Drying Height ????

[Nosealegsyet]

Just started the 4th module of my day skipper theory, which needs charts, the first question is about drying height, i dont understand wikipedia's meaning of this word

On a nautical chart, the drying height is the vertical distance of the seabed that is exposed by the tide, above the sea water level at the lowest astronomical tide. On admiralty charts a drying height is distinguished from a depth by being underlined. This article about geography terminology is a stub.

Can someone please explain to me in laymans terms what the above means thankyou

 

[bluejasper2]

hi nosealegsyet, drying height is the amount of seabed that is uncovered by the tide at the tides lowest point(at low tide the exposed seabed may be three feet above the height of the water)so on the chart the amount of sea bed exposed is put above the line, normaly drying areas are shaded green also.

 

[James L]

Just started the 4th module of my day skipper theory, which needs charts, the first question is about drying height, i dont understand wikipedia's meaning of this word

On a nautical chart, the drying height is the vertical distance of the seabed that is exposed by the tide, above the sea water level at the lowest astronomical tide. On admiralty charts a drying height is distinguished from a depth by being underlined. This article about geography terminology is a stub.

Can someone please explain to me in laymans terms what the above means thankyou

The numbers on the chart all based on the lowest of low tides, if there's a line under the number it's how high the land will be above water level, if there's no line it's how low the land is below water level.

 

[Rocksteadee]

To add to that;
Big number with line under, think negative depth, if that helps
And small number next to it is decimal

 

[guernseyman]

The language perhaps relates more to sandy or muddy areas

Down here in the Bay of St Malo the drying heights refer more often to rocks, which you are trying to avoid at all costs.

 

[Nosealegsyet]

got it guys, thanks everyone

 

[Mr Googler]

Lowest astronomical tide is a datum point used by all tide predictions and chart makers etc....

So....the chart say 3ft 3 underscore (or 1m) is the drying height for a particular bit of land.

Tides for the day in that area are
Low Water 12.00 0.5m
High Water 18.00 3m

If you go down there at 12.00 0.5m of water will be there so 0.5m of land will be above the water.

If you go there at 18.00, 3m of water will be there so the land will now be seabed with 2m of water depth between the seabed and the water surface.

 

[oldgit]

Why would anyone be interested in drying heights.

When planning your trip, there are so many things to distract you while underway.
Keeping an eye out for other vessels, checking for obsticals in the water, monitoring the instruments (especially Ts & Ps), listening to the engine note, enough fuel to complete journey,where exactly is your cup of tea plus worrying about mooring at your destination.
Pre planning trip at home or during quiet half hour aboard is a good plan and will lighten the load.
You can get nav software to do this job, but a chart and ruler also does the job.
Here on the East Coast going directly between bouys/waypoints ought be the best option.
Problem is you might have lots of water under you at the start and finish but a sandbank in your path halfway across, fine if you can see it, not so good if it is just underwater.
Many skippers will take advantage of a falling tide to speed them on their journey.
A line drawn on your chart will identify any possible problems regards lack of depth around low water and you can alter your track accordingly.

There is nothing more worrying than watching your depth gauge announce you are fast running out of water and then having to make an instant decision about which way to go. .