M200 Brushless Underwater Motor


The M200 Motor is a rugged brushless underwater motor for use in the ocean and in harsh environments. It can be used to build custom thrusters, actuators, pumps, sampling devices, and more! This motor cannot be used inside the T200 Thruster – it is for other subsea applications.

The new R2 version (as of September 2019) has a stainless steel base, solid overmolded stator, and 1 m (40 in) of cable.

Notice: We’ve run into some unanticipated production issues after releasing this product and we’ve put production on hold until we can resolve that.

Out of stock

HS Code: 8501.31.4000

Product Description

The M200 Brushless Motor is a brushless motor designed to operate underwater in harsh environments like the ocean. It shares some of the same internal components as the T200 Thruster and has the same electrical performance but doesn’t have the plastic nozzle or other components. The M200 can be used for all sorts of powered underwater devices including custom thrusters, surface vessel propulsion, pumps, actuators, gear drives, and more.

The M200 Motor comes with a 1 m (40 in) cable pre-installed and sealed to a stainless steel 316 base that resists corrosion in harsh environments. The motor windings are completely encapsulated, providing high electrical resistance to the water and corrosion protection. The rotor is the same as the T200 Rotor and shares the same protective coatings and load mounting options.

This motor is a sensorless three-phase brushless motor and requires an electronic speed controller (ESC) for operation, just like our thrusters. It is compatible with most sensorless brushless motor controllers with sufficient power output.


  • Threaded M3 mounting holes spaced 19mm apart
  • Operates under extreme pressures and depths
  • High-performance plastic bearings that don’t corrode
  • New in R2: Stainless steel base
  • New in R2: Solid overmolded stator protection
  • New in R2: 1 m (40 in) of pre-installed cable
  • New in R2: Inline and flush mounting cable exit options

The M200 can be used in a wide array of applications but we have a few usage examples to demonstrate it’s performance and flexibility. Below is a 3D printed centrifugal pump that turns the M200 into a powerful underwater pump that can be used for debris removal, cleaning, sample collection, or anywhere a pump might be used. You can find more about this project on the forums along with the 3D files and discussion.

M200 Pump Motor
M200 Pump Motor

3D printed centrifugal pump with the M200 motor.

The M200 is also in use on a set of custom thrusters that Blue Robotics designed for the Woods Hole Oceanographic Institution’s Mesobot vehicles. These thrusters are incredibly specialized with a large propeller (56 cm!) that turns very slowly through an 8:1 gear reduction to minimize water disturbance while maneuvering the Mesobot vehicle. The vehicle will track small organisms as they move through the water column and these thrusters are an essential part of accomplishing that.

The WHOI Mesobot vehicle in action, powered by custom thrusters built with the M200 Motor.

The WHOI Mesobot vehicle in action, powered by custom thrusters built with the M200 Motor.


  • 1 x M200 Brushless Motor with 1m of pre-installed cable


Mounting Hole ThreadsM3 x 0.5
Weight in Air174 g6.14 oz
Operating Voltage6-26 Volts
Max Current30 amps
Max Power600 Watts
RPM/V (Kv Rating)490 RPM/V
Torque10.5 Nm4.5 in-lb
Depth RatingTBD

1 Torque is provided as the theoretical maximum based on the motor design. This torque can only be achieved at all speeds with the proper motor controller. These numbers have not been validated experimentally.

The M200 may be used at no greater than the following values (whichever comes first): 30A, 26V, 600W. Exceeding these values will cause permanent damage to the motor.

2D Drawings

M200 2D Drawing

3D Models


Revision History

17 September 2019

  • R2 – Initial Release

Quick Start

1. Connect motor wires to ESC and connect the ESC to power and a PWM signal source (microcontroller, radio control servo output, ect.)

2. Send a signal and the thruster will start spinning. That’s it!


Do not operate the motor for extended periods out of water, the bearings are lubricated by the water. Vibrations and noise will be greater when dry.


M200 Motor Usage Guide

Learn about different installation techniques, maintenance and troubleshooting for the M200 motor!

M200 Motor Disassembly/Re-Assembly

Quickly disassemble an M200!


BlueRobotics Forums – Thrusters and Motors