Maximum size less than lock size - locations

[Athy]

2 hours ago, David Mack said:

 

A bridge or tunnel is the limiting factor on air draft on most canals!

yes, and hence relevant to Patrick's question.

[Mike Todd]

15 hours ago, Goliath said:

Froghall Tunnel. 
 

I though that that was just a height not beam limit?

[David Mack]

6 hours ago, Athy said:

A Severner belonging to a CWDF member, 71 feet long (the boat, not the member) got round Briggate bend in Whittlesey a few years ago. Marmont Priory and (I think) Ashline locks were formerly 49 feet long (which is why the longest Fox's hire boats used to be 48-footers) but, as noted above, have been extended. On EA waters there's still a 40-foot one at the end of the Little Ouse. But these are locks, so they don't count.

Fulbourne at 71ft 6ins has been round Whittlesey Bend a few times.

[Athy]

4 minutes ago, David Mack said:

Fulbourne at 71ft 6ins has been round Whittlesey Bend a few times.

Come to think of it, I think I have seen her go past our house.

[ditchcrawler]

Approaching Ellesmere Port on the Shroppie

[beerbeerbeerbeerbeer]

2 hours ago, Mike Todd said:

I though that that was just a height not beam limit?

Yes, I was just replying to help out someone trying to remember the name of the tunnel. 👍
 

 

[oboat]

On 26/08/2022 at 08:43, Ewan123 said:

 

Fair point 😅 I wonder whether there are any/many where something else is the limit on air draught?

Yes boat profile.
Thinking of Box Boats, (Not applicable in the following but for some reason a large number of new build Broad & Wide Beam Boats have vertical cabins, and then wonder why they tree surf.) the most obvious one not mentioned is Stanage Tunnel (going west to east at least) Froghall is 6'-8"headroom, not a problem for most boats, but roof needs to be no more than 5'-0" wide. This allows for a slight kink which affects boats over say 35ft.

Bunkers Hill (below) tunnel is circular. Should be a few others I can't think of right now?

Edited August 27, 2022 by oboat

[magpie patrick]

Thanks for all the answers - interesting reading. I have since discovered that the new Hawford Bridge on the Droitwich Barge Canal (A449 crossing) restricts length of widebeams according to CRT figures. 

There are some odd ones, I know the Bridgwater and Taunton Well and I can't think of a bridge that is more restrictive than the locks - that said it is totally unsuited to boats much wider than narrow boats so I'm not going to argue! 

On 27/08/2022 at 09:03, oboat said:

Yes boat profile.
Thinking of Box Boats, (Not applicable in the following but for some reason a large number of new build Broad & Wide Beam Boats have vertical cabins, and then wonder why they tree surf.) the most obvious one not mentioned is Stanage Tunnel (going west to east at least) Froghall is 6'-8"headroom, not a problem for most boats, but roof needs to be no more than 5'-0" wide. This allows for a slight kink which affects boats over say 35ft.

Bunkers Hill (below) tunnel is circular. Should be a few others I can't think of right now?

 

That's a bit tight!  Which navigation is that on? 

[Jen-in-Wellies]

6 minutes ago, magpie patrick said:

I have since discovered that the new Hawford Bridge on the Droitwich Barge Canal (A449 crossing) restricts length of widebeams according to CRT figures. 

There is also one of the railway bridges that has been rebuilt with a corrugated tin lining, where the towpath means wide beams can't get through to the basin in Droitwich as they were historically able to.

https://canalplan.org.uk/wiki/photolicence

 

11 minutes ago, magpie patrick said:

That's a bit tight!  Which navigation is that on? 

Witham Navigable Drains.

https://canalplan.org.uk/place/2t5h

 

[Athy]

14 minutes ago, magpie patrick said:

 

 

That's a bit tight!  Which navigation is that on? 

The Caldon, mentioned earlier in the thread. Luckily it's almost at the end of it.

[agg221]

On 27/08/2022 at 09:03, oboat said:

Yes boat profile.
Thinking of Box Boats, (Not applicable in the following but for some reason a large number of new build Broad & Wide Beam Boats have vertical cabins, and then wonder why they tree surf.) the most obvious one not mentioned is Stanage Tunnel (going west to east at least) Froghall is 6'-8"headroom, not a problem for most boats, but roof needs to be no more than 5'-0" wide. This allows for a slight kink which affects boats over say 35ft.

Bunkers Hill (below) tunnel is circular. Should be a few others I can't think of right now?

To a large extent the Dudley tunnel has the same issue. The absolute air draft is low, but it's the profile which presents the main challenge. You need either very steep tumblehome, a narrow roof or to be low enough in air draft to fit the corners of the cabin within the profile.

 

Alec

[magpie patrick]

50 minutes ago, Jen-in-Wellies said:

 

Witham Navigable Drains.

https://canalplan.org.uk/place/2t5h

 

 Thought it might be somewhere like that!

[Richard Fairhurst]

By definition, boat length/beam on any lock-free canal will be limited by the angle you can take through bridges, of course. So the 'Ampton Boats of roughly 85ft x 8ft 6in were the biggest practical length on the Wyrley & Essington and the Wolverhampton Level, even though both canals are lock-free. I guess there must be a similar de facto length restriction on the Bridgewater (and the Ashby, discounting the former Marston stop-lock and the isolated Moira Lock).

 

Similarly, there was the Mon & Brec's turn under the Heads of the Valleys road until that got opened up, but I suspect you know more about that than me @magpie patrick!

Edited September 1, 2022 by Richard Fairhurst