Tides

[ayano3]

Just a bit of basic information on how the tides occur and how they are linked to the phases of the moon. Maybe of use to the new fowlers Tides

[harrycatcat1]

That is a very good link

 

Perhaps its me that's as thick as pudding but I still don't fully understand how it all works.

I am determined to get to grips with it though and have sent a link to work to print it off and study it.

 

Thanks

[DaveM]

Being a firm believer in the KISS principle (Keep it simple.. stupid) and also being diver of some 20 years, the basics are:

 

On a full moon & half moon you have a spring tide

On a quarter and three quarter moon you have a neap tide

 

A spring tide will produce the highest 'high tide' and lowest 'low tide'

A neap tide will produce the lowest 'high tide' and the highest 'low tide'

 

Spring Tide: This is because the Moon, Earth and Sun are in a straight line, thus producing the maximum amount of gravity and pull on the oceans.

 

Neap tide: The planetary bodies are in a right angled alignment so the gravitational forces are reduced and therefore the force of pull on the oceans is less, hence less water movement.

 

A marine chart will show you depth of water. This is known as 'chart datum' (the lowest recorded tide). So the hight of tide (depending on phase of the moon) will need to be added to chart datum to accurately calulate the depth of water for a given point in time.

[DaveM]

I should add that the green area on a marine chart is the 'drying hight'. Meaning.... if your still on it when the tide comes in you're in trouble..

[harrycatcat1]

Being a firm believer in the KISS principle (Keep it simple.. stupid) and also being diver of some 20 years, the basics are:

 

On a full moon & half moon you have a spring tide

On a quarter and three quarter moon you have a neap tide

 

A spring tide will produce the highest 'high tide' and lowest 'low tide'

A neap tide will produce the lowest 'high tide' and the highest 'low tide'

 

Spring Tide: This is because the Moon, Earth and Sun are in a straight line, thus producing the maximum amount of gravity and pull on the oceans.

 

Neap tide: The planetary bodies are in a right angled alignment so the gravitational forces are reduced and therefore the force of pull on the oceans is less, hence less water movement.

 

A marine chart will show you depth of water. This is known as 'chart datum' (the lowest recorded tide). So the hight of tide (depending on phase of the moon) will need to be added to chart datum to accurately calulate the depth of water for a given point in time.

 

 

Thanks

[UK fowler]

also make sure you read your tide hight from the same point of prodiction ie most people myself included that shoot sheps and south lincs use the boston dock sill as the datum of prodiction some sites on the internet use other points of prediction and they are not all the same a 6.9meter at dock sill is not the same as a 6.9meter tide at sutton bridge and you will get into trouble if you do not know the marsh well so always double check if not 100%

stay dry UK

[joknob]

on a full and new moon,not half moon for a spring tide. craig

[DaveM]

You say tomato etc etc, the calculations are what count and I've been doing this a long time.

[Reabrook]

I always believed that Springs occurred on the full and new moons. It would be interesting if you could expand on your half moon statement DaveM to see where we differ.

Edited May 31, 2012 by Reabrook

[joknob]

full moon and new moon,never been flooded off a marsh on a hlf moon even with a screaming nor,easterly. craig

[Grandalf]

on a full and new moon,not half moon for a spring tide. craig

 

[M ROBSON]

High water spring tide is about 8 o'clock on the Tay at Dundee every full and new moon. So you can work out roughly what the tides are going to be just by looking at a callander with the moons on, no need for a tide table, useful if your planning a trip the followling season,