The Haven Bridge

[VetChugger]

There is an easier example of these "pawls" up here in Gods Own Country all along our canals at the lock gates used for paddle lifting and lowering.

[Londonlad1985]

I've always called that sort of thing a ratchet 

[grendel]

the ratchet is the sharp pointy gear the pawl engages with

[FairTmiddlin]

2 hours ago, Vaughan said:

So we are saying that Haven Bridge is a twin bascule bridge, like Tower Bridge, which is balanced by counter weight and the lifting is effected by the transfer of weight, usually in hydraulic tanks?

In which case I agree with FairTmiddlin. What have pawls got to do with it?

Constructed in late 1920's (opened in 1930) of Victorian architecture. Built on two 100 feet cassions 28 feet wide piled into the river bed using compressed air.

Exactly A Twin Bascule that is Counterweighted with 250 tons of Scottish Granite per side

and if it looks familiar it's because it was manufactured by Sir William Arrol and Co Ltd who also built the Forth Rail Bridge in 1890, Tower Bridge in 1894 and the Nile Bridge at Cairo in 1908

And as far as I know the original pumps and motors still power her.

[FairTmiddlin]

2 minutes ago, MorningSwan said:

Just a thought, while Peel Ports are responsible for the operation of Haven Bridge who actually owns it and responsible for its maintenance, PP, GYBC or Highways England?

Yes we all know it’s old and unreliable, maybe even listed, I haven’t checked but whoever it is actually responsible should maybe spend some on it to bring it up to a reliable modern standard to facilitate the right of navigation of the river without the aggravation and undue interference like has recently taken place.

That is of course assuming there actually was a problem with it in the first instance.

 

Still owned and maintained by Norfolk Highways

Matbe they will modernise it when they get the third crossing, as they said they would in the late 1950's, when the third crossing was supposed to be built.

[Vaughan]

"Hitler - had only got one pawl

Doenitz - had two but very small

Himmler - had something simmler

but poor old Goeppawls

had no pawls - at all.

[LondonRascal]

Quote

engineers speak engineerese,

Great line that

[grendel]

1 hour ago, FairTmiddlin said:

Constructed in late 1920's (opened in 1930) of Victorian architecture. Built on two 100 feet cassions 28 feet wide piled into the river bed using compressed air.

Exactly A Twin Bascule that is Counterweighted with 250 tons of Scottish Granite per side

and if it looks familiar it's because it was manufactured by Sir William Arrol and Co Ltd who also built the Forth Rail Bridge in 1890, Tower Bridge in 1894 and the Nile Bridge at Cairo in 1908

And as far as I know the original pumps and motors still power her.

Tower Bridge does have locking Pawls though - see this snippet of a report from a company that upgraded the systems:-

Quote

Modern traffic weight loads and volumes over the bridge were adversely affecting the main bearings on which the deck structures pivot. The dead weight of the bascules and the live load of the traffic were not being carried fully on the resting blocks and locking pawls, but also on the shaft bearings.
Because of misalignment and wear, the pawls didn’t properly lock the ends of the bridge decks in the down position and they didn’t correctly engage.

As a result some bearings were taking on more load than others. Left unresolved, the bearings and pivot mechanisms would suffer further damage, leading to a major bridge shutdown for repairs. In addition uneven loading causes misalignment of the two bridge decks.

I suggest this may be the problem they are now experiencing at Haven Bridge.

[BrundallNavy]

If you want to know how this type of bridge works there is a feature on ITV news Norfolk (on now)

[BroadAmbition]

I have forwarded the link for this thread onto the Peel Ports Manager at GYA - Whether or not he will read this thread - I knowest not.  Even if he does, I doubt he will comment on it directly - but may drop a line to me.  We will see

Griff

[JohnK]

I have forwarded the link for this thread onto the Peel Ports Manager at GYA - Whether or not he will read this thread - I knowest not.  Even if he does, I doubt he will comment on it directly - but may drop a line to me.  We will see
Griff

Now that could be very interesting considering what some people above have been saying about him and his team
Does anyone have the phone number for the Have I Got News For You lawyers?


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[Guest]

9 minutes ago, JohnK said:

 

Now that could be very interesting considering what some people above have been saying about him and his team
Does anyone have the phone number for the Have I Got News For You lawyers?


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Exactly , personally I think that was a bad idea , if he reads it and he probably won't but should he do so he's not going to be pleased at trial by forum , without a doubt he won't respond here IMHO ( often wrong ) as that would entail joining to do so and why would he bother , remember a lot of those commenting wouldn't need the bridge raising or wouldn't ever ( shouldn't ever,) be going that route so technically it wouldn't matter to them , where as it does matter to a lot of others some of whom are not member's here so don't necessarily know anything about this .

To me and its time to let it go now , an apology has been received and its highly unlikely anything else will be forth coming , I know several people dont believe the reasons stated by the operators but TBH that's speculation as proving otherwise would be virtually impossible .

Its worth bearing in mind many others enter an exit via this route without a problem but on this occasion there was a problem .and hence I'd tend to believe the operators since its as stated impossible to prove otherwise ( with the exception of taking them to court over the failure,)

Time to move forward I think .

[grendel]

I for one would love to know how the locking pawls work, are they a mechanical contrivance dating from the construction of the bridge, or newer hydraulic pins driven in to make the bridge safe

[grendel]

That said, having read about the trouble the ones on Tower Bridge were giving it doesnt surprise me that they are the weak point in the system, it only takes a fraction out of alignment, and they wont do their job properly (or lock in place) plus the suitability of the heavy traffic that might be using the bridge

[Smoggy]

As I previously said they had locking issues (in the up position) last summer when I went through as had to be waved though as the lights wouldn't change to green without the locks in place so the explanation wouldn't surprise me at all.

One time last year swmbo called to book a lift and left a message for them to call back, her battery went flat and they called my phone when they couldn't get through, they had bothered to look at recent bookings for the boatname to see if there were other numbers rather than ignoring the call so I have no issues with them.