FB 6 ........ sidethrusters ?

Ask yourselves what has changed since the old ferry was withdrawn. The Answer is the breakwater at the entrance which has resulted in far greater rates of flow through the narrows as high water is held up for far longer tan it was before. Would the old FB5 have coped with the faster flow rates and consequent faster rate of tidal height drop. Were the designers made aware of of the change in current flow rates or were they told to use the existing conditions. If they were not told to allow for faster rates of flow then no wonder they have washed their hands of the project.

David MH
 
davidmh said:
Ask yourselves what has changed since the old ferry was withdrawn. The Answer is the breakwater at the entrance which has resulted in far greater rates of flow through the narrows as high water is held up for far longer tan it was before. Would the old FB5 have coped with the faster flow rates and consequent faster rate of tidal height drop. Were the designers made aware of of the change in current flow rates or were they told to use the existing conditions. If they were not told to allow for faster rates of flow then no wonder they have washed their hands of the project.

David MH
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The new breakwater was completed in the autumn of 2015 but FB 5 continued in service until Jan 3, 2017.
FB 5 presumably coped with the faster flow rates and consequent faster rate of tidal height drop throughout 2016
 
I too think the new breakwater is a bit of a red herring / scapegoat.

When I first saw FB6 I thought ' Jesus ! Someone has tried to get the Queen Mary into the berth for a Leisure 17 '.

One only needs look at the relative weight and windage.
 
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davidmh said:
Ask yourselves what has changed since the old ferry was withdrawn. The Answer is the breakwater at the entrance which has resulted in far greater rates of flow through the narrows as high water is held up for far longer tan it was before. Would the old FB5 have coped with the faster flow rates and consequent faster rate of tidal height drop. Were the designers made aware of of the change in current flow rates or were they told to use the existing conditions. If they were not told to allow for faster rates of flow then no wonder they have washed their hands of the project.

David MH
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Missing the bigger factor that the new ferry is much larger. Its longer and greater displacement, so it shows a greater cross section to the tide flow.

I haven't seen the before an after breakwater bathymetry reports, but knowing the river as I do, I suspect there's little change at that point.
 
Why don’t they consult with people who operate ferries successfully - and why does it need to be a cable ferry anyway.

CalMac have run a few ferries in challenging locations. And the tidal flows are a LOT less than those in Kyle Rhea where a small independent ferry to Skye has been running for decades, with tides regularly 8 knots or so (and no cables needed)
 
burgundyben said:
Missing the bigger factor that the new ferry is much larger. Its longer and greater displacement, so it shows a greater cross section to the tide flow.

I haven't seen the before an after breakwater bathymetry reports, but knowing the river as I do, I suspect there's little change at that point.
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It seems then that it was mistake using the old chains. They should have been increased in size so that the increase in weight counteracted the increased cross section of the vessel.

There is a very close similarity with "red lines using green ink" where red lines represent the increased size of the vessel and the green ink represents the old chains.

It is written into the specification that FB 6 should use the same chains as FB 5 but at some point the "Expert" should have said if you increase the size of the vessel from green to red you must also similarly increase the size of the chains. I guess he was up against the same sort of thing as the "expert" in the video.
 
dunedin said:
Why don’t they consult with people who operate ferries successfully - and why does it need to be a cable ferry anyway.

CalMac have run a few ferries in challenging locations. And the tidal flows are a LOT less than those in Kyle Rhea where a small independent ferry to Skye has been running for decades, with tides regularly 8 knots or so (and no cables needed)
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You can certainly see the similarity with the Medina although it is about 4 times the distance across. Just need to scale their little boat up to carry 20 cars plus 140 foot passengers and the problems will be solved.

https://en.wikipedia.org/wiki/Kylerhea#/media/File:Scotland_Glenelg_Kylerhea_ferry.jpg
 
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VicS said:
It seems then that it was mistake using the old chains. They should have been increased in size so that the increase in weight counteracted the increased cross section of the vessel.

There is a very close similarity with "red lines using green ink" where red lines represent the increased size of the vessel and the green ink represents the old chains.

It is written into the specification that FB 6 should use the same chains as FB 5 but at some point the "Expert" should have said if you increase the size of the vessel from green to red you must also similarly increase the size of the chains. I guess he was up against the same sort of thing as the "expert" in the video.
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Local comment was that it was not due to local council but central gov spending limits. Maybe the expert did raise this and has no liability ? Who decided to proceed though ? It certainly seems very noisy on board now. If the design of the ticket machine is any indicator of the thinking it's hardly surprising that it's still having problems. Is it due to be taken out of service for proper repairs any time soon?
 
ashtead said:
Local comment was that it was not due to local council but central gov spending limits. Maybe the expert did raise this and has no liability ? Who decided to proceed though ? It certainly seems very noisy on board now. If the design of the ticket machine is any indicator of the thinking it's hardly surprising that it's still having problems. Is it due to be taken out of service for proper repairs any time soon?
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See
https://www.islandecho.co.uk/floating-bridge-improvements-to-be-designed-by-wight-shipyard/
http://www.iwcp.co.uk/news/16362950...sions-improvements-for-cowes-floating-bridge/
 
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ashtead said:
Thanks for link . Hopefully this will see a solution to present issues but at £1.50 a trip it's rather lost its attraction anyway sadly .
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£1.50 is a return ticket though isnt it ?

I beleive locals and regular users can buy a "savercard which reduces the fare to £1.
 
dunedin said:
Why don’t they consult with people who operate ferries successfully - and why does it need to be a cable ferry anyway.

CalMac have run a few ferries in challenging locations. And the tidal flows are a LOT less than those in Kyle Rhea where a small independent ferry to Skye has been running for decades, with tides regularly 8 knots or so (and no cables needed)
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Don't ask awkward questions ! Anyway I'm a councilor, have to keep this short as I'm off to get my new Ferrari.
 
I now see the council are addressing the much more serious issue of the headgear worn by Eric the friendly ticket collector and of course ignoring the chain noise complaints of local residents
 
dunedin said:
Why don’t they consult with people who operate ferries successfully - and why does it need to be a cable ferry anyway.

CalMac have run a few ferries in challenging locations. And the tidal flows are a LOT less than those in Kyle Rhea where a small independent ferry to Skye has been running for decades, with tides regularly 8 knots or so (and no cables needed)
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The Strangford Narrows one is bigger than the Kylerhea one and copes with the big tides and currents there by being an appropriate design, having suitable propulsion equipment & hefty engines.
 
AngusMcDoon said:
The Strangford Narrows one is bigger than the Kylerhea one and copes with the big tides and currents there by being an appropriate design, having suitable propulsion equipment & hefty engines.
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Yep another good example of why it is not tricky to do a ferry for such a tidal location, just need to look elsewhere for successful approaches.
 
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