R22 Discussion Group

On Jun 27, 2023, at 9:18 AM, Chris Geankoplis <chrisgeankoplis at gmail.com> wrote:

Jeff,

What’s the shaft length and the actual, ready to use, weight?  Assuming at least a long shaft, either motor will work.  I would expect the Mercury 15 would be a little heavy.  Even if the motor mount can handle the weight and power, hanging that much weight off the transom will affect the boat’s trim in a bad way.  Down by the stern fore/aft trim will really slow the boat down.  Think of all the relatively flat wetted surface area aft of the keel back to the transom.  When the boat has proper fore/aft trim, that region of the hull slopes slightly upward to allow the turbulent flow coming off the keel to blend smoothly and flow off the transom with minimum drag.  With down by the stern trim, the aft region of the hull behaves like the flaps on an airplane.  It generates hydrodynamic lift and a lot of drag.  You will literally be converting the part of the sail plan’s thrust into an upward force trying to lift the stern.  This is a good way to make the boat go slow!

For the record, the Rhodes 22 sails fastest with a slightly down by the bow fore/aft trim.

Roger Pihlaja
S/V Dynamic Equilibrium

Sent from my iPhone

The Rhodes 22 Discussion Group

ROGER PIHLAJA

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