Aerodynamic and Hydrodynamic Performance
design for Powerboats

We have developed a unique analysis technique that allows designers to see the delicate balance between lift/drag forces of a vee-pad hull.  The method can isolate the lift/drag forces for vee-pad, vee (bottom) surfaces, aerodynamic surfaces and lower-unit appendages.  The technique gives designers, builders, owners and operators the ability to optimize vee-pad dimensions and setup to fine-tune the lift gained from the "pad" portion and "vee surface" portions of hull design.

The VBDP© software employs the unique "Vee-Pad design optimization" technique and provides detailed performance prediction results and graphic performance output that allows for easy 'balancing' of vee-pad/vee surface load distribution for any vee hull design/setup arrangement.

How it Works
Some "Vee"-bottom boats have a flat surface at the very bottom (keel) called a "pad."  This pad allows for more planing surface aft, and while there is a corresponding sacrifice of some softness in ride, this modified vee-type hull design allows for super-fast speeds!

The pad is a relatively flat planing surface configured to the aftmost section of a vee shaped hull.  The pad (or low deadrise center-section) usually extends sufficiently forward, so that the transition from the vee to the flat running surface is gradual, and usually exhibits some deadrise in the forward section of the extension. 

The pad has several performance advantages:

Balancing Act - the high-performance vee-bottom can be a challenge to drive at high speed.  Deeper vies  (15°–20°deadrise)  must be balanced on a thin keel edge, often exhibiting  an unsettling  lateral instability, as it “rocks” from side to side.  The pad provides a wider platform on which the hull will ride - making it easier to balance at higher speeds.

High Lift - The flat pad generates much more efficient Lift than the veg'd bottom shape.  Hydrodynamic theory dictates that, in general, a steeper angle of vee (e.g. 20° deadrise)creates less Lift than a shallow angle (e.g. 10° deadrise).  The extreme case is the completely flat pad that has zero (0° deadrise) that creates very high Lift for it’s small wetted surface area.  The result of this “extra Lift” is reduced hydrodynamic Drag and more speed!

During acceleration mode, the pad vee hull gets Lift from the vee-hull sections, as well as the flat pad section.  It needs this entire lifting surface at lower velocities, to Lift he weight of the hull.  As the speed increases more and more, the required Lift is generated more by the flat pad, and less by the vee'd surfaces.  The pad takes on more of the Lift, and more of the vee'd surfaces become “unwetted”.  Now there is LESS drag, and a resulting speed increase is quite noticeable.  Experienced pad-vee drivers will recognize the “pop” that occurs when the hull reaches that special velocity where the hull “breaks” away from the vee'd lifting surfaces and rides on the pad alone.