Twin Ducted Fan Driven Boat. 14 April 2009

revised 25apr09

Overview: This is an effort to use my "Displacement Drive" in a water craft. I've drawn quite a few hull shape alternatives and have maintained the overall intention to get the craft fully out of the water when moving at speed. I've greatly enjoyed the designing process, however I must admit that the lack of practical knowledge with boat design is a bit of a worry.

This boat is driven by air pumped at high volume through twin ducted fans at the front of the craft, down and out between it's belly and water surface. It's hull is splayed out widely as a wing to help capture air below it thus lifting the boat from the water by "wing in ground effect" I speculate we 'll get most of our lift from a large negative pressure bubble above the craft.

It's dimensions are 5 metres long, 3 metress wide, with a height of 1.75 metres. Illustrations below.

Front view we see it's true width and height, notice the splay in the hull and three rudders at the back.

To date (14april09) I have yet to simulate it's CFD, also need to further consider it's steering and trim surfaces.

revised 25apr09 I've done a sim drawing for this now and have found that the intake scoops are making negative pressure fields over the craft's entire skin and the floor below. This is good for it's upper surfaces, but bad for the underside of the craft.

Simulations setups:

• Forward speed of craft 100km/hr
• Forward scoop inlet pressure at -1200 pascal
• Craft elevated off floor surface by 120 mm

Note that the simulation drawing is a little different / refined to those made on the 14th april....

The following drawing shows the only volumes of positive pressures on the outer skin of the craft.

With control surfaces in place, the direction of air intake and exaust can be modified. This will become our first look at steering and trim for the "Displacement Driven" boat. The drawing below shows what is in the sim. drawing at the moment. Rotating it's leading edge upwards is anticipated to shift the balance of pressure fields above and below the craft.