonbeginn 2018
  • Kosten: rund 15.000 Euro für 4 Kühlgeräte und sämtliche Umbauarbeiten
  • Zufriedenheitsfaktor: 100% durch Planung und Umsetzung eines ortsansässigen und zuverlässigen Profi-Teams

Ich sehe mich durchaus als engagierten Bastler und scheue mich auch nicht vor größeren Projekten, aber dieses Mal habe ich mich gerne auf Profis verlassen. Zu viele Komponenten ergeben hier zu hohe Komplexität und Spezialwissen ist notwendig. Für mich ist so etwas kein DIY Unternehmen.

read more

Primary Color

Secondary Color