Power take off (PTO)

Author: Jonathan Vallejo

What is a Power Take Off?

It is common for boats to need power supply for certain auxiliary elements, such as pumps or compressors. Through the power take off (PTO) of the engine, it is possible to power these components without the need to resort to generators or auxiliary engines, this entails an improvement in efficiency.

Kit Power Take Off

In Line and Axial PTO

Depending on the laying of the load, it will be possible to differentiate between two types of PTO: in line and axial. When the load is placed on the engine shaft it is called in line PTO, while if it is placed perpendicular to it (due, for example, to space limitations in the engine room) it would be an axial PTO (the connection between the PTO and the load would be done by a strap).

In line PTO

With an in line PTO, it is possible to extract 100% of the engine power, while in the axial PTO, due to the mechanical limitation of the shaft, it is lower. Therefore, the power extracted with an in line PTO will always be higher than using an axial power.

PTO with pulley

Engine with no load / 80% of the engine power  

It is considered that a motor works with no load when the gearbox is not coupled and therefore the propeller is not in operation. This means that the boat is standing or at anchor. However, in this situation the motor may be in operation since energy is often required for other components of the vessel. Through the PTO it will be possible to supply energy to pumps, air compressors or alternators to generate electricity.

Sole Diesel PTO Kits

When the boat is sailing, the power for the PTO will be much lower than when the engine has no load. If the dimensioning of the propulsion system is correct, the propellers are designed to absorb approximately 80% of the engine power. In this situation, the remaining power until the maximum continuous power (MCP) is available to the PTO.

In case of using the PTO in a genset, the operation is similar: when the generator has no load the PTO will extract all the power, but when it works at 100% load, only the power margin of the engine up to the PMC will be available.


When choosing a PTO, it is important to know if the engine will work with or without load, what the load will be and what the PTO layout will be.

Sole Diesel guarantees an optimum operation with the kits available for its range of motors and generators whenever the product works below the limits established by the manufacturer.

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Basic Kit for engine maintenance during navigation

This post is also available in: Spanish

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