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BRIDGE HEIGHTS, LOW AND HIGH WATER

donnygeoff

By donnygeoff
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donnygeoff

donnygeoff

Posted
Posted

Hi all,

I have had a quick search, but can not find the info I am looking for..

I know all bridge heights on the maps are shown for high water (so the Yarmouth ones say 7ft)

What I would like to know, is there anywhere I can find the max/min clearance of the bridges.

For example clearance at high water 7ft/ low water 9ft.

I know this will not be and exact measurement, because it depends on other factors such as wind. pressure. springs/neaps etc. but it would be helpful.

Thanks in advance.

:Stinky

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donnygeoff

donnygeoff

Posted
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Thanks Jonny,

But that is what I have found

The clearance measurements for bridges given are at Average High Water during the summer. There will be greater clearance near Low Water, especially at Great Yarmouth and in the southern rivers. Barometric pressure, rainfall and wind conditions all affect river levels so great caution should always be exercised and the bridge gauge board carefully noted.

Only high water clearance, not low water.....

I need to know wether or not to lower the forum flag on the way through Yarmouth :liar

Don't say a word Martin... :Stinky

:Stinky

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Guest

Guest

Posted
Posted
Hi all,

I have had a quick search, but can not find the info I am looking for..

is there anywhere I can find the max/min clearance of the bridges.

I've never been able to find a published list of LW clearances, either on the web or even on paper, and I've kept any eye open for it for many years.

It's a much more risky figure to declare, since a lot could ride on it's accuracy, (even decisions on what boat to buy etc.).

The nearest I've ever found, is the tide "Average Summer Springs Range" figures that used to be published in Hamilton's, before it's demise. When applied to the HW clearances, they give a rough idea, and the only method I've ever found available.

Acle Bridge - 0.5m

Beccles - 0.6m

Burgh Castle - 1.2m

Brundall - 0.3m

Horning - 0.2m

Loddon - 0.76m

Norwich - 0.6m

Oulton Broad - 0.8m

Potter Heigham - 0.4m

Reedham - 0.9m

St Olaves - 0.9m

I don't know how accurate all of those measurements are, but seriously doubt the Potter one, I've never seen a tidal height variation of 400mm ( 16 " ) there, and unfortunately, Yarmouth wasn't even on the list.

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Guest

Guest

Posted
Posted

I was going to say that most of those figures seem to have been gleaned from Hamilton's as well, and that the Norwich and Brundall figures are definitely well out, showing just 0.3m for each.

Then I looked again at the figures from Hamilton's that I put on this thread, and they show 0.6m for Norwich (which is more like it), but only 0.3m for Brundall, which is impossible !!

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MY littleboat

MY littleboat

Posted
Posted

The best thing to do is to look at the tidal difference between any given day and add that to the mean clearance level published. It won't be exact but will give you a very good idea what bridges you need to get under.

However beware at low water springs there is no guarantee you won't be digging a trench under your hull or picking up a rogue shopping trolley. Especially around Yarmouth

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diesel falcon

diesel falcon

Posted
Posted

hi,

have used this method before and it works at Yarmouth,for height at low water,

get the comparative low water height at Gorslton.....from here(the little pointer) http://www.norfolk-broads.org/index.htm

Take this figure off the greatest clearance of the bridge....can,t find it but it,s 13ft 2(4metres)

so tommorow you will have.....4 metres minus 1.05m equals 3metres(don,t be anal!!) equals...9 feet 10 7â„64 inches

we have used this method to get high boats under @11ft ,on springs you normally get a bit more :wave

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donnygeoff

donnygeoff

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If not follow common sense and use springs

Hi Mr Admiral,

I'ts not for mooring that I was looking for the info, but passage under bridges.

With the info I have now I can make an educated guess as to wether or not to travel to places that I need to go under bridges for, just to find that I have arrived at the wrong time and have to wait or turn back.

As I am down when the Yarmouth passage is just after sunrise and just before sunset (hires can only travel between these times) I am working out how much later I can be so to make it under.

Wouldn't want to keep one of Clives boats for another few days while I wait for the right clearance. :liar

cheersbar

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goodall_m1

goodall_m1

Posted
Posted

Hi Mr Admiral,

I'ts not for mooring that I was looking for the info, but passage under bridges.

Geoff

I think John meant use Spring Tides not spring ropes...

That is great for the retired Admiral out on his boat most of the time, he can plan his trip around the tide times. :naughty::naughty:

Those of us going during the Easter holidays and trying to make the maximum use of Bank Holidays are a bit more restricted.

This Easter is a real horror, Neap Tides and low water very early (just after Sunrise) and late (just before Sunset) in the pre-Easter week. It will be Springs just after Easter though , like just after we go home....

Don't do what I did on Hurricane last year and forget to take the forum flag down at the end of the trip.

(I had to ring Alphacraft and get them to post it back to me!)

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  • 2 weeks later...
Matt

Matt

Posted
Posted

Bill,

As you spend soooo much time onboard you could moor up at each bridge and record the high and low clearances.

This could then be repeated for the four seasons and also for Springs and Neaps.

I am sure we would all be interested in your findings!

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Guest DAYTONA-BILL

Guest DAYTONA-BILL

Posted
Posted

This thread is all very interresting, but we`re going to be on Swallow, a fwd dv boat and staying south, so bridge height is not really going to be a bother. 5 1/2 weeks, i can`t wait :teddy::teddy::teddy: . . Just hope the weather`s going to be a damn sight better than it was last year.

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Guest

Guest

Posted
Posted

Hi Geoff

knew it was somewhere

this should be what your after

http://www.thegreenbook.org.uk/

follow these instructions

1. click link about

2. once the page has loaded on left hand side click 2nd link THE GREEN BOOK

3. once loaded in the list navigation of the broads 10th link down bridge dimensions & type click it

Jonny

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