T100 Thruster Usage

By Rusty and Adam


The T100 is world’s first affordable underwater thruster designed for marine robotics and the future of ocean exploration.


Always practice caution when you’re working with electricity in water and with the spinning blades of the propeller. Keep body parts away from the thruster inlet and outlet to avoid injury.

Important Notes

Do not operate the thruster for extended periods out of water. The bearings are lubricated by the water and vibration and noise will be greater when dry.

Do not operate the thruster for extended periods (more than a minute) at full throttle in water. If not allowed to cool periodically, damage can occur. We recommend our T200 thruster for long period high throttle use cases.

The thruster can handle saltwater and sandy environments pretty well, but it does not get along with seaweed. Avoid sucking seaweed into the thruster to avoid damage.

Most threadlockers are not chemically compatible with with polycarbonate, and will damage the thrusters if used on any of the screws. Refer to the documentation and chemical compatibility notes of your threadlocker of choice for more information.

A slight clicking noise is normal, especially when operated dry. It is caused by slight movement of the shaft in the plastic bearings.


The T100 Thruster is easy to install in many different applications. It was designed with versatile mounting options for a variety of different applications. It includes a counter-rotating set of propellers. Check out the tutorial on how to change the propeller.

Private: Changing a Propeller
Learn how to quickly change a propeller on a T100 or T200!

Mounting Options

The T100 Thruster has several mounting options. The nozzle has four mounting holes that can be used to secure directly to vehicle.


Occasionally, these holes may not be convenient or it may be difficult to secure the screws. In this case, the mounting bracket may be a better option. The mounting bracket is secured to the thruster through the four screw holes. It can be mounted in two different orientation as shown below.

You Will Need

You will also need:

  • 1 x #1 Phillips head screwdriver (BlueROV2 kit)

Thruster with bracket in front/back orientation:


Thruster with bracket in side to side orientation:


The mounting bracket also includes a guide hole that can be drilled out with a 1/4″ (6.5mm) drill bit to allow the wire to pass directly through the bracket.

Which mounting option you choose depends on your application.

How to Cut and Strip the Cable

The thruster comes with a tough urethane-jacketed cable. This is great for use underwater, but it can be a little difficult to remove the jacket from the wires if you want to cut the cable to a shorter length. During production, we use a thermal wire strippers, but the jacket can also be removed with a razor blade or hobby knife. Check out the cable stripping tutorial with pictures here.

Cable Stripping
Learn how to properly strip cables for use with WetLink Penetrators!


The thruster requires a brushless electronic speed controller (ESC). Checkout our Basic ESC product page for more information.

Connecting to an External ESC

The thruster has a cable containing three wires. These three wires must be connected to the three motor wires on the electronic speed controller (ESC). The order does not matter, but if the motor direction is the reverse of what is desired, switch two of the wires.


Do not operate the thruster for extended periods out of water. The bearings are lubricated by the water and vibration and noise will be greater when dry.

Clicking Noise

If you hear a clicking noise during operation, especially when operating in air, do not be alarmed. It’s normal.

The thruster uses solid plastic bushings and due to the tolerances of the bushings and motors shafts, the shaft can move slightly in the bearing. The noise is drastically reduced or eliminated when operated in water. The water acts as a lubricant for the bearings and smooths operation.

Care and Maintenance

Normal Care

During normal use:

  • Rinse with fresh water after use in saltwater to minimize the accumulation of salt deposits.
  • Rinse after operating in sandy environments to remove sand particles.

If operated for extended periods in the water:

  • Occasionally clean biological fouling and mineral deposits from the thruster or performance may be impacted.


You may need to take apart your thruster from time to time – or maybe you just want to take a peek at the inner workings of the T100! Either way, this tutorial illustrates how.

Thruster Disassembly/Re-Assembly
Learn how to take apart your thruster for cleaning, inspection or just to see how it works!


The motor does not start

This is usually an issue with the proper commands being sent to the ESC. Please see the ESC documentation for instructions on how to operate the ESC properly.

The motor does not start but the propeller tries to move.

This can be caused by a disconnected motor wire or a short between motor wires. Check that all three motor wires are connected and not shorting. To do this, check resistance of each phase pair in the thruster. Each thruster wire phases pair (blue/green, blue/white, green/white) should have the same resistance within 0.1-0.2ohms or so. If no connection is read or one pair has significantly higher resistance, your thruster has a fault. Please e-mail [email protected] if this fault is found.

The motor is jammed when turned by hand.

This can be caused by something jamming the propeller or by major internal damaged caused by overheating, short circuits, or heavily worn bearings. Please disassemble the thruster and inspect for damage or blockage.


For all the engineers out there, here’s some more info.

Comparison to T100

Test Results

  • Sand and Particulate Testing. The thrusters handle small particulate matter very well. See this video of testing the thrusters in heavy sand.
  • Depth Testing. Due to our unique fully flooded design where water moves throughout the thruster, pressure isn’t much of a concern. There are no air cavities to compress. The T100 should function well down to at least 500m.

Quality Control

We perform the following tests on every thruster before they are shipped.

  • Spin Test. The thruster is operated in air across the entire speed range to ensure that it operates correctly.
  • Visual Inspection. Each thruster is inspected for visual issues or damage.

Painting the Thruster

If you want the thruster to match the color scheme of your vehicle, you can paint the propeller and other components. We have tested Tamiya Spray Paint for Polycarbonate which comes in many colors and works well on the plastic.



Rusty is the founder and CEO of Blue Robotics. His background is in engineering but he likes to be involved in everything at Blue Robotics!


Adam started his journey in marine robotics as part of a high school MATE ROV team, eventually placing 1st at the International Competition!