Topic: Albatross IV handling (Read 24340 times)

Apejens · « **on:** April 11, 2011, 19:35:03 »

Dear VStep, I love your new ferry pack - the best thing you ever did.

I would like a few dynamic tweaks to the best-looking ferry class ever built - the Papenburg sister "Albatross IV".

- These ferries did not have a stern thruster.
- Nor did they have fixed-pitch propellers and direct reversible engines, instead there was CP propellers.
- The ferry seems a bit 'quick' on the bow thruster, it should be a bit more lower-powered.

Again, I wish to understate that I'm very pleased with the game and VStep's efforts to keep us whining gamers pleased

Ule · « **Reply #1 on:** April 12, 2011, 09:52:30 »

I have a problem assigning joystick controls to the rudders, all other ships are configurable the normal way.

Greetings Uli

saltydog · « **Reply #2 on:** April 13, 2011, 06:16:31 »

The Coromuel in Virtual Sailor..

http://www.youtube.com/watch?v=MDeQG7Ezg7E

Apejens · « **Reply #3 on:** April 13, 2011, 15:02:45 »

Also, I feel that the ferry should have different set of controls - like on the "Esperanza", where there is one lever for each of the engines. As I said, the stern thruster should be removed.
There seems to be an issue with the rate of turn when using the rudder and the engines astern/forward,
which is why you'll need the stern thruster the way the ship is configured today.
She should respond more to propeller/rudder handling, the way she is now, it seems the rudder only works when the ship's making way.

Any thoughts on this?

Oh, and by the way, WHAT beautiful ferries they were, the Papenburg sisters.
Such beauty will never again be seen at sea.

Captain Best · « **Reply #4 on:** April 13, 2011, 15:08:50 »

I love the Albatros IV, It's a very nice ship Indeed!

I'm agreed with you apejens.. (epic name btw)
I've had some problems with her too.. That suddenly one of the "joysticks" In Game just freezes..
So you can say the joystick broke down... Very sad when you've sailed a nice distance and then dock and experience problems..

Pride of Dover · « **Reply #5 on:** April 14, 2011, 12:56:05 »

Quote from: Captain Best on April 13, 2011, 15:08:50

I love the Albatros IV, It's a very nice ship Indeed!

I'm agreed with you apejens.. (epic name btw)
I've had some problems with her too.. That suddenly one of the "joysticks" In Game just freezes..
So you can say the joystick broke down... Very sad when you've sailed a nice distance and then dock and experience problems..

im gona have to agree with you there, shes a nice ship, i dont mind the stern thruster, but i too experiance the steering problems, i traveled from dover-calais with her in an hour and a half, and the she crashed and sunk at calais with the bouncy queysides

andrej · « **Reply #6 on:** April 16, 2011, 18:01:35 »

Which is rate of turn of Albatross when turning with only propellers (left ahead, right astern) ?

LucAtC · « **Reply #7 on:** April 16, 2011, 22:57:55 »

Hello Andrej,
You asked details about the ferry dynamics.
The yaw rate with propellers only is around 18Â°/min, no rudder.
Full 35Â° rudder, one engine pushing ahead, one engine pulling astern, the yaw rate varies around 50 - 55Â°/min, depending on the ahead thrust.
Sidestepping with the bow thruster at half RPM is possible at a speed of 1 kt, full rudder without fore and aft speed.
The smallest turning circle diameter full ahead is 194 m, 2 times the length at the waterline, 120Â°/min at 6.6 kts.
The maximum speed is 16.9 kts.
Rudder from stop to stop is 14 seconds.
Pure sway speed due to thrusters only is 1.6 kts
Regards,
Luc

The Ferry Man · « **Reply #8 on:** April 16, 2011, 23:10:44 »

I find the stern thruster on the Albatross IV is a bit of a handful...

It seems to only start working at over 50%, unlike the bow thruster...

LucAtC · « **Reply #9 on:** April 16, 2011, 23:50:59 »

Hello TFM,
Did you check it in detail at rest? If I set the stern thruster from rest at 75 RPM, after 30 sec the yaw rate is 10Â°/min for a maximum of 13, and at 100 RPM, the ferry yaw rate after 15 seconds is 15Â°/min vs a maximum 17Â°/min. 150 RPM gives a maximum 25Â°/min.
I guess you tested the thrusters while having some way, both thrusters and their controls are identical. The difference lies in the distances to the center of mass and to the center of lateral resistance : 43 m for the aft thruster, 40.45 m for the bow thruster. Their depth is also slightly different. The results are of course not the same, not only because of the various distances, but also due to the moving position of the pivot point and to the difference in water resistances ahead or astern, but I don't feel the same as you do.

Regards,
Luc

The distances are from the CoM, of course.

Apejens · « **Reply #10 on:** May 13, 2011, 19:53:08 »

Again, I tried the "Albatross IV", only to be annoyed by its lack of realistic handling.
I docked very gently at the linkspan at Cowes, bow-first, and then I applied hard st'b rudder and half speed ahead.
Normally, a ferry like this would then gently bring its stern alongside with the rest of the ship, but there was no rate of turn at all when I did this, which proves my point from further up in this tread:
The "Albatross IV" only responds to the rudder when doing speed ahead, in other words it doesn't respond to propeller thrust at all.

Dear Vstep: The prettiest ship in the game needs a bit of handling work done in order to work out in a realisticly satisfactory way. You're so close to making the most enjoyable ship perfect, why don't you finish it?
The ferry should behave like a smaller "Pride Of Rotterdam".

These changes would be:
- A ferry that responds more to propeller walk and rudder
- CP Propellers?
- When this is done, remove the stern thruster, as the Papenburg sisters didn't have this. An identic set-up like the original ships is crucial to a realistic game experience, in my view. After all, who would fly FlightSim with a propeller-driven 747?

Stuart2007 · « **Reply #11 on:** May 13, 2011, 21:33:08 »

And after Luc finishes working that out, he will go on to work out quantum theory of mechanics before lunch!

Sunseekeringo · « **Reply #12 on:** May 14, 2011, 13:03:34 »

Hi,

I love the Albatros as well and was really surprised that this old vessel has such a good behaviour and is equipped with a sternthruster.

But I am really disappointed to read now that this is not actually true? I assume that the vessels which are presented here are as accurate as possible? But how can be there a sternthruster if there is no one in real life? When these vessels were designed there must be a reason for that propulsions and I think they didnÂ´t just came up with this.

cheers
Ingo

....As I am no technician...what is a CP propeller?

frosen · « **Reply #13 on:** May 14, 2011, 13:28:39 »

Hi Ingo,

CP propellers has Controllable Pitch. The ship can adjust the speed, and go forward and reverse
by adjusting the pitch on the propellers, rather than change direction on the props.
Like propeller on an aeroplane with props.

Regards,
Frode.

Sunseekeringo · « **Reply #14 on:** May 14, 2011, 14:00:19 »

Hi frosen,

thanks for your answer, now I know what you mean.

brgds
Ingo

Jaw · « **Reply #15 on:** May 29, 2011, 09:55:29 »

I 100% agree with Apejens. Please make the vessels realistic!

I was so much looking forward to manouvering the Albatros IV, but was really disappointed. There was no stern thruster on these vessels so please remove it. In stead configure the dynamics so that putting the rudders in e.g. 20 degrees, ahead on one engine and astern on the other, will make the vessel turn with no ahead or astern motion - as would be done in the real world!

Just found out that the ship is reacting on the rudder position when going astern. When putting the rudder hard to port I got a rate of turn of more than 40 degr/min, which is totally unrealistic.

Thanks a lot...

Stuart2007 · « **Reply #16 on:** May 29, 2011, 15:21:41 »

One of the excuses for not allowing people to add their own ships into the game is that vstep is aiming for a much more realistic performance from each ship than could be achieved by us ourselves.

Aint working that way, is it?

LucAtC · « **Reply #17 on:** May 29, 2011, 22:15:08 »

Hello,
There was indeed way too much astern rudder-propeller interaction, it will be modified in a next patch if possible, I thank you for the remark. Also, if I can find exact references of the propellers, the FPP could of course be changed to CPP.
About the stern thruster, I think to have read that over time one or some of these sister ships did receive a stern thruster, but you still have anyway the possibility to disregard its use for a better or preferred game experience.

The two next points seem rather puzzling, as the rudders having been set indeed at 20Â°, one shaft ahead and the other astern, the ship did readily pivot without speed ahead or astern, up to some 50Â°/min, of course provided the engines rpm have been set correctly. Also, there is already definitely enough rudder-propeller interaction, and the ship does respond to her rudders, without speed and propellers ahead.
Is there any possibility that your system has some hardware or software issue?
Finally, what question is there about propeller walk? In the present configuration, the pitch arrangement of the FPP is standard, port side left handed and starboard side right handed.

Regards,
Luc

Third Mate · « **Reply #18 on:** May 30, 2011, 02:10:52 »

This got me thinking as well, some of the smaller / medium ships have the 747 flight sim comparison. Been on Red Jet but in Brisbane, and there is no way this one sprints so powerfully, you can feel the drag that's sorta the force is pulling you back.Not sure if i explained it well, but VSTEP was on the right track in SS08 you could start to have that feel each time you pushed the throttle forward. In SSE that pulling back feeling is gone completely for each small/medium vessel.

clanky · « **Reply #19 on:** May 30, 2011, 09:20:50 »

I'm not sure if I understand you TM, are you saying that the small medium ships respond too quickly when the power is applied?

In real life this effect is much more noticable on larger ships with greater mass, you can make a tankers propellor turn at 150RPM for instance, but all that will happen is that the propellor will cavitate and the ship will actually increase speed much more slowly than she would if the revs were increased gently (a principal which I have been trying to explain to captains for the last 20 years!

), whereas something like red jet will pick up speed much more quickly, this also varies with propulsion methods etc, water jet propulsion will give full thrust regardless of the ships speed and acceleration will be much quicker than with a propeller which will only give full power when the RPM / pitch is closely matched to the vessels speed, each ship has a propeller curve which shows the pitch / RPM compared to the ship's speed and power requirement.

Stuart2007 · « **Reply #20 on:** May 30, 2011, 10:13:37 »

I shall translate Clanky's comments for us mere land lubbers:

For straight to 150 RPM = getting in your car, banging the revs to redline, letting the clutch up suddenly, go buy new tyres.

For gradually increasing to 150 RPM = driving your car the way it was intended thus less damage to tyres, you actually get a grip on the road and you will actually increase your speed more quickly.

I have been trying to explain this to my drivers for the past 20 years!!!

Stuart2007 · « **Reply #21 on:** May 30, 2011, 10:15:24 »

Incidentally, all this talk of ships turning at 50 degrees/min... I have been in Dover many a time for the night and watched ferries turn to go aft onto the linkspan and I've never seen on take 3 minutes to do a 180 degree turn.

Am I missing something somewhere or is the lager in Douvres to strong for me?

Jaw · « **Reply #22 on:** May 30, 2011, 11:30:45 »

Hey LucAtC,

Appreciate you taking the time to listen and explain.

I just tried putting the rudder 20 degr to port and then the port engine on 60 rpms ahead and the stb engine on 60 rpms astern. This resulted in a turn of rate of 8 degr to starboard (!?) not to port. This indicates to me that the ship is reacting more on the astern thrust than the ahead. Or maybe this only happens on my system?

Regarding the sturn thruster I do not know if it was fitted on some of the vessels. Also I can live with it beeing there and just disregard it if the dynamics discussed here works

---

About the propellor walk it also depends on what you try to achieve. If you want to increase the speed of the ship then the RPMs must be increased slowly. However if you want to achieve a large turn rate in e.g. a turning basin then using the propellors for a kick ahead at e.g. half ahed with hard to port/stb rudder will achieve this.

TerryRussell (â€ 2012) · « **Reply #23 on:** May 30, 2011, 20:51:28 »

Hi Jaw.

"Propellor walk" is the "paddle wheel" effect whereby a propellor tends to force the rear of the ship sideways under the right circumstances. Vessels of many sizes use this effect to gently (usually) kick the stern into or away from the quayside, etc.

Apejens · « **Reply #24 on:** May 30, 2011, 21:52:18 »

Quote from: LucAtC on May 29, 2011, 22:15:08

Hello,
There was indeed way too much astern rudder-propeller interaction, it will be modified in a next patch if possible, I thank you for the remark. Also, if I can find exact references of the propellers, the FPP could of course be changed to CPP.
About the stern thruster, I think to have read that over time one or some of these sister ships did receive a stern thruster, but you still have anyway the possibility to disregard its use for a better or preferred game experience.

The two next points seem rather puzzling, as the rudders having been set indeed at 20Â°, one shaft ahead and the other astern, the ship did readily pivot without speed ahead or astern, up to some 50Â°/min, of course provided the engines rpm have been set correctly. Also, there is already definitely enough rudder-propeller interaction, and the ship does respond to her rudders, without speed and propellers ahead.
Is there any possibility that your system has some hardware or software issue?
Finally, what question is there about propeller walk? In the present configuration, the pitch arrangement of the FPP is standard, port side left handed and starboard side right handed.

Regards,
Luc

My point was that she didn't respond to rudder together with propeller use, as I used both engines forward together with hard st'b rudder. When you get a certain ROT with propeller/rudder use, it indicates that it's indeed the propellers forward/astern that makes the ferry turn.
In my experience with twin-screw ferries, you might want to run both engines forward when the ferry touches the linkspan, together with rudder use, to bring the vessel's stern alongside.
75-80% engine power forward and 20-30 degrees rudder will bring the ferry gently alongside without 'losing' the bow, if you're docking without use of mooring lines, as we usually don't use in Norway.
This is impossible with the "Albatross IV" in its current configuration.

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