[Paddlewise] Wakes (was Planing)

At 5:37 PM -0800 1/17/02, John Blackburn wrote:
>
>This past summer I was paddling the channels in the bay behind Avalon,
>New Jersey.  I noticed that the boats that went past my wife and I were
>mostly thoughtful and throttled back, came down off plane until they were
>past us and then fired it up again.  The wakes from the planers and non
>planers were very different with planers being easier to handle.  What!
>you say, well, it suprised me also!  Some of the larger displacement
>boats (sport fishers) threw out big wakes when off plane, with similar
>sized boats up on plane putting out much smaller waves.  Does this mean
>there is noticeably less energy going into wave formation?  I think the
>answer is yes because when the hull is up on a plane, the hull shape is
>much different with unique wave patterns itself.  Therefore, if there is
>a big transition in wave formation from displacement to planing it seems
>there should be a discontinuity or transition in the speed power curve.
>And that is where planing starts.  I sure wish I still had my old texts
>here so I wouldn't have to do this by memory.

I always appreciate the thoughtfulness of the people who throttle 
down to pass. Their intentions are good and they should be commended. 
I just wish they would get a clue and not do it. As you say, the wake 
they produce is much greater unless they slow down to the point where 
they are going the same speed as a kayak and can't pass.

The whole reason boats are designed to plane is because it reduces 
drag when they are up on plane. Less wetted surface means less 
friction and less boat in the water means less energy wasted that 
goes into waves. The downside is the design that planes efficiently 
is very inefficient at lower speeds and create all kinds of waves.

The upside is if you wait at the mouth of the harbor where all these 
boats accelerate up to speed, you can catch some great waves for 
surfing. The best waves are when they have the trottle pushed all the 
way forward but have not yet gotten up on a plane.
-- 
Nick Schade
Guillemot Kayaks
824 Thompson St
Glastonbury, CT 06033
(860) 659-8847
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