Inflatable hulls generally have less than optimal forms to avail ease and efficiency of planning.
Might I suggest that you utilize a kit to enhance the basic dinghy's capabilities in the form of a LARGE trim tab addition. A discussion with a manufacturer regarding how your craft might work
with various propulsive power plants [motor hp and pitches of propellers] should be enlightening.
Linked below is to one such manufacturer which provides information and videos. I have no affiliation or specific knowledge of any of the trim tab companies, just placing this information as an alternative to all you "go fast" dinghers who desire the use of a light weight outboard motor.
If any of y'all have experience with the use of large trim tabs please advise as to the performance enhancement.
All the best.
MAXI MARINE - Detachable Planing System for Inflatable Sportboats/RIB (Lifters - special trim tabs)
I always get a chuckle at the fundamental concept
that sailors who are fine with cruising long distances at relatively slow speed and with tacking far from their direct line when headed windward, then desire to travel fast for short distances between their yacht and a nearby shore destination
Copied from the referenced website:
radically improve the performance of inflatable boats, lowering initial planning speed while increasing cruise
speed and acceleration 25% to 45% and planing weight capacity up to 30%, while decreasing fuel consumption
by over 25%. Boats having insufficient power or carrying heavy loads can now achieve plane or achieve higher planing speeds. Lifters are specifically designed and patented for Zodiac
type inflatable boats to yield maximum performance.
The speed and weight carrying capacity of a planing hull is directly related to it's planing surface area and driving power. Unlike small trim tabs, Lifters add more that 5 times the planing area, or a substantial 4.2 sq. ft. (12.5" x 24" x 2) of additional hull planing surface as shown below
. At low planing speeds the additional surface area at the stern creates more than a proportional amount of added lift
by pushing water
down, opposed to the forward "V" section which pushes water to the sides. The additional lift
far aft of the center of weight (boat, crew and motor) lifts the stern and lowers the bow for more hull planing surface area and upward lift rather than backward drag. Lifters also generate less drag and more lift then trim tabs by having a lower angle of deflection or attack and more surface area further aft. At high planing speeds when less surface area is desired because of higher viscous skin drag, the ventilation slots at the front of the Lifters suck air into the mini step which decreases the planing surface area and drag. This technology is similar to the latest side ventilated stepped hull technology used on race
and recreational boats, but more importantly, Lifters dramatically increase the performance and comfort for fishing
, hunting, scuba diving
, tending, towing, rescue
and other boating