Calculating Yarmouth Bridge Clearance

[Simon]

im trying to better understand the bridge clearances Gt Yarmouth at low water, as my airdraft is 11`3"

published high water clearance listed as 6`9" based on average high water, 

does anyone know what this average HW height is, im trying to work out if say its (5`3") 1.62m then a zero HW height would give me 12`

am i on the right lines with this?

 

[CambridgeCabby]

If you ring Yarmouth Yacht Station when you are considering coming through then they will be able to give you an accurate clearance 

[dnks34]

You will probably want to make sure your planned passage doesnt fall during springs, if we have any strong westerly winds that will also affect the maximum clearance on any given day.

Someone will probably give you a better explanation before long but if they dont as CC said the Yacht Station will help you. 

[JohnK]

You will probably want to make sure your planned passage doesnt fall during springs, if we have any strong westerly winds that will also affect the maximum clearance on any given day.
Someone will probably give you a better explanation before long but if they dont as CC said the Yacht Station will help you. 

Won’t spring tides give the most clearance at low tide?
I thought springs meant the highest highs and the lowest lows.

[dnks34]

When its springs and we have high winds thats when I thought we had higher highs and higher lows

 

[Simon]

16 minutes ago, JohnK said:

 

Won’t spring tides give the most clearance at low tide?
I thought springs meant the highest highs and the lowest lows.

 

yes, low water springs will be the lowest

[Simon]

1 hour ago, CambridgeCabby said:

If you ring Yarmouth Yacht Station when you are considering coming through then they will be able to give you an accurate clearance 

good tip, i didnt know they would commit to forcasting a possible clearance

[dnks34]

2 minutes ago, Simon said:

good tip, i didnt know they would commit to forcasting a possible clearance

Might depend how far ahead you are planning! 

 

[Smoggy]

Spring tides will give best clearance at LW as well as least clearance at HW, average HW means sod all and should never really be used and isn't on proper charts, they use LAT which is lowest astronomical tide as chart datum, the weather can make it lower than this but only on exceptional circumstances.

A northerly or easterly wind will generally give higher levels as it pushes the tidal bump around the coast quicker, low pressure also lifts the water, a southerly wind can hold the tide back and give lower than predicted tides.

Also factor in BA shows fixed bridges at yarmouth the same as haven bridge the same where ordanance survey show haven as higher at MHWS so they do not all sing from the same sheet, I trust OS more than BA, BA never even got close to helping us win a major world war.

BA tide tables do not use chart datum as zero as normal rational people do so be aware of the differences.

I'm not about to give any actual figures to any of the above as I've been in the pub too long and not going to be liable to your roof damage.....

P.S. I hope even a small percentage of this makes sense, even good spelling will be a bonus to me!

 

[ranworthbreeze]

2 hours ago, Simon said:

im trying to better understand the bridge clearances Gt Yarmouth at low water, as my airdraft is 11`3"

published high water clearance listed as 6`9" based on average high water, 

does anyone know what this average HW height is, im trying to work out if say its (5`3") 1.62m then a zero HW height would give me 12`

am i on the right lines with this?

 

Hello Simon,

On Ranworth Breeze with the canopy and masthead down we have an airdraft of 9 ft 8 inches so basically we look for a clearence of 10 ft  at all Bridges. 

I use the Broads authority tide tables because it gives me an height at low water. We look for a height of  0.14 or lower, with your height you will need to look for a minus level tide to pass through Yarmouth.

We have a simple guide when coming down river for checking for 10 foot at the bridges on the ladders approaching the yacht station, if you can see 7 rungs of the ladders out of the water, you have 10 foot at the bridges, we use this as a guide because the bridge height indicators are few in number and the lower markings are all worn away.

Regards

Alan 

[Smoggy]

It's even easier if you are heading up the bure, check the calendar and if the schools are out turn back it's not worth it, half the pubs put the prices up for summer and you won't get a mooring.

[Simon]

1 hour ago, Smoggy said:

Spring tides will give best clearance at LW as well as least clearance at HW, average HW means sod all and should never really be used and isn't on proper charts, they use LAT which is lowest astronomical tide as chart datum, the weather can make it lower than this but only on exceptional circumstances.

A northerly or easterly wind will generally give higher levels as it pushes the tidal bump around the coast quicker, low pressure also lifts the water, a southerly wind can hold the tide back and give lower than predicted tides.

Also factor in BA shows fixed bridges at yarmouth the same as haven bridge the same where ordanance survey show haven as higher at MHWS so they do not all sing from the same sheet, I trust OS more than BA, BA never even got close to helping us win a major world war.

BA tide tables do not use chart datum as zero as normal rational people do so be aware of the differences.

I'm not about to give any actual figures to any of the above as I've been in the pub too long and not going to be liable to your roof damage.....

P.S. I hope even a small percentage of this makes sense, even good spelling will be a bonus to me!

 

there does seem to be inconsistencies between sources,

reeds almanac lists river bure yarmouth bridges as having 2.3m  at MHWS.

1 hour ago, ranworthbreeze said:

Hello Simon,

On Ranworth Breeze with the canopy and masthead down we have an airdraft of 9 ft 8 inches so basically we look for a clearence of 10 ft  at all Bridges. 

I use the Broads authority tide tables because it gives me an height at low water. We look for a height of  0.14 or lower, with your height you will need to look for a minus level tide to pass through Yarmouth.

We have a simple guide when coming down river for checking for 10 foot at the bridges on the ladders approaching the yacht station, if you can see 7 rungs of the ladders out of the water, you have 10 foot at the bridges, we use this as a guide because the bridge height indicators are few in number and the lower markings are all worn away.

Regards

Alan 

thanks Alan,

this gives me hope, i realise i will only have a few days around a spring tide to north

[vanessan]

2 hours ago, ranworthbreeze said:

 

I use the Broads authority tide tables because it gives me an height at low water. 

I will second that. The tide tables are very useful in that respect providing more of an idea of what heights can be expected at both low and high water. 

[ranworthbreeze]

Hello Simon,

Looking at the Broads Authority tide tables the 16, 17 and 18th April low water tides (early morning) are quite low, allowing for the hour difference for Yarmouth the 16th is around 5.00 am and later on the next two days.

Regards

Alan

[Simon]

27 minutes ago, ranworthbreeze said:

Hello Simon,

Looking at the Broads Authority tide tables the 16, 17 and 18th April low water tides (early morning) are quite low, allowing for the hour difference for Yarmouth the 16th is around 5.00 am and later on the next two days.

Regards

Alan

Hi Alan, 

yes these look nice and low. Will always need to be a spring tide for us.

im thinking of going round in the car for a reckey to view the gauges at different  low water times and build up a better picture of clearances and find my safe low water tide height.

the idea being able to plan well in advance northern trips.

thanks

Simon

[MauriceMynah]

That's a good idea Simon. Reality often seems to differ from the written word, especially when tide tables are concerned. There's little that can compare with actual experience. It might be worth your while to have a long chat with the BA Rangers there too