Submersible pumps are always:

Submersible pumps are typically directly driven for several reasons relating to their operational design and efficiency. In a directly driven setup, the pump's motor is integrated with the pump itself, allowing it to function efficiently while submerged in the fluid being pumped. This direct coupling reduces the potential for mechanical failures and increases reliability since there are fewer components involved that could introduce failure points.

Additionally, direct drive systems provide better torque transmission, leading to improved performance, especially in applications that require the pump to operate under varying pressures or capacities. The compact design of directly driven submersible pumps allows them to operate at greater depths and in confined spaces where indirect coupling or other drive methods may not be feasible.

The other options, such as indirectly coupled, belt driven, or gear driven, introduce complexities and potential weaknesses that are generally avoided in submersible applications. Indirect coupling can lead to increased vibration and wear, while belt and gear drives would require additional maintenance and could create issues with alignment, especially in submerged conditions. Therefore, the choice of direct drive aligns well with the operational demands and environmental conditions faced by submersible pumps.