Underwater & Marine
Linear Actuators

Aerospace Linear Actuators
Underwater Linear Actuators
Underwater & Marine
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Uncrewed Vehicles
Industrial Linear Actuators
Science & Research Linear Actuators
Science & Research
Medical Linear Actuators
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Other Industries

For 30 years Ultra Motion has been a leading supplier of pressure-compensated oil-filled linear actuators for the most critical subsea applications. Our unique design allows for reliable actuation to depths greater than 6,000 meters below sea with self-compensation and an extremely small footprint. We offer the most cost effective PBOF solutions in the industry where power density, size, and reliability are critical.

The AU Servo Cylinder is Ultra Motion’s next-generation submersible actuator that includes built-in BLDC control electronics and contactless absolute position feedback. For applications requiring full ocean depth operation, we have a 6000+ meter version with CAN 2.0B, RS-422 serial, and RC PWM operating modes. We also offer the unmatched marine environment reliability benefits of a pressure-compensated oil-filled actuator at an economical price point with our “shallow” AU, ideal for uncrewed surface vessels, hydrofoils, and shallow operation to 75 meters.

Our submersible products are commonly used to operate hydroplanes on subsea vehicles, deploy instruments/accessories like float releases or sensors, raise masts/antennas on USVs, control hydrofoils or rudders on USVs, actuate subsea valves, and more.

Design and Manufacturing Capabilities include:

  • MIL-A-8625 Type III (Hardcoat) anodized aluminum enclosures
  • 316L stainless steel hardware and shafts
  • Cathodic protection
  • Wet-Mate Underwater Connectors (Seacon, SubConn, Teledyne, etc.)
  • Pressure compensated oil filled designs
  • Stepper and Brushless DC motor options

Performance Specifications including:

  • NEMA 17 models (forces up to 100 lbs)
  • NEMA 23 models (forces up to 500 lbs)
  • Depth ratings up to 20,000 ft
  • Temperature ranges from -30°C to 65°C

Industry Spotlight

Rov Tether Latch Release

Ultra Motion’s pressure balanced oil-filled aluminum actuators offer high performance linear motion at depths up to 20,000 feet below seawater. The power density of this subsea actuator is extremely high due to enhanced thermal dissipation in the motor coils caused by fluid motion. The motion of the actuator’s rotor induces a motion in the inert oil surrounding the motor, leading to an increase in the effective thermal mass of the motor and a decrease in thermal resistance between windings and case. When operating underwater, these actuators are exposed to a near infinite thermal reservoir and a much higher convective heat transfer coefficient than air. Ultra Motion’s encased underwater actuator’s thermal design allows the actuator to be overdriven to 2 – 3 times the standard power rating, allowing for high power density underwater linear actuation.

Rov Tether Latch Release

  • 115 lbf continuous @ 8 in/s , 250 lbf peak (in air)
  • Nema 17 BLDC motor
  • Oil filled cabling
  • Pressure balanced oil-filled compatible connectors (PBOF)
  • Electrical conductivity throughout the entire actuator and sacrificial zinc anodes for corrosion resistance.
  • Type 316 Stainless steel and type III hard coat anodized aluminum components