**4.1 Outboard electric motor**

The first specification we present is related to a marine outboard motor (electric boat), where the nominal speed of the propeller is 1750 rpm, with a reduction ratio of the transmission angle equal to 2.

The simplified specifications of the motor are as follows:


There is no need here to detail the EMAG sizing of the motor, which is conventional and does not fit the main purpose of this chapter. The following **Table 3** summarises all the main characteristics of the motor.

This first case of sizing shows that even with a relatively low nominal operating speed, it is possible to reach high specific performances where, in particular, the


**Table 3.** *Characteristics of the electric boat motor.* power density is higher than 1 kW/kg, without impairing the efficiency. The latter is a key performance in the case of electric boat where the nominal speed corresponds to a permanent operating speed because the vehicle regime is stable during the navigation.
