Future Carrier (Including Costs)
Joined: Apr 2006
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From: Portsmouth
Have a look who operates the yard....
Joined: Dec 2003
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From: 12 miles out
Reading the Navy Lookout article concerning the coupling failure it all starts to make sense. I've seen a number of sea water cooled couplings fail, the usual cause has been a constriction within the cooling pipework usually as a result of internal corrosion of inadequately galvanised components. This leads to a reduced flow and ultimately an over heated bearing/coupling. In a worst case scenario this could lead to a scored shaft and the need to remove the shaft and dress out the damage. The last time I oversaw such a repair the shaft had to go overseas as no UK facility had the infrastructure or experience to carry out the work.
Joined: Apr 2005
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From: Temporarily missing from the Joe Louis Arena
Joined: Apr 2006
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From: Portsmouth
Joined: Jun 2009
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From: Baston
Joined: Apr 2008
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From: Somerset
N
Joined: Jun 2009
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From: East Sussex
Rear Admiral Steve Moorhouse delivers the latest update on HMS Prince of Wales
Perhaps those on here more qualified than me, could comment on whether this could have been caused by a failure to grease the shaft, or was more likely caused by striking a submerged object.
Just as well we had a spare available to send Stateside
https://twitter.com/i/status/1565747919810138113
Significant Damage to the shaft and propeller and superficial damage to the rudder.
Significant Damage to the shaft and propeller and superficial damage to the rudder.
Just as well we had a spare available to send Stateside
Joined: Sep 2003
Posts: 343
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From: UK
Rear Admiral Steve Moorhouse delivers the latest update on HMS Prince of Wales
Perhaps those on here more qualified than me, could comment on whether this could have been caused by a failure to grease the shaft, or was more likely caused by striking a submerged object.
Just as well we had a spare available to send Stateside
Perhaps those on here more qualified than me, could comment on whether this could have been caused by a failure to grease the shaft, or was more likely caused by striking a submerged object.
Just as well we had a spare available to send Stateside
Joined: Dec 2003
Posts: 407
Likes: 49
From: 12 miles out
Not sure about the carriers but the vessels I've worked on did not have temp sensors on the water cooled bearings. Some systems have inspection windows in the pipework with flapper wheels which should be visible and seen to be spinning in the coolant flow. Temp sensors or not engine room rounds require the watch officer, or team, to use hand held digital thermometers to take temp recordings of all water cooled bearings. Results would be analysed and trends observed.
I imagine as the vessel had only reached Nab Tower before dropping the pick the engineering team were conducting their first rounds after leaving port before declaring the ship good for steady away.
I may be wrong but that's what I've done at exactly that spot on many occasions.
I imagine as the vessel had only reached Nab Tower before dropping the pick the engineering team were conducting their first rounds after leaving port before declaring the ship good for steady away.
I may be wrong but that's what I've done at exactly that spot on many occasions.
Joined: May 2002
Aviation Qualifications: ATP+Mil
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From: Downeast
Coupling or Bearing failure?
Why would a "coupling" need to be water cooled?
Or do Couplings contain bearings for two parts that rotate at the same speed and connect two pieces of structure together.
Terminology issue here or a technical difference?
Why would a "coupling" need to be water cooled?
Or do Couplings contain bearings for two parts that rotate at the same speed and connect two pieces of structure together.
Terminology issue here or a technical difference?
Joined: Apr 2006
Posts: 807
Likes: 425
From: Portsmouth
Definitively external coupling failure, NOT bearing. No cooling required, because it's not a bearing surface.
Oil injection couplings basically use hydraulic pressure to drive an outer (female) shaft over and up a tapered shaft of lesser diameter. When the desired position is achieved, pressure is released and you've basically got an interference fit with very high friction and hence torque Tx ability. It's a very similar system to how propellers are installed on their shafts. The coupling is contained in a fairing to prevent water ingress.
It's pretty simple - which is why it's so surprising that it appears to have failed.
Oil injection couplings basically use hydraulic pressure to drive an outer (female) shaft over and up a tapered shaft of lesser diameter. When the desired position is achieved, pressure is released and you've basically got an interference fit with very high friction and hence torque Tx ability. It's a very similar system to how propellers are installed on their shafts. The coupling is contained in a fairing to prevent water ingress.
It's pretty simple - which is why it's so surprising that it appears to have failed.
Joined: Apr 2005
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From: Temporarily missing from the Joe Louis Arena
Perhaps, until the Royal Navy get their act together, they could park HMS QE2 in the middle of the Indian Ocean and redraw all their maps, with everywhere 500 miles closer, to give the impression of being able to provide adequate coverage?
Joined: May 2002
Aviation Qualifications: ATP+Mil
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From: Downeast
NAB,
That explanation helps explain the usage of the words "Cast Iron Failure" when big things break bringing things to a stop.
So with that explanation and the report the Ship's Rudder was damaged in the process....can one assume the female section of the shaft backed off the male section ahead of it and the attached Prop made contact with the Rudder damaging it?
Just yesterday I had a small demonstration of Rudder/Prop failure on my 20 foot outboard when it managed to pickup a length of Ski Tow Rope with attached handle....wrapping the rope about the prop until the handle conveniently grabbed the Skeg of the outboard motor....bringing them to an instant halt.
Thank goodness for a trolling motor that got me to the shoreline where a wet dock repair was done.
That explanation helps explain the usage of the words "Cast Iron Failure" when big things break bringing things to a stop.
So with that explanation and the report the Ship's Rudder was damaged in the process....can one assume the female section of the shaft backed off the male section ahead of it and the attached Prop made contact with the Rudder damaging it?
Just yesterday I had a small demonstration of Rudder/Prop failure on my 20 foot outboard when it managed to pickup a length of Ski Tow Rope with attached handle....wrapping the rope about the prop until the handle conveniently grabbed the Skeg of the outboard motor....bringing them to an instant halt.
Thank goodness for a trolling motor that got me to the shoreline where a wet dock repair was done.
Joined: Mar 2009
Posts: 273
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From: 75' from the runway edge and 150' from the threshold
Dry Dock
Is a DD 1824' long x 305' wide of any use at all? I'm sure Harlands would be amenable and the crew could have a run ashore in Belfast. (Disclaimer, as a second year electrical apprentice I helped build it, but I suspect any of my work has been repaired by now)
A342
A342
Joined: Apr 2008
Posts: 216
Likes: 54
From: Somerset
NAB,
Thanks, I understand what is being talked about now.
Given that there is reportedly damage to the stbd prop, and rudder, which I understand is offset to allow the shaft to be drawn if needed, it seems that a potential mechanism is that the fairing failed, and departed the coupling heading for the prop, which chewed-up the fairing and itself then fired some or all the remains into the rudder. The coupling itself may, or may not, be OK.
N
Thanks, I understand what is being talked about now.
Given that there is reportedly damage to the stbd prop, and rudder, which I understand is offset to allow the shaft to be drawn if needed, it seems that a potential mechanism is that the fairing failed, and departed the coupling heading for the prop, which chewed-up the fairing and itself then fired some or all the remains into the rudder. The coupling itself may, or may not, be OK.
N