Ramsey Island

Tides

The tides of the Ramsey Sound are among the strongest and fastest flowing in the world.

The St Davids peninsula juts out into the Irish Sea, which has a strong North-South tidal flow. Generally as we all know the flood tide ( flowing to the north) is the incoming tide and the ebb tide (flowing to the south) is the outgoing tide.

Sounds simple ....no.!!

Imagine being sat on the beach for a day. The tide is coming in so, as above the tide is flooding. It comes to high water. What happens at high water - the tide starts to go out (i.e. ebb)? No... . Well yes the tide does start to go out but the tide is infact still flooding i.e. still running to the north.

Confused - probably !!. Well to put it into a concise maritime context, the North flowing flood tide runs from three hours before high water to three hours after high water. The ebb tide runs for three hours after high water, through low water to three hours before high water. The little time between the change in direction is the true definition of slack water. It is all to do with the momentum of the tide, which is a huge force. It cannot stop dead on high or low water so its flow of direction " overflows ".

If you grasped that you are doing well but it becomes a little worse. Because St Davids Peninsula juts out into the Sea and Ramsey Island itself acts as a " pebble in a stream" the flow is further confused. The "pebble" forces water around it, which accelerates causing a vast water flow or flume.

As such the time of low water is dependant upon the size of tide (max height of high water - dependant on the phase of the moon, barometric pressure, wind direction and specific position on the coast.

After all that (if you survived) I guess you would like a general synopsis on the tides.

Take Milford Tide times and add an average 15mins plus for geographical distance
The ebb tides starts 2 1/2 hours before low water and runs to 2 1/2 hours after low water
The flood tide starts from 2 1/2 hours before high water to 2 1/2 hours after high water.
The minutes in between the change in tide are slack water (i.e. no movement in either direction).
The tidal cycle runs for just over 12 hours e.g. high water today at 12.00pm tomorrow it may be at 12.20pm.

Happy sailing !!