Air Draft - who cares?

[KenF]

I've wrtten to YM a few times suggesting that they include 'air draft' in the statistics for the boats tested, to be told that it can vary.
However a builder should be able to state the air draft of any boat he builds otherwise how do owners know which bridges are safe to pass under? or what the clearance is?
With the proliferation of bridges these days I think it just as important as draft - any thoughts?

 

[The Q]

Yep very important.

 

[Boathook]

Some boats can have a family, cruising or sports rig but they should be standard I would think. Other variable would be aerials, etc. so that would be down to the owner to decide ....

 

[dunedin]

Suspect more of an issue for Norway, where the OP seems to be based, than most of the UK.

Our builders figure was about 1m short when we actually measured it, all in.

 

[Wansworth]

Was on a coaster on the Dutch waterways and we came across a bridge we could not decide if we could fit so I lashed together bits of pipea d the long boat hook and we motored up to the bridge arch,my makeshift gauge showed we would be ok………and we were

 

[bitbaltic]

Cardiff Barrage once called me up to ask the air draft as I was exiting with a bunch of leisure fishing boats. They didn’t fancy raising the bascule bridge until I told them it was 46ft. Matters sometimes.

 

[srm]

Essential to know on the west coast of Norway, as well as a few places on the west coast of Scotland. Don't forget to add the height of the VHF or other hardware on top of the mast. I used a long tape measure to find mine on all the boats where it might be useful.

 

[johnalison]

A sister ship arrived at the adjacent berth a few years ago, looking very new having just been sailed back from Sweden. The only flaw was the VHF aerial which was bent back some 30 degrees. The story was that the owners had taken friends as crew for the trip home and the four of them we having such a good time that the owner at the helm failed to notice that he was steering through the wrong span of the Tjorn bridge. Just knowing one’s air craft isn’t, apparently, enough.

 

[veshengro]

Was on a coaster on the Dutch waterways and we came across a bridge we could not decide if we could fit so I lashed together bits of pipea d the long boat hook and we motored up to the bridge arch,my makeshift gauge showed we would be ok………and we were

I signed aboard a Coaster in Sussex once, just before the Shipping Office closed on a Winters evening. I was told she was bound for France. When we sailed later that night I heard someone say we were bound for Paris!!!
Oh! yeah! I thought it was the coasting men winding me up because I had been Deep Sea on all my ships up to that time.
Early next morning we were all on deck dropping the Mast, Wheelhouse, life Boat Davits and even the Engine Room Air Vents.

Squeezing under the bridges of Paris...knowing your air draft is important sometimes..


Found another old photo..tight squeeze. A French River Pilot took the wheel from the outskirts of Paris.

 

[oldgit]

 

[Stemar]

Just knowing one’s air craft isn’t, apparently, enough.

Indeed

 

[veshengro]

Everything thing from Full Stop to just a trim.

 

[Seaway Channel]

I think I would prefer to measure my own rather than rely on a specification sheet of unknown accuracy - specifications do change over time as do loads in the boat. Bit like checking the depth your sounder is set at…

 

[The Q]

Tying this thread and the Ludham bridge tread together.

 

[Lightwave395]

Some 20 years ago I had a J44 with an 'air draft' of some 20 metres. I was going into Shamrock Quay for a few days and became convinced that someone was lowering Woolston Bridge as I approached to the extent that I got winched up to the top of the rig to go under the bridge...
It seems as we passed under there were a few metres to spare after all !

 

[mjcoon]

Yep very important.
View attachment 154298

Eastwood Whelpton at Upton is the wonderfully-named company that my (Mediterranean) sailing mate has been chartering from for decades!

 

[flaming]

I've wrtten to YM a few times suggesting that they include 'air draft' in the statistics for the boats tested, to be told that it can vary.
However a builder should be able to state the air draft of any boat he builds otherwise how do owners know which bridges are safe to pass under? or what the clearance is?
With the proliferation of bridges these days I think it just as important as draft - any thoughts?

I'm struggling to think of all that many bridges where the difference between the air drafts of similarish sized boats could be crucial, certainly in UK waters. Can you give an example?

 

[westernman]

I'm struggling to think of all that many bridges where the difference between the air drafts of similarish sized boats could be crucial, certainly in UK waters. Can you give an example?

Chertsey bridge:-

 

[flaming]

Chertsey bridge:-
View attachment 154348

I was very much thinking in terms of yachts with masts. None of which are going under that....

I guess I'm struggling to think of a bridge that different 35 foot cruisers (for example) would or would not fit under... Most are either very comfortable or just not an option.

 

[westhinder]

I'm struggling to think of all that many bridges where the difference between the air drafts of similarish sized boats could be crucial, certainly in UK waters. Can you give an example?

In Dutch waters it is more than handy to know your air draft. I have been asked my air draft so they did not lift the bridge deck more than strictly necessary. Saves a couple of minutes for the waiting road traffic. There are locks with a fixed bridge that some boats, mine included, will only fit under at certain states of the tide.