On 10/25/2015 11:44 AM, Justan Olphart wrote:
On 10/25/2015 11:28 AM, wrote:
On Sun, 25 Oct 2015 02:07:43 -0400, wrote:

On Sat, 24 Oct 2015 18:35:50 -0700 (PDT), wrote:

The claim is quite true and I have seen it many times, but I don't
think it's as complicated as some make it sound. It can happen in
deep water and without wind. In 1992 my eureka moment came one day
while heading east on a motor yacht through the Current Rock passage
in the Virgin Islands where I had a birds-eye view of whole effect
clearly displayed in front of me. I could see that the current
causes the waves in the center to travel a little slower than on the
outsides, and that this bends the wave train, and now the waves on
the left and right were converging towards the center where they
added their energy and height. Depending on the location, the effect
can be spread over a large or small area I have illustrations here
http://www.3dym.com/waves/waves.htm

Where we see it all the time is in a pass or mouth of a river when you
have an onshore wind (from sea to land) smacking into an outgoing tide
or current, the waves will be a washing machine on steroids. If you
can hug the shore and get out of the current it will be reasonable as
long as you don't run aground..

===

Yes, that's very common. The inlets all along the Atlantic coast are
particularly dangerous under those conditions except for the ones with
big breakwaters. We've also seen it in the eastern Caribbean where
the trade winds create big easterly waves but the gaps between the
islands are tidal. You can be going along in the normal 3 to 6 ft
seas and suddenly see a patch of white water ahead where the waves are
breaking and twice as high.


Mr Luddite can testify to that.


North River inlet? Yup. Bad experience there. Jupiter Inlet in
Florida can be worse though. A 55 footer capsized a few years back
trying to get in.