The Hovercraft

Three years ago, Columbia University's Solar Splash team introduced a novel and innovative design to the Solar Splash competition by entering a hovercraft.  The boat is a conventional displacement catamaran during the endurance race but switches to hover mode for the sprint race.  The 2001 Columbia University team encountered many obstacles when racing the hovercraft.  These issues included excessive weight, a weak transmission, and lack of testing.  In 2002, the hovercraft was completely redesigned for better performance.  Although the second generation hovercraft was dramatically better than our previous one, there were still many problems faced by our team.

The primary focus of our team this year has been to build upon the successes of the second generation hovercraft.  This has meant improving the reliability and performance of the mechanical and electrical systems, as well as modifying the shape of our catamaran hulls.

Progress:

First hover test:  The test was a success:  the modifications to the center of gravity have balanced the boat properly and the new Etek motor has proven more than capable of hovering the boat for an extended period of time.  While we successfully used the thrust fan to move the craft, the air rudder steering system was not operational for this test.

 Please click on the following links to see video clips of the test.  Hovercraft starting up     Hover in action

4/9/05  We have begun the process of widening the pontoons.  With the stricter enforcement of the rule against major hull modifications between races we have needed to mount the pontoons in a fixed position (we used to move them between races to switch between hover mode and endurance catamaran mode).   When in hover mode the pontoons have too deep a draft to come out of the water when the boat hovers.  To fix this problem we have decided to widen the pontoons and thus decrease the draft.  We have epoxied a set of ribs to the hull over which we will stretch Dacron.  This solution will not adversely increase the weight and will also not require many man hours to complete.

Here you can see the ribs being epoxied onto the pontoons.

The New Boat

With the hovercraft mostly finished, the team decided that we wanted to try a new challenge.  After looking at several different options the team fixed on building a hydrofoil equipped boat due to the very low drag characteristics of hydrofoils.  Hydrofoils present a unique engineering challenge, especially in Solar Splash where available power is so limited.

This year, the team is concentrating on building the new hull with its associated mechanical and electrical systems.  We will enter this boat in the 2005 Solar Splash competition as a normal displacement mono-hull and in the following year we will work on adding the hydrofoils to the hull.  This two year strategy allows the team to focus this year on designing and testing the boat's systems to ensure they are operating soundly, while leaving the next year to design and test various hydrofoil configurations.

Progress:

The team has decided to build a full displacement mono hull out of foam and fiberglass.  This combination will provide, among other things, the lightest weight possible, excellent endurance race performance (where most of the points are won), and good strength as well as durability. 

Specifications: 16' LOA, ~15.5' LWL, 30"Beam, ~5" Draft.

Computer modeling and analysis has been employed to design the hull and place the components inside it.  Additional physical scale modeling testing has been conducted to analyze lateral stability.  The results have shown that the craft will pass stability inspections at the race, and provisions are being made for stabilization floats on the bow hydrofoil support struts should they be needed.  Our initial model is pictured below with hydrofoils. 

4/15

We have revised the hull design for lower drag: