Comparison Haswing Osapian 85lbs Protruar 2.0 vs Fisher 86

The maximum operating power of the outboard motor, expressed in horsepower.

Horsepower (hp) has traditionally been used primarily to refer to the power of internal combustion engines, including gasoline engines (see "Engine type"). However, in outboard motors, these units are also used for electric models (see ibid.). This is due to the fact that the majority of gasoline engines are on the market, and boat manufacturers prefer to indicate the maximum recommended engine power in “horses”.

The general patterns when choosing outboard motors in terms of power are as follows. On the one hand, a more powerful unit will allow you to develop more speed and is better suited for a heavy boat (see "Maximum boat weight"). On the other hand, weight, dimensions, cost and fuel/energy consumption also directly depend on power. Therefore, it does not always make sense to chase the maximum performance.

In addition, the choice of motor for maximum power also depends on the characteristics of the craft on which it is planned to be used. It is not worth exceeding the recommended power stated in the specifications — firstly, the boat transom may not be designed for a heavy large-sized unit, and secondly, the boat itself may not be suitable for acceleration to high speeds. There are also more specific recommendations. For example, from the point of view of efficiency and safety, the engine power at the level of 60 – 80% of the ma...ximum specified in the characteristics of the boat is considered optimal. Lower values may be useful if economy and low noise level are important to you, and higher values if high speed and acceleration dynamics are key points.

There is one more specific point associated with this parameter: most often, the characteristics indicate the power output directly to the propeller, however, some manufacturers (mostly east european) can go for a little trick, indicating the power on the main motor shaft. When power is transferred to the screw, losses inevitably occur, so the useful power of the motor in such a case will be less than claimed. Thus, when choosing and comparing, it's ok to clarify what kind of power is meant in the characteristics — on the propeller or on the shaft.

The maximum operating power of the outboard motor, expressed in kilowatts.

The practical value of motor power is described in detail in “Maximum power" is higher. Here we note that the kilowatt (derivative of watt) is just one of the units of power used in fact along with horsepower (hp); 1 HP ≈ 735 W (0.735 kW). Watts are considered the traditional unit for electric motors (see "Engine Type"), but for a number of reasons, outboard motor manufacturers use this designation for gasoline models as well.

The type of cooling system provided in the design of the motor.

— Air. Cooling effected by contact of air with heating parts of the engine. Air cooling systems are extremely simple, they do not require the construction of complex circuits through which liquid must circulate — a fan is enough (and some models even get by with passive radiators — characteristic ribbed protrusions on heating parts). Another advantage is the ability to work effectively regardless of the presence of impurities in the water, which allows such engines to be used quite effectively in polluted and overgrown water bodies. On the other hand, the efficiency of such cooling is low, and it is suitable only for low power units — up to 15 hp. Also note that this option is usually indicated for electric motors (see "Motor type"): although the electric motor in them is often under water and cooled by water, not air, the key point in this case is the absence of a special cooling circuit in the design.

— Water. Cooling, carried out, in accordance with the name, with the help of water. Note that we are not talking about liquid, but specifically about water cooling: the water necessary for the operation of such systems does not circulate in a vicious circle, but is taken overboard and discharged there after passing through the circuit. This is the main difference between boat cooling systems and "land" ones. If we compare this type of cooling with air, then...water systems are more complicated and expensive, but much more efficient and suitable for motors of almost any power. Note that in inexpensive low-power units, water is supplied by gravity, due to the pressure created by the screw, and in more advanced models a special pump is used.

The highest current drawn by an electric outboard motor (see Motor Type). This parameter is necessary for the successful selection of the battery from which it is planned to power the motor: any battery has limitations on the maximum discharge current, and overloading (exceeding this current) is fraught with various troubles — from battery deterioration to fire or even explosion.

In addition, power consumption allows you to estimate the operating time of the motor from a particular battery. For example, if a suitable battery has a capacity of 60 Ah and the maximum motor current draw is 30 A, then at least 60/30 = 2 hours of operation from a fully charged battery can be expected.

The recommended weight of the boat on which the motor is planned to be installed. In this case, the total weight of the vessel is meant, taking into account both the hull itself and various equipment, as well as luggage and passengers. Note that this indicator is just a recommendation, and not a strict prescription — usually, the motor works quite acceptable on both lighter and heavier vessels. However, it is believed that it is when the weight of the boat matches the recommended indicators that the engine turns out to be the most efficient and safe; with less weight, you often have to “hold back” the power of the engine somewhat, and with more, the vessel can move more slowly than we would like.

As with the maximum thrust described above, the recommended weight is usually indicated only for electric motors (see "Motor type").

The gear ratio describes how fast the propeller of the outboard motor rotates relative to the speed of rotation of its shaft. For example, a gear ratio of 2 means that for each revolution of the shaft, the screw, in turn, makes two revolutions (that is, it rotates twice as fast). In modern outboard motors, this parameter, in fact, is purely reference, because. the practical characteristics of the unit (power, traction, etc.) depend on many design features and are practically not related to the gear ratio.

The design of the propeller supplied with the appropriate type of outboard motor (see above). In this case, the simplest division is used — by the number of blades.

This indicator actually refers to reference, and not practically significant, because. the practical characteristics of the propeller depend not only on the number of blades, but also on their shape and length, and a number of other indicators (power, thrust, etc.) affect the general characteristics of the motor. In addition, manufacturers tend to select propellers based on the best match with the desired capabilities of the motor.

The types of gears provided in the design of the outboard motor are, in fact, the direction in which it can move the boat.

— Front. Standard gear for forward movement. Available in all outboard motors without exception, by definition.

— I'm neutral. In this case, neutral gear means the mode of operation of the motor, in which its shaft rotates idly, without transferring rotation to the propeller or water jet. Thanks to this, you can completely remove the thrust without turning off the motor and without lifting its “leg” out of the water. Considering that starting after a shutdown can be a rather troublesome procedure (especially if you have to do this often), and removing a spinning propeller from the water is generally undesirable — having a neutral gear is a very useful feature, and most gasoline engines (see "Engine type") have this mode. But in electric models (see ibid.), stopping and starting do not constitute a problem, so the role of the “neutral” in them is played by turning off the power and completely stopping the motor (and the neutral gear itself is not indicated in the specifications).

— Back (reverse). A mode of operation in which the engine pulls the entire vessel backwards; in propeller motors, it is implemented by rotating the propeller in the opposite direction, in jet engines, by using reverse dampers. The reverse functi...on greatly facilitates both manoeuvring in narrow spaces and emergency braking on the water, so it is found in the vast majority of gasoline engines and almost all electric ones.

Note that electric motors (see “Engine type”) can have several gears of the same type — for example, 5 forward and 3 reverse. In such models, each "gear" is a separate switch position corresponding to a certain engine power. In gasoline engines, power control is carried out smoothly, using a throttle, so they have less than one gear of each type.

The height of the transom of the boat for which the motor is designed. This parameter is also called “leg length” (meaning, of course, the “leg” of the motor itself, and not the boat).

The transom is a part in the stern of the vessel, designed to mount the motor. The length of the motor leg must match the dimensions of the transom, otherwise the propeller will be at an off-design depth, which is fraught with problems in operation and loss of power (regardless of whether it is too deep or too shallow). The height of the transom, usually, is indicated in the documents for the boat itself — it is from these data that one should proceed when choosing a motor according to the length of the leg.