Max Air Draught

[Barry]

Thinking about the type of boat I'd like has set me thinking about the width I want and looking at Jim Shead's map there is lots to explore on waterways where a beam of more than 6' 10'' is fine (accepting a max beam of 10' 6'' for the narrowest wide locks) This got me thinking of other limitations.

 

A lot of aft cockpit cruisers have fixed roofs over the cockpit and I wonder how limiting this is so my question is this: -

 

On the wider waterways what height are the lowest bridges? - In other words what is the maximum air draught I should look for on a boat if I am to take maximum advantage the broad waterway network?

 

 

 

 

edited for spacing

Edited October 15, 2010 by Bazza2

[alan_fincher]

Here's a starting point.....

 

BW Maximum Craft Dimensions

 

The 6' 9" limit on somewhere like the River Stort is real. If you have a fixed wheelhouse higher than that, you'd not get under the lowest rail bridges.

Edited October 15, 2010 by alan_fincher

[soldthehouse]

Here's a starting point.....

 

BW Maximum Craft Dimensions

 

The 6' 9" limit on somewhere like the River Stort is real. If you have a fixed wheelhouse higher than that, you'd not get under the lowest rail bridges.

I have often pondered this one, how do you "judge" this max air draught, meaning it obviously needs to take into account the width of boat and curvature of some arched bridges.

[Foxglove]

The National Trust Wey Navigation notes give Broadford Bridge , near Guildford , as having 6'4" clearance at normal water levels .

 

http://www.nationaltrust.org.uk/main/w-riverwey-info_boat_users.pdf

[alan_fincher]

I have often pondered this one, how do you "judge" this max air draught, meaning it obviously needs to take into account the width of boat and curvature of some arched bridges.

The above document makes absolutely no allowance for shape of boat or cabin, including "tumblehome".

 

"Headroom" just means if any part of your boat is heigher than that above the water, there will be structures it probably can't get under.

 

If it says max boat width is 7 feet, and max headroom is 6 foot 9 ins, (for example), it doesn't necessarily mean a boat that had it's highest point of the roof 6' 9" out of the water, but where the roof was still 7' wide, could necessarily pass through many of the bridges or tunnels. On most canals a "cuboid" of the maximum dimensions all over would fail to make it, and shape needs allowing for.

 

I'm not aware of a generic document that says "will my boat get through Froghall, Standedge, Harecastle or Gosty Hill, (as examples). It's a case of seeking local advice for each, usually.

[soldthehouse]

The above document makes absolutely no allowance for shape of boat or cabin, including "tumblehome".

 

"Headroom" just means if any part of your boat is heigher than that above the water, there will be structures it probably can't get under.

 

If it says max boat width is 7 feet, and max headroom is 6 foot 9 ins, (for example), it doesn't necessarily mean a boat that had it's highest point of the roof 6' 9" out of the water, but where the roof was still 7' wide, could necessarily pass through many of the bridges or tunnels. On most canals a "cuboid" of the maximum dimensions all over would fail to make it, and shape needs allowing for.

 

I'm not aware of a generic document that says "will my boat get through Froghall, Standedge, Harecastle or Gosty Hill, (as examples). It's a case of seeking local advice for each, usually.

I had always presumed that max meant max, leaving one to make adjustments for profile. This obviously creates many vagueries but is all we can hope for in reality. I suppose that one very quickly gets a feel for whether it will "go" or not

[Naughty Cal]

From memory the lowest bridges we have encountered so far which are within the cruising range of where you want to keep your boat have been on the Nottingham canal, just after you lock up off the Trent and the few bridges on the Ripon canal. All of which are 7'6" i believe.

 

I had always presumed that max meant max, leaving one to make adjustments for profile. This obviously creates many vagueries but is all we can hope for in reality. I suppose that one very quickly gets a feel for whether it will "go" or not

 

You would think so wouldnt you

[David Mack]

The above document makes absolutely no allowance for shape of boat or cabin, including "tumblehome".

Many, although by no means all, of the lowest bridges are flat structures, and so maximum headroom, without reference to cabin shape is a reasonable approach.

 

There are published profiles around for a few structures - Dudley and Standedge Tunnels come to mind, but as a wide boater you won't be going through either of those!

 

David