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Old 29-01-2009, 07:22   #16
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... I would like to learn about the dynamics of waves in different depths...
Many of your questions are answered at:
Oceanography: Waves ~ by Dr J Floor Anthoni
Theory and principles of waves, how they work and what causes them

Oceanography: waves
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Old 29-01-2009, 07:32   #17
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Last time I crossed from Bimini to Miami on my Corsair 31 folding tri it was 15-20 from the north with 8 ft seas...We averaged 10 knots of boat speed.

With your boat I would go in anything less than 20 from the north and 8ft seas.

It is not nearly as bad as people make out...but we once did it in 30 knots from the north east and got our asses kicked.

Phil
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Old 29-01-2009, 08:25   #18
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Hey Bill,

I'm planning to make the crossing from Biscane bay through Angelfish Cut on over to Bimini the last week of Feburary. Going to cruise Bimini and the Abbicos for a couple weeks weather permitting. If this coinsides with your plans your welcome to follow us across. I'm not claiming to be an expert but I've made this crossing several times.

Tim
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Old 29-01-2009, 08:25   #19
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The oil thing is pretty slick! Oil kills the friction of the wind over the water. Less friction = fewer waves.
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Old 29-01-2009, 09:44   #20
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How does shallow depth cause waves to crest and overfall? Is this the result of the bottom coming up fast?

Are all waves the same shape / profile in very deep water or is do their characteristic change at they get larger?

What makes waves of the same height have different "periods" from crest to crest?

Why don't steady winds continue to increase the size of waves? I realize that there is a limiting factor?


How does an oil slick actually prevent waves from breaking?

Explain waves
I really couldn't answer all that without writing a book. But heres a few answers -

Oil has a much higher surface tension than water.

The size of the ocean directly relates to the frequency of the waves; count the waves in Hawaii and they'll be less /minute than you get in Florida.

A light sustained wind in a constant direction will continue to increase the wave size (up to a point)

A tsunami would be barely noticeable in deep water, its the shallows that concentrate all the lateral force vertically.

But if you really want to understand all those questions, you need to buy a book...
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Old 29-01-2009, 11:32   #21
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My wife and I have been crossing to and from the Bahamas since 1975. We often wait for a nice weather opportunity from Lake Worth Inlet to head for the Bank just south of Memory Rock, but if there's winds up to 15 from the north we'll cruise down to Lauderdale and ride with the 'stream up to West End after the winds have clocked. We don't favor big bucks at marinas, so if we end up in Lauderadale we will take a Las Olas mooring, one night anchor in the little lake south of Bahia Mar or a $50 dollar slip for a night up the New River at Cooley's Landing. 'take care and joy,
Aythya crew
This is a great example of how to use the winds and position yourself for an easy crossing. It also has the advantage of not having to deal with all the ICW bridges.

One thing I'll add: I often have used this same strategy, but I'll wait up in Palm Beach, anchoring for free until the winds have finished their NW thing are moving to the NE and are forecasted to soon move back to their prevailing SE. Then I'll ride the last of the NE-E wind down to Fort Lauderdale and likely not have long to wait for the lighter SE winds to cross on. Last I was there, one could also spend one night anchored in Lake Syvia and you are more likely to then find a mooring available earlier the next day if you need it than you are late in the day you arrived from Palm Beach.
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Old 29-01-2009, 13:01   #22
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slick is right

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Originally Posted by starfish62 View Post
The oil thing is pretty slick! Oil kills the friction of the wind over the water. Less friction = fewer waves.
Slick is right!
Makes sense but intuitively I would have thought that it had more to do with things like surface tension.

I'll probably not cross until early in March. We are still planning things and I've still got a bunch of boat repairs and upgrades to do. I'm not overly worried about the crossing, I just play the game of looking at weather and figuring out crossings and timing. For example, it looks like tonight would be a good night to cross to the Bahamas but it's going to be cold and the ocean is going to get nasty over the weekend.
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Old 01-02-2009, 06:01   #23
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Thumbs up Crossing Gulf Stream

FYI - I crossed on Thursday last week to Bimini. Winds out of SE and S at 15, waves started out as 4 moved to 2-3, took 8 hours from Coral Gables to Cat Cay holding 125 degrees. My first Crossing and it was great!

Cleared Customs at Cat Cay, very easy. Check fuel prices and fuel is $3.13 per gallon.
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Old 01-02-2009, 14:35   #24
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Shawn,

Sounds like you planned it just right! Always a good thing on your first time! And an easy customs experience is just a nice bonus.
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Old 01-02-2009, 16:14   #25
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FYI - I crossed on Thursday last week to Bimini. My first Crossing and it was great!

.
Congratulations Skipper!!!.....Hope you have many more...
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Old 01-02-2009, 20:15   #26
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... now your hooked for life mate!
Congratz!

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Old 09-02-2010, 08:04   #27
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Everything I've read about the oil slick method spoke about surface tension. I don't see wind friction as plausable. Maybe I'm mistaken though...
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Old 11-02-2010, 08:21   #28
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Its wind friction that causes waves. Oil reduces friction.
By the way, crossed gulf stream in my 27' columbia in December. In Bahamas now!
P.S. - Need rollerfurling!!! P.M. me plz if you can help!
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Old 11-02-2010, 09:03   #29
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Everything I've read about the oil slick method spoke about surface tension. I don't see wind friction as plausable. Maybe I'm mistaken though...
Quote:
Originally Posted by Captain Jaz View Post
Its wind friction that causes waves. Oil reduces friction.
By the way, crossed gulf stream in my 27' columbia in December. In Bahamas now!
P.S. - Need rollerfurling!!! P.M. me plz if you can help!
Re: Oil, it's not friction, it's surface tension.
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Old 11-02-2010, 09:44   #30
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One important thing no one has mentioned is that the quoted forecasts are for near shore waters and are not indicative of what will be found in the Gulf Stream itself. So the 3 to 5 near shore will be quite different inside the Stream, and most forecasts indicate that wave height is higher in the Gulf Stream. We have made many crossings and never had any reason to make it in uncomfortable conditions. We are out to enjoy ourselves and not to test our stamina. So we patiently wait and enjoy this side of the Stream until we are comfortable with the conditions. WG
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