It baffles me that we are using nautical arguments, and I'm not referring to 80kt here but more the Rec Pilot community at large. The discrepancy and misuse of such terms is alarming.
Boats use a displacement method of buoyancy. Moving through the water when displacing a large volume of water is inefficient in general at speed, and is avoided by using a hull design that allows a craft to skip, or plane, over the water once at speed. Like boiling water, a relatively large amount of energy is expended reaching plane speed, and therafter a relatively small amount of energy is expended maintaining it.
Aircraft, on the other hand, move through the air in a relatively linear (energy expenditurely talking) way for a given attitude. Attitudes outside normal cruise are inefficient only because you will be increasing the angle of attack and approaching stall. Often it is more efficient to cruise at a slower speed then you may otherwise, or than the craft is capable of. Consult your POH for figures on cruise speed, fuel burn, and max range speed.
Please, everyone, stop using boats as an analogy. They are not aircraft and do not behave like them.
- boingk