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Quick Connect Magnetic Coupling for Subsea and Ship Moorings

Energy efficient moorings using permanent magnets

Page last modified

Tuesday, February 2, 2021 - 14:33

Tow-botic Systems BV is developing underwater magnets for offshore use. Each specially designed permanent magnet is placed inside a watertight casing of ~200mm diameter. The magnet has a holding capacity of 0.5 ton over a large airgap which allows the operator to manage hull fouling or plate curvature easily. Fenders take the initial impact when connecting, prevent paint damage, and minimize sliding. The permanent magnet is electrically “switched on/off” with a 24Vdc power supply operating a hydraulic or electric actuator, but no energy is used when connected.

A single operator can quickly operate the magnetic coupling with a button. The magnetic coupling has multiple applications:

Subsea operators can attach their underwater vehicles to any steel object.
Pushboats can directly attach to the barge enabling better manoeuvrability.
Barges can attach to the ship's side.
Ships can be moored to the berth.
The 3dof platform arrangement allows roll, pitch, heave, yaw as well as surge, whereas, the gimbal arrangement allows for pitch and yaw. Passive or active compensation is possible. The system can be easily integrated into autonomous operations.
The magnet improves the efficiency of offshore operations by reducing the time taken to connect and disconnect.

Pro/con

Provides the ability to quickly connect or disconnect to any steel structure, saving time and cost of operations

Capable of operating in underwater and harsh environments

Large holding capability with a small diameter magnet

Electrically actuated, so can be operated using the available battery pack onboard

Extremely low energy required for the permanent magnet, only necessary when connecting or disconnecting

A large airgap allows the operator to attach to plates with hull fouling or buckling

No paint damage as fenders provided to take the initial impact when connecting

Gimbal allows for change of trim and relative motion of the vessels

Ease of conversion to autonomous operations with this magnetic coupling

Pushboats with high engine power require multiple magnets, which should be considered only if multiple connect-disconnect operations are expected

Specification

Areas of Application Smaller pushboats | Boats that have to be quickly moored/unmoored|Smaller pushboats, mooring at berth, attach to any steel structure offshore

Automation In the future the system can be easily integrated into autonomous operations.

Flexibility Offshore use, in harsh marine environments, easy to install.

Material Each magnetic coupler has a pull off of 0.5T each, using a small specially designed permanent magnet.

Power The coupler does not require any energy when connected, only a very small amount of energy during connect and disconnect by an electric actuator.

Sizes Diameter 170mm to work accross a large air gap of 12 mm.