The Ellipsis… IOM represents a different approach to what is now “conventional chine” boats,
The truth is chines do not do what designers say they do. They do not “grip” the water or generate lift, or stop the boat going sideways in any way.
The main application of a chine on modern IOM’s is to easily allow a boat to have tumble home aft by separating the topside shape from the bottom shape. This aft tumblehome In combination with much fuller bow sections, reduces the “in out wedges” of a hull which stops the hull from trimming bow down when heeled. This hull “balance”, allows the hull when heeled to sail in a straight line rather than curve to windward and allows the foils to stay at an optimum angle of a attack without further skewing the hull. This makes the boat easier to sail and reduces drag.
Other effects of the chine are the ability of a designer to make the stern sections flatter than they otherwise would be and gives the hull a volume bump just above the waterline increasing initial form stability and at the bow increasing acceleration. The chine may also allow a cleaner separation of the water flow aft at speed, but this is debatable.
The Ellipsis… approach is to remove the chine completely but to retain the volume distribution and excellent hull balance of a chine boat. This produces a much simpler and easier to produce hull in both glass and wood. The Ellipsis… is very well balanced upwind and can be trimmed to give a negative feel right though the useful range of heel angles. When running the Ellipsis’s full bow gives the boat excellent nosediving prevention ability and exceptional acceleration in gusts.
The Ellipsis… being narrower on the waterline and has less immersed hull surface than many chine boats. The deck is slightly wider allowing a wider stay base and better rig control. The flat deck with a raised “bubble” section allows the jib foot to be very low in the boat.
The Ellipsis… is also unlike many chine boats, and very pretty boat.
Assembled Ellipsis IOMs, ready to rig and fit radio are now available from ARS Composite Freelancer in Thailand.
These cost $900US plus delivery and can be ordered by contacting: