The unmanned tug and the unmanned ship

[Kukri]

We had some discussion on harbour tug operations as they affect us all, a few weeks ago.

This paper was written by a group of people who are very well thought of in the harbour towage and pilotage world, so I thought I would post a link to it.

The Road Towards Autonomous Ship Handling with Tugs

 

[Habebty]

Is there a reason azipods have not been adopted on cargo vessels as they seem suitable for large exploration rigs? I would have thought a self positioning ship would be the goal?

 

[Kukri]

Oh good - I can answer that!

Azipods are used on cruise ships, which often have to manoeuvre in tight spaces, because the hotel load is so large that you might as well go diesel electric anyway, particularly as most cruise ships get under way at night when the hotel load is reduced so you can divert power to the pods.

The biggest azipods I think are still those fitted to the Queen Mary 2.

For cargo ships the additional cost of diesel electric with the additional transmission losses make pods unattractive because the ships spend more time under way and less time manoeuvring in ports.

But for some types of ship, such as container ships, we can get the same result using bow and stern thrusters, Becker rudders, and bridge wing control of the main engine.

Here’s one I made earlier. In fact she was one of the first to use what is now a commonly used system, thirty years ago. She can turn on the spot and can go sideways.

You will notice the thruster symbols (Maltese cross in a circle) fore and aft.



Again there is a trick - she carries big generators for reefer containers and these are switched to powering the thrusters when berthing and unberthing.

Bulk carriers and tankers don’t bother, and pay for tugs, because their port calls are less frequent.