Cross Channel Tides

[bedouin]

If you look at the published tidal streams you would be forgiven for thinking that the tides between the South of the Isle of Wight and Cherbourg ran primarily E/W.

My experience is that in general there is a lot more N/S in the tide than shown on the streams. I also think that that is stronger on the French side than the English (barring of course the tide going round the Island) with up to maybe 1.5kts N/S at springs say 15 miles of Cherbourg. Do others agree?

That being the case when should one leave Cherbourg to make most use of the tides when heading for Bembridge (and on to Portsmouth) ? Let's assume about a 12 hour crossing from the Grand Rade to Bembridge? (but assume a variation in crossing time possibly of an hour or two).

Is it easier if aiming to go through the Needles channel instead (because the W going tide that would be foul from St Catz to Bembridge is fair from St Catz to Needles)?

 

[Sans Bateau]

I always try to plan to arrive at St Cats as early on the flood as possible, the same would apply to the Hurst. You dont want to be trying to get into the Solent via either entrance against an ebb. I have though before now arrived a bit late at the Eastern end, with Chichester as my destination, when the tide has already set E-W, about 2 hours before HW Portsmouth. Knowing that was going to be the case I have shaped a course heading much further East, point at Selsey, then you are clear of the strong ebb around Bembridge and the tide will carry you to your front door.

I pay little attention to the tidal flow leaving Cherbourg, but I would leaving St Vast.

 

[bedouin]

The problem with "as early on the flood as possible" is that it is tricky to do if the crossing time is uncertain; it would be particularly annoying to have a record-breaking crossing to St Catz only to find yourself 2 hours ahead of schedule and therefore pushing a nasty foul tide to Bembridge, even worse you then arrive off Bembridge just as the tide turns and you have to push the foul tide again into Portsmouth (although I don't worry too much about the tide from Bembridge to Portsmouth.

 

[Sans Bateau]

Indeed and we have had crossings so fast that we arrived 'to early' if there is such a thing, but better to arrive to early and have to wait a short time, than to arrive to late and have to stem an angry ebb. IMO.

 

[bedouin]

So why not aim to reach St Catz say 2 hours after the tide turns, so even if you are early you still get the benefit of the favourable tide?

 

[robp]

If you look at the published tidal streams you would be forgiven for thinking that the tides between the South of the Isle of Wight and Cherbourg ran primarily E/W.

My experience is that in general there is a lot more N/S in the tide than shown on the streams. I also think that that is stronger on the French side than the English (barring of course the tide going round the Island) with up to maybe 1.5kts N/S at springs say 15 miles of Cherbourg. Do others agree?

That being the case when should one leave Cherbourg to make most use of the tides when heading for Bembridge (and on to Portsmouth) ? Let's assume about a 12 hour crossing from the Grand Rade to Bembridge? (but assume a variation in crossing time possibly of an hour or two).

Is it easier if aiming to go through the Needles channel instead (because the W going tide that would be foul from St Catz to Bembridge is fair from St Catz to Needles)?

Cheating and using a tidal calc programme to enable quick comparison, optimimum time to leave East entrance on say Tuesday 20th (big spring tide), is 2 hr before lw Dover.

 

[Sans Bateau]

Ok thats fine, that leaves 4 hours favourable tide. If you are delayed in arriving at St Cats by, say an hour, will three hours be enough to clear Bembridge? I guess it probably will if you have say 2 knts of tide with you. But I'd still try to be a bit earlier.