Jim Currie
Member
Yes he did, every twin screw ship has that capability but it is not an emergency action. Such an action takes time and he did not have time to do that. Normally it is used as an assist to the rudder when turning in narrow, confined areas... not in open ocean.
Hope that helps.
Stephen Carey
Member
Ha ha, no, not quite. I think I included a dit somewhere on this site copied from my Quora answers. It's quite a long job, then as now. Let me know if you want a copy.
Steven Christian
Member
Maybe they didn't know how to double clutch...
Mike Spooner
Member
I shall be sailing on the SS Shieldhall ship with triple expansions steam engines this coming week end from Southampton. I certainly be asking the questions on how to reversing the engines and time scale to so.
If any body else has a question to ask please let me know.
If any body else has a question to ask please let me know.
Steven Christian
Member
Sounds like a cool trip. I'm envious. No questions offhand but a 30 sec video clip would be cool if they let you do it. Cheers.
Mike Spooner
Member
I will be trying for a video run indeed.
Sec'
Member
Running propellers in opposite directions to help swing the ship is only really effective while maneuvering with the ship barely moving, and takes a looong time. At full service speed the water would just stall/cavitate around he reversed prop.
The strain on the framing, blades, and shafting would make it very very risky.
I believe that they rang down 'Stop' prior to collision to avoid the fear utmost in their minds, having a turning prop striking the berg.
The strain on the framing, blades, and shafting would make it very very risky.
I believe that they rang down 'Stop' prior to collision to avoid the fear utmost in their minds, having a turning prop striking the berg.
Jim Currie
Member
At last! A bit of common sense.
Your "belief" is spot on.
No experienced bridge officer would touch the engines if the intention was to steer the ship out of danger. However, the second the starboard bow hit any underwater obstruction - let alone ice - the first thought would be for the propellers.
During a hard LH turn, on a twin-screw ship, you would stop both props. Because if you simply stopped the starboard one, the thrust of the port one would negate any LH turning motion, and, as you say, the rudder would be useless due to turbulence and cavitation.
Unfortunately, when Murdoch stopped both props, the turbulence caused by them and the dragging center prop. would have rendered the rudder useless in a very short period of time.
By the way, having actually maneuvered ships driven by triple expansion engines, I can confirm that an emergency request for full astern was normally a two-part action-- STOP...then Full astern and always with a double ring. (telegraphs were chain-driven in the "olden days".
If I remember correctly, the reason for this was that four sets of rings in a noisy engine room would be heard as prolonged alarm-sounding bells which would be sure to be heard and immediately recognised as an emergency. Then, of course, there was also the changeover procedure from ahead to astern which took time and effort.
Tim Aldrich
Member
I agree with that statement Mr. Currie. I think any sane person, in charge of any sort of watercraft, even the jet ski squids, could agree that a loss of propulsion is, probably, the worst scenario outside of being afire.
Sec'
Member
And to add to that Olympic losing a blade on her maiden voyage would really make it fresh in their minds
Mike Spooner
Member
A Sinking ship must rate pretty high to!
Mike Spooner
Member
I was on the SS Sheildhall last Sunday down in the engine room and asked about the reversing. It takes about two second flat at 75rpm. OK the engines are considerably smaller than Titanic had. The steering gear as to Titanic design was quick to with two steam motors doing the work
I took a video of the working engines. The noise, heat with escaping steam in places was great stuff. But my video needs a bit of editing sort out before I show it.
I took a video of the working engines. The noise, heat with escaping steam in places was great stuff. But my video needs a bit of editing sort out before I show it.
Jim Currie
Member
I presume you mean engaging the astern gear when you say "about 2 seconds, Mike? Ringing the telegraph takes about 2 seconds.
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