SL33

About

The SL33 is grand prix catamaran designed by Morelli & Melvin in 2011. The original one-design class utilised lifting curved boards for semi-foiling performance downwind. It is of carbon fibre construction and equipped with a 16 metre rotating carbon fibre wing mast. The SL33 marks the genesis for foiling racing boats seen today as it served as the test platform for Emirates Team New Zealand and Luna Rossa in the lead up to the 34th America’s Cup. The SL33 was equipped with hydrofoils for the purpose of testing the concept which later was seen on the AC72. Our boat ‘Excess’ is one of the two Team New Zealand boats. The boat is equipped with asymmetric L foils on each hull capable of speeds well in excess of 25 knots.

It has taken some time to get up to speed on Excess during race conditions. The boat was purely used as proof of concept for foiling technology so there are many aspects that are suboptimal by today’s standards. The asymmetric foils behave drastically differently depending on which tack you are on. The foils themselves are small so it requires approximately 17 or 18 knots of boat speed before the hulls begin to lift out of the water; the rudders are also short with no adjustment available. The boat, like the current generation F50, require a flight controller making constant adjustments to the foil rake to control the ride height. The L foils require a lot of adjustment from the crew to sustain flight and prevent breaching.