So here is something to think about from Warwick Collins, designer of the tandem keel…
In marine design, the speed of displacement hulls is limited by the hull wave generated by the forward motion of the hull. An upper speed limit is reached in which all additional forward energy applied to the hull merely increases this hull wave. Unless a hull can break out of this hull wave, and start to "plane", the hull displacement speed is the effective limit of its performance.
The Holy Grail of marine design is the reduction of the hull wave. Given the energy savings, great efforts have been made to reduce or ameliorate the hull wave. In cargo vessels and tankers, for example, the large forward underwater bulb represents an effort to reduce the hull wave by generating a wave whose trough coincides with the bow wave of the hull and so acts to reduce the hull wave. When successfully achieved, this can result in savings of 12-15% in fuel efficiency.
The most effective solution of all, if it were possible, would be to create a displacement hull form which does not generate a hull wave, or which reduces the hull wave to minimal proportions.
The Universal Hull, developed by Warwick Collins, a yacht designer and inventor, has achieved a form which does not generate a significant hull wave. The hull wave has been reduced to the point where it is hardly perceptible. These virtues have been achieved in a large, capacious, sea kindly shape which is highly tolerant of a wide variety of loads.
Collins and his collaborators have begun to demonstrate this with an 18 foot 6 ins prototype measuring 18 ft LWL and 7 ft beam. The hull has only recently been launched, but the attached preliminary amateur sequence on youtube indicates some these virtues:
The hull displacement speed of an 18 ft hull is 6 knots. Notice how the prototype, driven by a small 15 h.p. outboard, accelerates effortlessly through hull displacement speed to a full plane at 16 knots. Notice also how, manoeuvring at 16 knots, although there is a normal wake and rooster tail, there is no detectable hull wave in the form of a bow wave, mid trough, or quarter wave.
Apart from a huge saving in energy, the hull form is environmentally friendly, because it does not generate significant waves in restricted marine environments and waterways. During the filming of this sequence the photographer was standing on a low floating pontoon a few inches above the water. With the prototype rushing past 20 ft away at 16 knots, the photographer reported that the disturbance produced by the hull did not even wet his shoes.
In principle, the Universal Hull form is applicable to virtually all classes of vessel at all sizes, from dinghies to super yachts, from working boats to cargo carriers, from civilian craft to warships. It represents a revolutionary, and widely applicable, advance in marine hull design.