What is an outboard motor and how does it work?
With outboard motors, all components (engine, transmission, gearbox, propeller) function in one single constructed unit. This gives them an advantage over inboard motors, because they can be removed from the boat with little effort. The propeller at the bottom of the motor shaft drives the boat. Outboards can often be pulled or tilted at an angle, so that the underwater part is not damaged during transport or landing.
Which outboard for my boat? Classic petrol outboard or electric?
The first question to ask when buying an outboard motor is whether to go for an electric or classic petrol engine.
Why should I buy a petrol outboard?
Petrol engines are generally more powerful than electric outboard motors. These types of engine are better suited for use in waters with strong currents, or with larger inflatable boats. If you are planning on taking your inflatable boat over long distances, or want to go fast, a petrol engine is the better choice, as it can always be refilled with a fuel can, quickly and easily. In some regions, however, petrol engines are not permitted due to the noise they make, or there could be seasonal restrictions regarding their use that one should be aware of. Be sure to find out what the rules are for the area you are planning on using your engine in before buying one.
When is an electric outboard the right choice for me?
Electric motors are outboarders that run on battery power. They have to be charged with electricity from the main supply. Using an electric motor with a smaller inflatable boat up to 2.5 m is a great idea. The motors are quiet, emission-free and do not vibrate as much as petrol engines, so they are particularly suitable for use in areas where petrol engines are prohibited, for example in nature reserves, and because they’re so quiet, this makes them great for fishing. Most electric outboarders do not have a gear box, making them very light and low-maintenance. Electric motors require no oil, and mechanical wear is virtually non-existent. They have good torque even at low speeds. The high torque and superior efficiency of these engines make it difficult to compare them with combustion engines in terms of pure kW or horsepower. Torqeedo claims that the Cruise 2.0 electric outboard with 2,000 watts of input power is the equivalent of a 3,700 watt petrol outboard (5 hp).
Before buying an electric outboard motor, you should consider the distances you want to cover and the duration of use. These factors are obviously limited by the battery power. You should also keep in mind that charging and discharging the battery must be carefully monitored, as it is possible to damage the battery if it is fully discharged or over-charged.
Electric outboard test
The German magazine Segeln carried out an electric outboard motor test on three different engines for their 7/2020 issue, focusing on speed, power and noise level. To measure noise level, the e-motors were run at maximum power on land, with the results providing a good reflection of the noise level on the water. Testing the electric outboard motors for pulling force involved connecting the e-drives to a measuring device and measuring cell and slowly turning the tiller to maximum. Three measurements were taken for each of the three test engines. These were then averaged to give the final result for each outboard. A speed app was used to test the top speed and acceleration. In the test water there was no current. Tests were carried out with and against a strong and slightly gusty wind of approx. 3 Beaufort, and the final result was taken from the mean of the two tests. The Torqeedo Travel 1103 C emerged as the test winner from the electric outboard motor test. The other models tested were a Haswing Ultima 3.0 and an E-Propulsion Spirit 1.0 Plus motor. The test result shows that the Torqeedo Travel 1103 C has by far the highest pulling force of 340 N, is very quiet in comparison (78 dbA backwards & 96 dbA forwards on land) and has the most features.
Our SVB experts recommend…
|… a petrol outboard if you:||… an electric outboard if you:|
Which manufacturer should I choose for my outboard motor?
After you have decided on an electric or classic petrol outboarder, the next choice is the make. Our online shop is packed with petrol engines from Mercury, Suzuki, and Honda, and electric outboarders from Torqeedo and Minn Kota. Many of our customers have their favourite brand that they have sworn by for years. If this is the first time you are purchasing an outboard motor, you should first check the local service network of the individual manufacturers. This is because engines must be serviced every year so that they are covered by the warranty in the event of damage. The service network of the individual manufacturers can be found on the following pages:
Shaft length also depends on the choice of manufacturer. For example, a Honda outboard motor with a short shaft has a different length to a Mercury or Suzuki.
If you have an electric outboard motor, please note that the Minn Kota outboards in our range are not suitable for use in seawater. If you wish to use the motor here, you should always choose a Torqeedo motor. We can order Minn Kota models suitable for seawater on request.
How much power does my outboard motor need?
In our online shop, the respective power or thrust of each outboard motor is listed in the name of the engine. For example, the SUZUKI DF 2.5 S is a 2.5 hp engine with short shaft and the Honda BF10 LHU a 10 hp engine with long shaft. If you are looking for a suitable motor for use in inflatables, you will find the information "Motorizable up to XY kw / PS" as well as a maximum motor weight on the respective product pages of our inflatable boats. You will find an overview of all our inflatable boats with their maximum motorisation under more information.
The engine power you should choose depends on several factors:
- size and weight of your boat
- the number of people to be carried (weight) and the resulting total weight
- water current
For medium-sized inflatable boats of 2-3 meters, a 5 HP outboard engine is usually enough, if there is little or no current. For large inflatable boats of 4 meters or more, or smaller boats used in areas with strong waves or strong currents, more powerful outboard engines with 5-20 HP should be used.
Which outboards do not need a licence?
The power you choose for your outboard motor also depends on whether you have a boat licence or not. In Germany, people aged 16 or over may sail recreational boats up to a length of 15 metres without a licence in inland and lake areas, provided that the nominal power of the engine does not exceed 11.03 kW (15 hp) and that it is not used commercially. The only exception to this is on the Rhine, where international regulations require a licence for a net power of more than 2.68 kW (3.6 PS). In the maritime sector, recreational craft of up to a maximum net power of 3.68 kilowatts (5 hp) may be operated without a recreational craft licence, irrespective of age, i.e. even under the age of 16, as long as it is not for commercial use. This regulation not only applies to smaller boats with outboard engines, but also to motorboats or sailboats with built-in diesel engines.
What shaft length should my outboard have?
Most outboard motors are supplied with different shaft lengths. Short shafts (15") and long shafts (20") are common. In our online shop you can easily identify long or short shaft engines by their title. An L in the title, such as in the Honda BF 10 LHU stands for long shaft, an S in the title, such as in the Honda BF 2.3 SCHU, stands for short shaft. Whether you need an outboard motor with long or short shaft for your rubber dinghy is determined by the height of your boat's transom. The outboard motor must be mounted so that the plate above the propeller (anti-cavitation plate) is a few centimetres below the waterline of the hull. The distance between the engine support on the transom (upper edge of the transom) and the lower edge of the hull must be measured.
You can determine the required shaft length based on the measured length:
- Short shaft motor: approx. 38 cm transom height (inflatable boats up to approx. 3.80 m length)
- Long shaft motor: approx. 50/51 cm transom height (inflatable boats over 3,80 m length)
For all inflatable boats that are in our online shop, an outboard motor with short shaft is perfectly sufficient. You should choose an outboard motor with a long shaft only for our SEATEC GT Sport 410 with fixed hull.
Mounting an outboard motor with a shaft length that is not appropriate to the boat's transom worsens the sailing performance of the boat. The outboard propeller must be completely underwater. If not, the outboard engine will suck in air and it may be damaged. If it is too deep in the water, efficiency, handling and consumption levels will change. In the worst case, it may touch the ground and damage the propeller or underwater part.
Which type of starter should I choose for my outboard motor? Manual or electric start?
The final step is to decide on an outboard motor with a manual or electric start. Smaller outboards are often equipped with a manual starter and a steering tiller that swivels the engine on a bracket around its vertical axis to port or starboard. A small tank is usually integrated into the engine housing. In addition, separate outboard tanks can be connected, which are then often equipped with a level indicator and a reserve fuel chamber.
More powerful outboards are available on request with electric starters, usually with chargers for the starter battery and for supplying power to onboard consumers. If you opt for an outboard motor with electric start, you also have the option of choosing a motor with remote control.
When making your choice, you should bear in mind that outboard motors with tiller and manual start are lighter in weight. E-start and remote steering add weight to outboards.
FAQ with product recommendations
Do SVB outboards have an external tank connection?
Our 2.3, 2.5 and 3.5 hp outboards do not have an external tank connection. Our 4, 5 and 6 hp outboard engines have an external tank connection. But the tank is not included. Our 8 hp outboards have an external tank connection. A tank and matching hose kit are included.
I wish to purchase an outboard motor with remote control, can I get one from SVB?
Yes, on our homepage we also offer a number of outboard motors with remote control, you will find the links below. The remote control box is included with these outboards. Mercury outboards also come with a tilting axle mount. For Honda outboard engines this bracket must be ordered separately. Our Torqeedo outboard motors with remote control are delivered with remote throttle lever, but without connections to the remote control. Other outboards with remote control or matching conversion kits can be ordered on request.
Outboard motor with remote control
Are control cables included with the outboard motors?
No, control cables are not included with the outboard motors and must always be ordered separately.
Are the outboards supplied with engine oil?
Mercury outboard engines are supplied with 1L 10W30 oil. The outboard motor only needs to be replenished on delivery. Honda and Suzuki outboards are delivered without engine oil. The amount of oil required varies from engine to engine and should be specified in the respective operating instructions. If you have any questions, please contact our customer service.
Written by our SVB (technical) experts
Our team of SVB technical experts is there to give our customers professional advice on all matters relating to technology on board. Their expertise is the result of regular training and many years of experience.