maneuvring with Schottel or Azimuth thrusters

[SeaBart]

Hi guys,

Posted this here as probably mostly only tugs will have twin azimuth thrusters nowadays. Please feel free to correct of I'm wrong.

I accepted a job as master of a multi-purpose DP2-vessel, 62 x 13 m, 4.7 m draught, deadweight off about 1550 mt.
Vessel is currently under construction and is equipped with twin azimuth on the stern and twin bowthrusters.

Now: I have never sailed on a vessel with only azimuth propulsion, I know the theory behind it and heard a lot of stories from old salties I sailed with.
I'm not afraid to start maneuvering with her (very slowly @ first ) but it would be nice to have a bit more knowledge and a few tricks of the trade.

Does anybody mind sharing some experience, some tricks?? Or can anybody point me towards either somekind of training manual, or maybe even an online simulator?

Not far from me is actually a simulator where they give Azimuth maneuvering courses but the company doesn't wanna spend the money on it. And they won't give out their training manuals.

Will be much appreciated, thanks a lot!

[richard8000milesaway]

you are a lucky SOB. I have been captain of a very similar vessel (with same configuration) and they are a real charm to manuever. I don't claim to be the world's best ship handler, but I do pretty damn well and have avoided a few tight spots once or twice because of it.
as far as I'm concerned the key to remember when using this sort of thruster is to VISUALIZE HOW THE DIRECTIONAL FORCES you are applying will effect your vessel, to wit: dead in open water, if you position the port thruster at 90 degrees off the CL it will turn that part of the vessel in that direction (directly to starboard, of course the bow will go to port unless you kick in a bow thruster). the combination of bow thrusters and azimuths mean you will be able to "turn on a dime and leave 5 1/2 cents change". after a week or so I was able to plant my 80 meter 3000 ton vessel in between massive container ships with 3 meters clearance on both the bow and the stern, you will too, trust me.
if you lose one of the main thrusters you will still have incredible manueverability, for the above reason.
when steaming in open water and not using autopilot, I find it easiest to make minor course changes with just one thruster: keep one going dead ahead and the other adjust as needed.
as far as emergency stopping goes, you should be able to stop in a vessel's length or close to. in this case take the power off the thrusters, then rotate them 180 THEN apply power.
I agree with corporate: you don't need any training other then what you'll get onboard; it is really quite simple as long as you always VISUALIZE THE DIRECTIONAL FORCES acting on the vessel at any moment in time.
have fun!

[Jeffrox]

Some links for your info.
http://openpdf.com/ebook/azipod-pdf.html

http://www.schottel.de/eng/index.php

[SeaBart]

Thanks for the info guys!

Richard: when mooring/unmooring did you have the thrusters biased outwards or inwards?

[richard8000milesaway]

"when mooring/unmooring did you have the thrusters biased outwards or inwards?"

scenario: vessel is manuevering to come alongside, 5 meters from and parallel to the jetty, starboard side to, no wind or current or traffic.
in this case I would probably use my outboard thruster to push my stern in SLOWLY, leaving my unused inboard thruster facing away from the dock for an emergency get away. I am a speed freak: I always manuever slowly so I don't get dinked. so, kicking that stern in a little and a little, easy easy, I'll use the bow thrusters to kick the bow in to keep her parallel to the jetty. slowly does it. easy cheesy.
my unused inboard thruster will be used to either kick me forward or astern a meter or so as we make the final mooring line adjustments. then all fast!
easy as pie and bob's your uncle!
years ago (1995?) when I was a new captain I lost a thruster alongside jetty while manuevering when I used the inboard thruster and it sucked in cables or chains from the jetty! bad scene. never again. ergo I always prefer my outboard thrusters.....

[SeaBart]

Roger, makes sense.....

Reason I asked was that I have heard both methods used but never the real reason why which one is better. You make a good case for keeping them thrusting outwards.
Thanks

[The Rover]

With outboard thrust I find you get to where you want faster. Inboard is slower.
Outboard coming alongside a dock the wash will affect you because it will bounce off the sheet piles are whatever & will be more of a challenge to dock, whereas inboard thrust will be easier as you are not having the trust bounce off any where.
When working with other tugs in close quarters using the inboard method is preferred because you will not be washing the other tugs, with your thrust.
Also, when you want to stop thats easy, oppose your drives & apply power. then rotate to back down with them. That works on tugs pretty good.Just my two cents.