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I'm good thanks, finding life busy but good.

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I'd agree that by 1912 standards Titanic's rudder was large enough. In fact, the central propeller aperture was in front of the rudder, which would have increased its effectiveness at high speed IMHO.

(Out of interest, I know people have mentioned that stopping the turbine engine would have reduced the rudder's effectiveness. However, it takes time for the turbine-driven propeller to slow down completely, if it's been turning at over 165 revolutions per minute, and my own opinion is that this wasn't a significant factor in the collision.)

Best wishes,

Mark.

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so do you think that if murdoch has just left the engines instead of reversing them, the titanic might have missed the iceberg?

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I think the damage would have been less, if the Titanic didn't miss the iceberg all together. Now some calculations could be done here to give you the best answer.

Jessica

Where do you get that information Jessica?

i mean, it's cool as all you posted lol.. really

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I don't even believe Murdoch did order the engines reversed. Fourth Officer Boxhall is the only person who remembered that order, and testimony from the engine and boiler rooms is unanimous in indicating that he just ordered the engines 'stopped.' Boxhall's testimony is always given more weight because he was an officer, but everyone can make mistakes and he had just survived a horrific disaster -- as with everyone else on the ship.

Even if Murdoch had ordered the engines reversed, I don't believe that there would have been time to reverse them. I think the belief that 'Titanic would have missed the iceberg if Murdoch hadn't ordered the engines reversed' is a common myth, disproved by simple research.

In any case, we don't know how far the iceberg extended underwater -- even if we have a rough idea. We just can't say.

Best wishes,

Mark.

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It's just the affect that slowing the speed of the ship would had in the effectiveness of the rudder. Am I right in saying the ship has to direct/displace enough water in a direction to make the turn. If the water is moving past the rudder at a slower speed, it will not move as much water (because less water is moving over the rudder)? The water also needs to be "clean". A slower speed also means the wakes would begin to close around and role along the ship. If the ship is going slow enough, the rudder will stall altogether and be practically useless at that time. Actually at this moment I can't even recall that information (the speeds and what not). I actually shouldn't have made that statement (until I atleast done some simple calculations), as I do not know what speed the ship was at by the time she hit the iceberg. As Mark said, the biggest unknown is just how far the iceberg extended out. I'd like to think that the distance the iceberg travelled along the hull would have been shorter (maybe 3 compartments actually punctured) if full speed was maintained. I'll have to figure that out at a later time though.

Jessica

That is quite correct Jessica.
i can see you are very knowledgable in aerodynamics.
If you think of it like this.
An Aircraft can only turn when a aeileron is raised this diplaces air and literally forces the aircraft to turn.

This applies to ships. The problem the Titanic had and this has been proven is that the rudder was not in the so called pro wash of the outer propellers when at hard port/starboard. i will include a diagram.

Although the rudder was big enough for a ship in 1912. It did not have the relative travel to to fully pertrude the outer prop wash.
as the water driven by the propeller hits the rudder the ship pivots on it's lateral center of gravity. The more water displaced by the propellers the quicker a ship will turn.

Ultimatly i do think the Titanic was just to close for it to turn in time

The little circles on my diagram represent the propellers

The long thin rectangle at the rear the rudder.

The big red rectangle the hull.

This is a harsh diagram but it should work.

A) represents a normal size rudder. As you can see the shear size of the rudder covers the left/right propeller when turning. This is called the propwash. The same as aircraft.

B) represents the Titanic, the rudder although big enough for the ship does not pertrude fulll into the propwash. HEnse the ship cannot turn as quick.

I hope this makes sense. It is very hard to explain in writing.
Thanks all
Shaun.

Attached file:   props.jpg (0.00 KB)

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How was the minimum rudder size calculated? If it was in percentage of the ships length, the lengh of the ship could have even made it mathimatically too small. Now, follow me here. I'm not sure how much relevance this will have to ships, but it could make sense if you look at it in a certain way...
When you stop a car at 50 km/h, say it takes 50metres to stop.
When you stop at 60 km/h, it might take 60 metres to stop
When you stop at 100 km/h, it could take 450m to stop.

The faster you go, the stopping time doesn't just add to itself, it multiplies.
This could be applied to a ship's minimum rudder size requirement.
As the ship gets longer/heavier, the minimum rudder size probably won't just keep adding on, it will have to multiply in the same way.

This is able to be proven with some algebra, (as anything seems to be) but given I'm tied up with solving systems of conic equations in my algebra class, I'm not going to attempt it.

Can anyone prove this, and/or explain the rules on minimum rudder size?
(Sorry for the crude logic here...)

That makes perfect sense Shaun and actually answers the question I had in my head about the prop wash and the rudder placement/length!

first-matey, calculating the rudder size, and designing it, would depend on the ship's size/weight, and design.

Jessica

As Jessica said, You need the ships weight, size and various other pramameters to calculate the minimum rudder size.

Although not hard to do, i have various other reports i am writing at the minute and it is a ver time consuming process. as i'm sure Jessica will agree.