How big is a 3 foot wave ?

Thanks for all your quick responses and amazing, for once all in agreem.
ent.

I thought I must have missed something when a 30 knots wind only produces 2.5 ft.

I guess it may change soon .
 
The height is not the only issue , its also the distnace between them?

We have been in a big swale about 6-7 foot waves every say minute and it was fun surfing down the waves towarads flushing doing about 15 knots in a boat that normally cruise at 8.

An other time we are coming back from Belguim same height of waves but not much distsnace between, did we get wet !


Tom
 
Wait 'til the tide changes in about an hour's time! It is currently wind with tide, at 30 odd knots wind over tide it should make for an interesting sea for all those contemplating a weekend booze crooze.
 
The height of a wave is measured from the trough in front of the wave to the peak. This gives a higher wave height than measuring to the trough behind it, although in open sea the difference would be negligible.

For waves breaking on to beaches the wave height measured from the front can be double that measured from the back. There is a macho element in surfing (so maybe in boating) that will understate the wave height on any waves they have been seen on, so that they can overstate the wave height when they haven't been seen.

That said its my view that waves seen from a surfboard or small boat always look much bigger than they are, a true 3' wave is actually a reasonable size and would be considered quite rough by most people. I believe motorboaters who think they have been caught out in 15 - 20 foot waves are usually mistaken, those wave heights are generally only seen mid ocean.
 
I well remeber being off Lands End on a lee shore to boot, at night, and the only safe way to go was SW. Storm jib and motor. but later when well clear of those rocky bits we turned and ran before it. Exciting to say the least, Daylight and those seas were huge, On a 50 footer, in the trough, no wind at all but the cross trees were about 35 ft up the mast, and those seas seemed to be pretty near that height. But as has been posted here, its the shape that matters, These were rollers, just the tops being blown off. This boat had a longish counter stern, so there was a lot of lift there as a wave came up under us. The ride down the back od the wave needed a lot of concentration as a b roach would haave had unpleasnat consequences, Yseteday out in an 18 ft power boat, even those very small Irish Sea pobbles were far more bouncy,
It's all in the game though.
Drewstwos.
 
Can I suggest a December crossing of the Golfe of Lyon in a 40mtr gin palace. Throw in a force 11 Mistral out of nowhere, and your 3 foot wave becomes a 20ft wall of rolling chaos, short, steep and very very wet!
Give me the Solent any day, (or night.)
 
[ QUOTE ]
I believe motorboaters who think they have been caught out in 15 - 20 foot waves are usually mistaken, those wave heights are generally only seen mid ocean.

[/ QUOTE ]

What about the wave that smashed through the front windows on Brittany Ferries 'Pont Aven' last week? The skipper estimated them to be 40ft.

And the old St Columba on the Holyhead - Dun Loaghaire run fifteen years ago hit seas 25 miles out of Holyhead which were landing solid water on the bridge, caused numerous injuries to the passengers, and wrote off virtually every vehicle aboard. I do not know the estimated wave height that time, by St C was one of the larger car ferries of her day.

I can remember standing on the boat deck of the old SNCF "Arromanches" on Newhaven - Dieppe unable to see over the bigger waves back in the late 50s - the 3 hour crossing lasted five hours, while the return ferry coming the other way took 11 hours before she could get in to Newhaven.

Watching the wave boy data in the channel, wave heights of 20 - 25 feet are regularly reported offshore as anyone who has tried to make Cherbourg during in a strong wind over tide situation will confirm !
 
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