Re: [Paddlewise] question for the hydrodynamics experts...

Robin,

I can't explain the physics but can tell you that the same thing happened to a ship thousands of times your size (the S.S. New York if I recall) when the Titanic started out from port.  The ship was ripped from its moorings and thrown out into the bay, nearly causing a collision.

The same effect is used to trigger certain types of anti-shipping mines, like those the Navy put into Haiphong harbor about 30 years ago.

I have not found any advice in any of the kayaking books regarding safety in a channel when large ships are around except to keep out of their path.  I was wondering about this as I kayaked down the Westpoint Slough with a heavily laden ocean barge moving ahead of me on a parallel course, at roughly my own speed.  Should I attempt to pass it, stay even with it, pull in directly behind at a safe distance, surf its wake, or what?

jerry.

jerry.


At 10:24 PM 10/12/1999 -0400, Gratytshrk_at_aol.com wrote:
>Hi yall,
>I have a question about a bizarre (and somewhat terrifying experience) i had 
>today.  I was fishing in a canal in southeast louisiana today, approx 1/2 
>mile wide with a very deep channel through the center, which probably planes 
>out towards the sides which are surrounded by marsh and other smaller canals. 
> I was having a great day of fishing and after one spectacular cast i 
>happened to look up and see a huge freighter coming down the channel.  I 
>expected a large wake from the ship and it was too near to do any major 
>maneuvering, so i kept my kayak near the side of the channel ( an ENOURMOUS 
>mistake!!)  While the ship was about 1/8 of a mile away all the water from 
>near the sides began rushing out toward the ship.  I was in about 4 ft of 
>water which drained to the bottom in about 20 seconds.  The force of the 
>outrushing flow was greater than any undertow i have ever encountered.  This 
>is when i realized i was in serious trouble.  My kayak rushed out toward the 
>ship (which was at least 1/4 mile away)  Soon a wave of returning water and 
>ship wake (which was at least 2-3 feet above my head from where i was sitting 
>in the trough, I would estimate it at 6-8 feet) was rushing back toward the 
>bank, as i was rushed toward the wave.  The outrushing water and inrushing 
>wave collided to form a huge breaker which crashed right on my face.  In my 
>current state of terror i somehow managed to remain upright through the 
>massive breaker and the slightly smaller wake waves which ensued.  Everything 
>under my deck bungies was washed about 2 feet up on formerly dry land, then 
>returned when the water level returned to normal.  I was soaked, and i am 
>still picking dirt out of my teeth.  I was very lucky to be wise enough to 
>have my pfd and srayskirt on.  My question is this- What force contributed to 
>the outrushing water before the ship reached my location.  I theorized that 
>if anything the ship should displace water would raise the water level.  Or 
>could it be that the propeller acted as a vacuum of sorts that sucked water 
>ahead of the ship by forcing it through the prop and displacing it in the 
>form of a wake behind the ship?  I am totally fascinated by this incident.  
>After the ship passed i decided to call it a day and happened to notice 
>another equally large tanker coming through the canal.  I decided to hide in 
>a side canal and paddled back about 1/2 mile into a canal and thought i could 
>hide around a couple of bends.  I was amazed to see the same effect occuring 
>as the ship approached, I rushed back into the middle of the side canal and 
>again faced some serious waves although not nearly as large.  These were only 
>3-4 feet and did not break.  I understand that the shape and break of the 
>waves had to do with the depth of the water where i was.
>Thanks for any input.
>Robin Lovelock
>New Orleans.
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