Ship Simulator
English forum => Ship Simulator Extremes => General discussions => Topic started by: Apejens on April 11, 2011, 19:35:03
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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 :2thumbs:
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I have a problem assigning joystick controls to the rudders, all other ships are configurable the normal way.
Greetings Uli
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The Coromuel in Virtual Sailor.. ;)
http://www.youtube.com/watch?v=MDeQG7Ezg7E
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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.
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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..
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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 :-X
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Which is rate of turn of Albatross when turning with only propellers (left ahead, right astern) ?
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Hello Andrej,
You asked details about the ferry dynamics.
The yaw rate with propellers only is around 18°/min, no rudder.
Full 35° rudder, one engine pushing ahead, one engine pulling astern, the yaw rate varies around 50 - 55°/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, 120°/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
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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...
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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 10°/min for a maximum of 13, and at 100 RPM, the ferry yaw rate after 15 seconds is 15°/min vs a maximum 17°/min. 150 RPM gives a maximum 25°/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.
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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?
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And after Luc finishes working that out, he will go on to work out quantum theory of mechanics before lunch!
:lol:
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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 didn´t just came up with this.
cheers
Ingo
....As I am no technician...what is a CP propeller?
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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.
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Hi frosen,
thanks for your answer, now I know what you mean.
brgds
Ingo
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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...
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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?
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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 20°, one shaft ahead and the other astern, the ship did readily pivot without speed ahead or astern, up to some 50°/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
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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.
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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! :D ), 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.
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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!!!
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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? ;)
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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 :)
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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.
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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.
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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 20°, one shaft ahead and the other astern, the ship did readily pivot without speed ahead or astern, up to some 50°/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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Hello Yaw,
The trial that you describe is to create a clockwise torque while countering it with 20° left rudder. Doing this trial resulted in a 8 to 10° port swing on my pc. Pc's are indeed sometimes weird. Even so, I don't fully understand how you came to the conclusion about the ferry reaction.
Also, the propeller efficiency astern is lower than ahead, and the ferry will slowly make way ahead with the shaft settings that you described. By the way, the slip ratio of the propellers is also taken into account for the thrust and consequently the rudder forces for all propeller powered ships.
Regards,
Luc
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Hello Apejens,
I don't fully understand the conditions where your manoeuver didn't work, there is indeed an important rudder lift due to the propeller flow, as the rudders are behind the propellers. Pivoting with no speed ahead is due to the rudder lift, prop walk and shaft eccentricity, what else could it be?
Certainly berthing was bow first, against or at a very short distance to the linkspan that you set both sides 75% ahead, full right rudder. Although I can only guess what you meant by not losing the bow, did the ship refuse to turn and to come alongside the quay? Could it not be an underwater obstacle that prevented it or did you try it also in an open place with no luck? I cannot anyway reproduce it, perhaps a description of the place where it happened could help clear the issue.
Regards,
Luc
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Hi Luc,
By "losing" the bow I mean that it would move sideways.
When docking a ferry, I'll generally dock her gently into the linkspan, then apply plenty of propeller thrust and a moderate rudder angle to bring the stern alongside. This will keep the bow pushed into the linkspan with such high power that the bow keeps in place and doesn't move away from the linkspan.
If I'd use full rudder and a more moderate amount of propeller thrust to bring the stern alongside,
the bow would not be pushed so hard into the linkspan, and it will in most cases then swing out from the linkspan.
These examples are without use of mooring lines, of course.
I apologize for my appaling abilities to explain in English, but it's the best I can do.
About the "Albatros IV" 's dynamics, there may be something with my computer that's causing the weird behaviour,
but in general she doesn't respond to the rudder except when making speed ahead...this is where I feel the dynamics should be tweaked a bit.
As I said, I brought her bow gently into the linkspan at Cowes, then applied forward thrust and st'b rudder to bring her stern alongside. Nothing happened at all, her stern stood still, until I tried the stern thruster, which brought her stern alongside. I would say she has the dynamics of a twin-screwed ship with a single rudder placed in the ship's center line.
I have to say that I don't understand why she should have a stern thruster either, as she didn't have it in the first place. A powerful, twin screwed vessel would not be needing such things.
Please note, Luc, that I am absolutely in love with the "Albatros IV" - I think the Papenburg sisters are some of the most handsome ships ever bulid, and VStep has captured that beauty magnificently.
I do not wish to be a moaning, complaining fool about these things.
I also really like the PoR, which has great dynamics too - as I said, I think the "Albatros IV" should behave like a smaller sister.
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Hello Apejens,
What you meant by "losing the bow" is quite clear, and if I can easily imagine that there is enough fendering at the bow in reality, I don't know how the virtual linkspan is made, particularly its friction coefficient or reaction to collisions.
I made similar tests at this "Trinity Wharf" linkspan. Once in the linkspan, I had the same result that you describe while pushing both sides ahead, but having starboard set slightly astern was enough to liberate the bow so that the stern could be brought alongside.
It was as if there was an all or nothing process about the bow rubbing the linkspan. Under a certain value of the thrust there is no friction at all and the "bow is lost", above this threshold the bow becomes locked and prevents pivoting. I have no idea of the reason, nor what to do about this place. Still, it is possible to get along, and the next patch will include less propeller turning astern action on the corresponding rudder.
There are various ways to show the rudder-propeller action at zero speed, be it simply by turning on the spot without use of the thrusters.
Still easier, there is a quay downstream at one ship length, where I made a similar trial, pushing against this solid wall and changing the rudder angle from one side to the other. The ferry pivoted, following faithfully the rudder thrust, with the bow sliding accordingly at a reasonably very slow speed. Certainly something that a single rudder between two propellers wouldn't allow.
Regards,
Luc
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@Apejens:
By "losing" the bow I mean that it would move sideways.
When docking a ferry, I'll generally dock her gently into the linkspan, then apply plenty of propeller thrust and a moderate rudder angle to bring the stern alongside. This will keep the bow pushed into the linkspan with such high power that the bow keeps in place and doesn't move away from the linkspan.
Can this cause damage like dents and holes to the bow?
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@Apejens:
Can this cause damage like dents and holes to the bow?
There's no damage model like in Ship Sim 2008
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I mean in the real world with locking the bow into the linkspan.
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I mean in the real world with locking the bow into the linkspan.
Oh yes, I've seen it happen :o :captain:
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I mean in the real world with locking the bow into the linkspan.
If it's done properly it shouldn't, the most likely time for damage to occur is when the bow actually contacts the linkspan, if this is done slowly then just pushing the bow into the linkspan shouldn't really do damge unless more too much force is applied, but obviously in real life it's hard to have the speed just right at the exacvt moment of impact and sea conditions also have an effect.
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A certain well known cruiseferry that used to run to Bilbao had a very experienced Cpt named "Robert Ross". I've never seen ANY ship approach a linkspan so accurately- especially not Bilbao- under any other Captain. I reckon that you could balance an egg between the linkspan and the stern and he wouldn't have broken it.
Other Captains on the other hand were a little more unsteady- either you would "feel" the bump or the ship would come to full stop and then edge backwards again (one time it took 4 times to line up (no wind- maybe bad tide?)
Sorry for the digression.
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I'm sure I'm beginning to get on Luc's/VStep's nerves here, but I haven't found myself reassured by any answers here. In order to prove this, I took the ferry for a spin at Bora Bora, docked with her port side alongside(which was, at best, difficult without stern thruster use), moored the ferry with a spring line, and put on full speed ahead and hard st'b rudder to bring her stern alongside.
Nothing happened, instead she swung her stern out from the quay with a speed of 1,2 knots.
To test the realisticness of her dynamics, I then applied hard port rudder without changing engine speed.
Surprisingly, this reduced her athwartship's speed to 1,0 knots. Is this realistic..?!
When this was done, she was docked stern against the quay.
On departure she was given hard port rudder, thereafter full speed ahead.
As the attached screenshot shows, at a SOG of 2,4 knots, she only has 0,3 knots speed athwartships.
As the SOG rises, her ROT increases and she eventually reach an athwartship speed of 4,8 knots at 8,1 knots forward.
This proves, in my view, that she is indeed configured to swing by her speed ahead, and not by the thrust made by her propellers. You may call it sailship-like dynamics, or, as I wrote further up this topic, that she behaves like a twin-screwed vessel with a single, centre-mounted rudder.
I do believe that a only a full revision of the ship's dynamics will do her justice.
Attached are some screenshots of my aforementioned points.
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Putting a forward spring ashore and going ahead on the engines is used to move the stern away from the quay when leaving the berth, it is not a way to bring the stern along side when approaching the berth, but even then only with dead slow ahead as full ahead on the engines will snap ropes in real life.
If you want to bring the stern in (when going port side to the quay) try using the starboard engine astern with full port rudder if the ship is stopped or moving astern and with no rudder if she is still moving ahead.
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You sure would piss off the guys on the forecastle ;D
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The ship moored ahead wouldn't be best pleased either :D
PING, CRUNCH/
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What kind of ropes have you been using then - made of paper, perhaps? :P
On almost every ship I've been on, we've always been fastening a spring line going from the forecastle and astern-wards when docking, then swinging the ship in by going forward i the spring line and applying rudder. I must add, these were coasters without a stern thruster, and only with a pretty dismal bow thruster. This method was even taught as "the way of doing it" in the "Ship Handling" study when I took my nautical education.
Please don't think I'd be using full power in real life - that would've annoyed the guys on the forecastle, surely, perhaps even beheading them ;D On the pictures above, I applied full power only to prove my point.
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I have also noticed these perculiarities with the handling characteristics of the Albatross. Her steering is definitely responding to speed over ground rather than thrust from the propellers. I even tried shoving her bow into a "solid wall" full ahead with both engines, but could not get any turning response from either a port full rudder nor a starboard full rudder. In my opinion, she handles just like a twin screw boat with a single rudder. In order for her rudders to to have an effect, you have got to be making way either ahead or astern.
For example, try backing her out of a berth at about 4-5 kts astern. When clear, come full ahead on both engines. Wait till the engines reach 200 rpms, then apply right full rudder. You will notice the bow start turning to the port up to about 12degrees/min. This rate of turn will eventually correct when the Albatross starts making headway. Vice versa with same trial applying left full rudder.
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What kind of ropes have you been using then - made of paper, perhaps? :P
We use a double polyrep spring with a total MBL of 54 tonnes as described by the OCIMF mooring guidelines :P
Ofcourse this is the way to get a single prop vessel off the quay - i'm really happy that it's possible in SSE! - but not full ahead as you say :D
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OK, pulling into the green field port of Portsmouth, coming in at about 7 knots
I put the port engine at 60rpm forward , and the starboard engine at 65rpm astern - this should start me turning, however I found that I just am currently slowing down only - no sign at all of any turning...
Will keep you posted...
Edit: 4.5 knots - still no rotation and approaching the berth area rapidly...
Edit 2: 4 knots, and currently slicing through Portsmouth, and no turning either
Edit 3: 3 knots, fast approaching the M275... still no signs of turning... :/
Edit 4: 2 knots now, passed the M275, have a RoT now! 1' per minute... :/
Edit 5: OK at about 1.2 knots it appears to have stopper decelerating at all :/
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This is why VSTEP should add under each boat the following:
Speed:
Tonnage:
Passagers load max:
Crew:
Fuel inboard capacity:
Fresh Water:
Supplies:
Engine Type:
Fuel Consumption:
Fuel Type:
Twin screw, triple screw?
Range(miles):
All there is, is the pointless information no one bother's to read I bet, then is the important information which is left out plus should have a medium sized photo of the ship in real life as you click on it. And if someone comments on this and say's oh sorry this is not ship sim pro excuse than that you are have no soul.
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Except for the propulsion, the rest of the info is kinda useless for manoeuvering :P
I'd rather see info like turning circle, left or right handed vessel, zig zag test and so on ;)
Edit: added a real wheelhouse poster.
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As it's a simulator you get to find out the info like that yourself and unlike in real life if you get it wrong you can go back and try again.
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If you want to carry out this particular move it can be done very well indeed in SS 20008. virtually all the ships there can be "sprung off" or, very carefully, sprung onto the quayside. The only comment I would make is for the Mate on the foc'sle head to be certain that he and all the men up there do NOT stand within the bight of the rope, but well clear of it. A Mate I knew was killed when a roller fairlead carried away and the bight of the rope snapped back and severed both his legs in an instant. He bled to death in a matter of a few minutes. Not funny at all.
What clanky says is worth its weight in gold. :thumbs:
Angus.
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Hello,
Clearly, having read captcj post that adds to Apejen's one, we don't use the same Albatross IV dynamic files. It is not impossible, but I cannot check that unless I receive a copy of the file itself to do a comparison. My mail address can be found in my profile, it is the file
C:\Program Files\Vstep\ShipSimExtremes\Projects\ShipSimExtremes\Data\Entities\Dynamics\Coromuel.act
TFM, do you have an idea of the yaw torque made by the propellers in your test conditions, ship speed 6 to 7 kts, and 60/65 RPM propellers having a pitch +/- 3 m, at 5.84 m distance from each other? I guess you don't. It is an impressive (or not) 14.5 tm, or a 0.3 t (3 kN) force exerted laterally at the stern. As you designed screw propellers, you can partly use a very interesting program, Javaprop, Design and Analysis of Propellers that can be used, changing the blade form and the air parameters into water, to get an idea.
Regards,
Luc
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TFM, do you have an idea of the yaw torque made by the propellers in your test conditions, ship speed 6 to 7 kts, and 60/65 RPM propellers having a pitch +/- 3 m, at 5.84 m distance from each other? I guess you don't. It is an impressive (or not) 14.5 tm, or a 0.3 t (3 kN) force exerted laterally at the stern. As you designed screw propellers, you can partly use a very interesting program, Javaprop, Design and Analysis of Propellers that can be used, changing the blade form and the air parameters into water, to get an idea.
Regards,
Luc
I see....
So this means it won't produce a turn? I would have thought a 3kN force on the stern would have priduced some Rotation, even if its not much...?
Thanks,
TFM
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You are right, pulling during 2 minutes could let the ship turn at 10°/min, disregarding hydrodynamic resistance, ie ship stopped. It wouldn't even break a 5 mm nylon rope. But once the ship is making way, the sway resistance and the yaw resisting torque increase strongly.
Anyway, the files that you have are certainly wrong, as the test made by captcj succeeds easily as it should do, in the 2 versions that I have. Do you still have a Steam version?
Regards,
Luc
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Using the propellors to turn seems like a cumbersome way..How about using the rudder..? ;)
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I was about to do a 180 turn to berth sternwards into the invisible berth 5 (Which also lacks a collision model) so I needed to turn and slow down, I do the same method with the White Marlin
And I no longer have a STEAM version of SSE
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Using the propellors to turn seems like a cumbersome way..How about using the rudder..? ;)
It's quite common to use propellor thrust in real life, so much so that on the museum which I am currently curator of if one engine is stopped with the ship making a headway of more than around 8 knots even the extra drag of the stopped propeller causes the ship to swing so much to one side that even full rudder can't counteract it, we have a feathering system which puts 90 degrees of pitch on the stopped propeller to reduce the drag and allow us to operate on one engine.
Rudders are only truly effective when the ship is making headway, there is an effect from the propeller wash, but it is minimal and is usually only really noticable when the ship is stopped in the water or when used to add to the effect of the ship moving ahead by increasing the engine thrust.
Going astern the rudders will work, but with reduced efficiency, and in the case of flapped rudders like the becker rudder using the rudders with too high a speed astern will damage the rudder.
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what happened to the bow ramp???? i see the controlls are on the ramp pannel on the Albatross 4, they are the bow and stern controlls, but theres a switch under them saying "open/Close" whats that for??? ive clicked it but it doesnt do anything??? is it for the missing Bow ramp??? ive seen someone with a pic useing the ramp in Dover
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They broke the ramp :doh:
I think its something to do with it not moving right,
It should be in the next
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I wish to thank Luc, who helped me download the right settings for the ship, which greatly improved the realism :)
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Is it possible that you could poste those settings, then? Maybe we are others who need the correct dynamic settings...
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Hi
On the Albatross IV, I have the stern thruster on and it produced a stern sideways thrust of 2.5 knots
I then put bow thruster on to stop the turning and make it start going sideways...
However I have found that the Stern thruster starts losing power and drops to 1.2 knots, whilst the bow thruster goes to 2.1 knots? starts it spinning the other way...? seems a bit odd...
*Both thrusters were at maximum power
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That is odd...
???
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Hi
On the Albatross IV, I have the stern thruster on and it produced a stern sideways thrust of 2.5 knots
I then put bow thruster on to stop the turning and make it start going sideways...
However I have found that the Stern thruster starts losing power and drops to 1.2 knots, whilst the bow thruster goes to 2.1 knots? starts it spinning the other way...? seems a bit odd...
*Both thrusters were at maximum power
I assume that you mean the stern was moving at 2.5 knots?
When you only have a stern thruster working you are only moving one end of the ship and in effect spinning the ship around her centre of lateral resistance, when you use both together you are moving the entire ship bodily sideways so there is a greater overall resistance.
The spinning effect of the stern thrust is cancelled out (and in this case reversed) by the bow thrust and as that was what was giving you the lateral movement of the stern then the stern will slow down, but the centre of the ship (or the centre of lateral resistance) which should have been almost stationary will start to move.
Sorry I couldn't put it any simpler :(
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Ahh no problem
yeah that is what was happening
I always assumed that a bow thrust and stern thust together would make you go sideways, and assuming the two thrusters where the same not make you spin when both on equally...?
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The 2 thrusters are rarely the same, bow thrusters are normally bigger as you also have the propellers and rudders to assist aft.
If they were the same then for both thrusters to make the ship move sideways the centre of lateral resistance would have to be exactly half way along the length of the ship, if you look at your original design for CQ you can see that the centre of lateral resistance would be towards the stern which would give the bow thrust a bigger turning moment and make the ship swing in what ever direction the thrusters were operating.
You should be able to make a ship side slip, but you will have to balance the thrusters to give a zero rate of turn.
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Ahh OK :thumbs:
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Or an alternative to Clanky suggestion and fine engineering explanation, you could try sticking a large pole on the deck (I suggest a Pole name Vladamir) attaching a large piece of cloth to aforementioned pole and call it a sail.
With aforementioned sail, point ship in general direction required and hope for the best. In the event that your self loading cargo complains that they wanted Calais and not the Azores then you tell them that if they can't take a joke then they shouldn't have joined.