Electric power supply on yachts
An on- board network comparable to that in cars or trucks is responsible for the electrical energy supply on yachts . In contrast, the electrical energy supply on commercial ships is designed to be much more complex and efficient.
Framework
While the engine with a connected alternator is always available for the power supply in motor boats, at least during the journey , sailing yachts have to get along over long distances without any energy supply from the main engine. While sailing, the electrical consumers are fed by accumulators. The more luxurious the yacht is furnished, the higher the power consumption. As a minimum, the navigation equipment ( GPS , chart plotter , wind measuring system ), the radio and, at night, the lights must be supplied with energy. Electric winches, Pressurized water pumps, autopilots and refrigerators are common on seagoing yachts today, but they consume a lot of energy.
With sport boats, relaxation is often the focus. Constant engine noises and exhaust gases are annoying, especially at anchor or in harbors. For reasons of environmental protection and to avoid nocturnal noise in marinas where many people spend the night on their boats during the season, it is often forbidden to leave the machine running longer than absolutely necessary. At least the refrigerator must be able to operate when the ship is moored, otherwise food will spoil quickly, especially in summer. It is therefore essential that the power supply can be maintained for a long time without the combustion engine being operated.
Opportunities to generate energy
If only daily stages are sailed, the batteries can usually be recharged with shore power in the ports (see below). It is possible to leave the ship's diesel running for a few hours a day to charge the batteries - on motorboats it will then always run. In comparison to their basically unlimited range, sailing boats have a limited capacity for fuel, so that this is only possible to a limited extent over long distances - moreover, the operation of the diesel at greater heel could damage it because the lubrication would then fail. Boats that want to cover long distances independently are therefore often equipped with at least one additional system for generating energy.
Alternative energy sources can be:
- Solar panels - very efficient, especially in the warmer regions popular with sailors. They work silently. But they need a significant area in order to make a noticeable difference in the energy balance.
- Wind generators - very popular on cruising yachts as wind is needed for sailing anyway. These also work at night, when the sun is low at high latitudes and at anchor, but are often relatively loud and their output (50 to 100 watts) is usually low.
- Hydrogenerators - especially common on high performance racing yachts. Hydro generators are comparable to wind generators that are plugged into the water. They use the boat speed to generate energy. Alternatively, a hydrogen generator can also be connected directly to the shaft of the boat propeller. The disadvantage is the relatively complicated installation and the fact that they do not work below a minimum speed.
- Fuel cells work quietly. Direct methanol fuel cells are operated with a methanol-water mixture that is sold in canisters.
Often blue water sailors use a combination of the options listed here, which can then complement each other.
Technical implementation
12 V electrical systems are common on sports boats, and in some cases 24 V on larger boats. This means that components from the automotive sector can be installed, which saves costs. For example, radios and many light sources are identical to those in cars.
The picture on the right shows the electrical system of a simple sailing yacht. In the center of the energy supply is the main machine with the alternator and the accumulators. As a rule, there are two battery banks (actually always accumulators , but colloquially one speaks of batteries ), one with a lower capacity exclusively for starting the engine and one for all other consumers. Since the two battery banks are separated by a switching diode , it is ensured that the machine can still be started even after the consumer batteries have been completely discharged, for example due to a forgotten light (safety aspect!). The batteries can be disconnected individually with a battery main switch to prevent unauthorized driving away or to prevent further damage or fire in the event of a short circuit. AGM or lead gel accumulators are mostly used as accumulators because they function in any position, do not form any explosive gases and can also withstand deep discharge. Lithium-ion batteries as a 1: 1 replacement for old AGM batteries, which also have the necessary battery management system built in, are now available (2020), but they are still very expensive. Their advantage is a much higher capacity with the same weight.
The main supply lines to the batteries are shown in bright red. On the one hand, this is the thick cable to the starter motor of the machine, which must be designed for more than 100 amperes with the associated return line, and on the other hand, the charging cable from the alternator to the batteries and the charge isolating diode for the consumer batteries. The significantly thinner lines to the individual consumers, which can be switched on and off via a central switch panel, are shown in dark red. In particular, the interior lighting can be individually switched directly on the lamps. The control panel of a sailing yacht is usually located near the navigation table, where the most important electronic aids are installed right next to it; this includes the marine radio and a GPS receiver . In contrast, these switches are located on a motor yacht within reach of the helmsman.
Data lines are shown in blue; depending on the technology used, these can be designed as a bus or as a star connection . Communication standards such as NMEA 0183 or NMEA 2000 are widespread . The wiring harness drawn in green represents the engine control system. The mostly analog signals (marine diesel engines often use old technology) report problems with the engine, such as overheating or lack of cooling water, in the cockpit by means of lamps and acoustic problems. The protective earthing of all metallic parts, especially the rig, which is also required for lightning protection, is not shown. The shore power supply is also not shown. The batteries can be recharged with a charger through a shore power connection.
| number | designation | Remarks |
|---|---|---|
| 1 | Machine with alternator and starter | Marine diesel engines are common, but outboard engines can also be started electrically. |
| 2 | Engine starter battery | Only used to start the engine |
| 3 | Consumer batteries | A power diode prevents the starter battery from being drained if consumers are not switched off. Since the main switches usually remain switched on as long as someone is on board, this could lead to more problems than in the car |
| 4th | fridge | Usually, like refrigerators in houses, compressor cooling is used because it is more efficient than cooling via the significantly cheaper Peltier elements . |
| 5 | Transducers for log and echo sounder | The measuring probe for the log sits in the foredeck in front of the keel and measures the boat speed. The ultrasonic measuring unit for the depth gauge is now often integrated in the same device. |
| 6th | Cabin lighting | Ceiling lamps in all cabins, these can be switched individually with switches on the lamps themselves. |
| 7th | Bow light (s) | Two-color lantern on the bow or two single-color lanterns just behind |
| 8th | Steamer or toplight | The so-called "steam light" for machine travel is located at a height of about 2 m on the mast |
| 9 | Anemometer | The transducer for the wind speed and the (apparent) wind direction is located in the mast top |
| 10 | Anchor light | The anchor light is on the top of the mast |
| 11 | VHF marine radio | The marine radio is located by the navigation table. It is connected to a GPS receiver so that the current position can also be transmitted in the event of a DSC distress alert . The associated transmitting antenna is located on the top of the mast. |
| 12 | Electrical distribution (includes switches for each circuit) | Central switching point for all circuits. Also contains the circuit breakers for the circuits (or older boats fuses for it). |
| 13 | Navigation displays (plotter, speed, wind direction, depth ...) | In the cockpit, easy to read for the helmsman, there are displays for navigation. Including the display from the wind measuring device (wind strength and direction), the speed through the water and now often a chart plotter . Depending on the expansion stage, these devices can be found both in the cockpit and below deck for the navigator. |
| 14th | Autopilot; a tiller pilot on this little yacht. | Autopilots can relieve the crew of a lot of work, but they can use a lot of electricity. |
| 15th | Stern light | The white stern light is switched on or off together with the bow light. |
| 16 | Machine control and display | The controls for the engine and the throttle are located next to the steering wheel. |
Systems are also available for very modern yachts that control all electrical consumers via a bus system. The lights, for example, can then be switched on and off on every display device in the ship (e.g. on the plotter in the cockpit and on the navigation table). This reduces the total number of cables that have to be laid individually, but increases the technical effort in terms of software and necessary maintenance or modification work.
Energy supply in the port
Thus in marinas charged for pleasure boats batteries and boats can also be extended periods of time without failure of the refrigerator, including shore power socket outlets of the standard range. On the jetties, 230 V sockets (mostly with so-called caravan plugs ) are attached at regular intervals , to which the boat's charger is connected with its own cable. This allows the ship's batteries to be recharged without the engine running.
literature
- Seamanship. Yachting manual. 30th edition, Delius Klasing Verlag , Bielefeld 2013, ISBN 978-3-7688-3248-9 .
Individual evidence
- ↑ a b Scheme according to: seamanship, manual for yachting. 28th edition. Delius-Klasing-Verlag, Bielefeld 2008, ISBN 978-3-7688-0523-0 , p. 104.