RE: [Paddlewise] built in rudders

Thanks John and Matt for the explanations.

Until now I had only heard the term hull speed used to describe the dimishing returns for paddling effort as boat speed increases. I certainly appreciate your description of contributing factors.

The end of the hull adjacent to the rudder doesn't taper to a sharp edge but is several millimetres thick and a sliver of deck also overhangs the rudder so removing the rudder might produce the separation drag that Matt mentioned. Perhaps the optimal strategy for combining manoeuverability with speed is to allow the rudder to move freely with no control from the feet, rather than simply remove it. Fixing it in the "dead ahead" position sounds as if it would produce the best speed at the expense of manoeverability on flat water. In practice I've crossed the cables and press the rudder hard over with the leg thats not pushing the deck at the same time as edging.

Of course most of the time this is pretty academic but in the event of a cable failure in a race it could be worth thinking about. (Our 110km Hawkesbury Classic is coming up in a week or two!)

John, your technique for determining effective waterline length was intriguing - I googled Professor Inverbon's dissertations but couldn't find anything that sheds any further light:~)

All the best, PeterO
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