HWMT ?

[Skyva_2]

HAT is higher than MHWS, so is a real 'minimum'. As is LAT lower than MLWS.

 

[ccscott49]

Then why dont they use HAT?

 

[ggt9]

It is, lest we forget, a sign probably planted by the electricity board and not a clearance height on a navigational chart. MHWS or HAT might have been more familiar and useful but perhaps they like to use HWMT in pylon planning as some kind of simple standard for how high water might be.

It is also reportedly on a river where predicted tide heights aren't always a good guide to water level; you may have all sorts of floods, surges and little men in overalls doing mysterious things with sluices, wiers and locks.

In which case, a warning that the wires are "about 14m above high tide" is probably enough to cover them and make anyone with a big mast at least think about what may be about to happen.

Indeed, given the way things are going in some parts of the country, you may soon see such signs changed to read:

"Every horizontal rung of pylon still visible is about 3m clearance under the lines"

or replaced with a little sign on top saying

"Caution: underwater cables" /forums/images/graemlins/smile.gif

 

[AHoy2]

[ QUOTE ]


Next question ,how many of us know our airdraught ? /forums/images/graemlins/blush.gif



[/ QUOTE ]

All those choosing to pass under Poole Bridge in order to avoid the pre-bridge-lift dodgem session /forums/images/graemlins/ooo.gif

BTW the bridge airdraught is still shown wrt MHWS AFAIK.

 

[Sailfree]

As my posts suggests I knew they had changed but not sure what way.

I am sure you are right and appologies to eveyone that my post was misleading .

Changing to HAT does make more sense but one again check whats the basis of the clearance on the chart you are using.

Anyone know the date from which it changed.

I see no one has volunteered any clearance for top of mast to HT cables on a damp day!!

 

[jeanne]

Is this St Pierre Pill?? If so, a friend fried his electrics there some years ago........ /forums/images/graemlins/blush.gif

 

[graham]

Hello Jeanne.Its the Rumney River in the picture. I think the wires at St Pierre have been removed .

 

[ggt9]

[ QUOTE ]
I see no one has volunteered any clearance for top of mast to HT cables on a damp day!!

[/ QUOTE ]

5 feet (!) according to this gripping account...