On Sat, 07 Jan 2006 23:23:44 GMT, "Roger Long"
wrote:

From the perspective of one who occasionally has to consider speed and
resistance of boats professionally, I really doubt that the dinghy is
costing you half a knot, at least not on the 32 foot size boats
considered in this thread.

I did some testing on my old Cal-34. Speed loss depended a lot on
wind speed, point of sail and towing method. Half a knot is quite
plausible going to windward in light air, much less likely in 20 kts
of wind on a broad reach. We found that the most efficient towing
with our inflatable was with the bow elevated very close to the
transom. Also keep the dinghy as light as possible when towing.