A 10 ft. dink will have a theoretical hull speed of ~ 4kts. Once the dinghy goes much above that value the drag will become exponential, and you should be able to see that on a load cell.
Lifting the bow of the dink by the angle of dink's painter (dink closer to the mothership and its bow lifted) should promote better surfing and semi planing .... for less drag.

1/2+ knot of parasitic drag is not unreasonable, less drag value if the dink is surfing down the mothership's stern wave; or, its bow is lifted on a short painter to keep it semi-planing with less wetted surface area immersion.