PoR Dynamics whilst in Reverse

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[LucAtC]

Hello TFM,
PoR in SSEx reaches 12 knots astern after 2 minutes if kept at full astern, and can easily be steered to keep its heading even at this speed.

At speeds more than 6 to 8 knots astern, steering is needed with very small rudder angles to stay on course, from 0.5° to 1.5°. The ship is then course unstable, it means that if you don't steer, she will begin to yaw.

Under 8 knots, the ship should steady her heading without help, and you can learn how to control the ship thanks to the yaw indicator and the rudder angle, as the ratio yaw rate/rudder angle to match the yaw is the basic data you must keep in mind, it depends mostly on the speed. But the course stability is (too) good under 8 knots.
No need to say, don't make a mistake when steering, if you go at a speed that your thrusters cannot control, otherwise you will throw the ship in a turn difficult to counteract.
When turning astern at speed, some caution is needed to keep the control of the ship. But that is not specific.
 
And I was perhaps not enough clear : Don't use the thrusters if you try steering astern, they are not at all reliable now, wait for the patch that will correct the controls. Try to use exclusively the wheel steering as it is now, both rudders together, until you can control the ship at any (reasonable) speed inside Dover or Calais. I think that leaving Beneluxhaven without thrusters is possible, but very difficult.

Regards,
Luc

[The Ferry Man]

Thanks for the info Luc, most appreciated, but I am still getting dodgy stern movements - reversing with engine set at -23% giving a speed of 4.3 knots astern, had the rudder at 0.9', and she was turning fine with a RoT of 2/3' per minute. I have reset the rudder back to 0, and her RoT has gone up to 17' per minute and rising?

Edit: now 24' per minute

[Aad The Pirate]

Thanks for the info Luc, most appreciated, but I am still getting dodgy stern movements - reversing with engine set at -23% giving a speed of 4.3 knots astern, had the rudder at 0.9', and she was turning fine with a RoT of 2/3' per minute. I have reset the rudder back to 0, and her RoT has gone up to 17' per minute and rising?

Edit: now 24' per minute

Ahoy Ferry Man,
Untill the patches are released it seems that the only way to come out of that strange behaviour is to use the engines to steer. If she swings to port to fast, stop port engine and slowly give throttle in forward direction till she's steady with zero angle per minute.
That would be, for the moment the only solution I will use.
Maybe you can try it out too?!
Kind Regards
Aad

[The Ferry Man]

Ahoy Ferry Man,
Untill the patches are released it seems that the only way to come out of that strange behaviour is to use the engines to steer. If she swings to port to fast, stop port engine and slowly give throttle in forward direction till she's steady with zero angle per minute.
That would be, for the moment the only solution I will use.
Maybe you can try it out too?!
Kind Regards
Aad

Thanks Aad, that could be a useful solution 

[seafrance]

hello ferry man,
pride of calais and pride of dover use a bow rudder when they manoeuvring astern out of calais, like the spirit class (pride of free enterprise, herald of free enterprise and spirit of free enterprise). when they are out of the port, they use the bow rudder to the left, they reduce their speed and they go forward with the principal stern rudder to the right. so they are very stable when they go astern. they don't use their thruster. so it is impossible to reproduce excactly the same with the pride of rotterdam because she hasn't a bow rudder like p&o ferries built after (european pathway (pride of canterbury), european highway (pride of kent), european seaway and european causeway (pride of burgundy)). in the eighties the port of calais was very small and they can't manoeuvring inside when they were berth 5 and after berth 6, but during these years, the port has been extended, so for the following built ferries they didnt need to have a bow rudder because the could manoeuvring inside the port.
sorry for my very poor english
regards

[The Ferry Man]

Hi Seafrance, your English is very good

Thanks for the explanation 

I know the Spirit class also had a Bow prop, but this was not added for the PoD/C


As you say, Calais Port now is large enough that the manoeuvrability of a bow prop is not needed, so the more fuel efficient Bow Bulb is used

[Heikodewal]

Tested the PoR and the Ferryman is complete right, she is unmanouverable in reverse.

[Alex Brown]

If she's reversing and starts to take the stern to port, give it a kick ahead on the stbd engine to null that turning effect - I wouldn't expect the thrusters to be of much use above 4knots anyhow really.
When operating small commercial vessels with twin screw in real life, I generally find that they hold course upto about 5knots and then if they start to steer off course, that is unrecoverable without either a reduction in power on one engine or a kick ahead on one or both of the engines to bring it back into alignment.

-Alex

[Aad The Pirate]

If she's reversing and starts to take the stern to port, give it a kick ahead on the stbd engine to null that turning effect - I wouldn't expect the thrusters to be of much use above 4knots anyhow really.
When operating small commercial vessels with twin screw in real life, I generally find that they hold course upto about 5knots and then if they start to steer off course, that is unrecoverable without either a reduction in power on one engine or a kick ahead on one or both of the engines to bring it back into alignment.

-Alex

As I stated before:
http://80.95.161.114/shipsim/forum/index.php?topic=20788.msg281467#msg281467

[Alex Brown]

As I stated before:
http://80.95.161.114/shipsim/forum/index.php?topic=20788.msg281467#msg281467

Yeah, my point being that it happens in reality - not sure about a large ferry, but if smaller vessels are anything to go by, this particular dynamic isn't a fault that should be fixed by a patch!!

-Alex