Hi Maria, If you go to South Africa look up Gary Vos of Hydrospeed, gvos@iafrica.com http://www.hydrospeed.co.za/ We are considering using a Foil assisted hull form on some designs we will start next working on next year. Foils are a wing that sits between the hull to create lift to the boat that reduces wetted surface and allows the boat to plane higher with less effort. They also have a cushion effect on the waves so tunnel slamming is reduced. I have tested a Foil assisted planing cat in NZ, very similar to his and the ride is awesome. If smooth ride at high speed is your goal, I think the Foil assisted hull form is the way to go. They take more fuel in speeds under 20 knots but over 20 knots they become very efficient. The displacement hull form seems to be the most economical under 20 knots so if you know what speed you wish to cruise at you can find the best hull to suit. I have had displacement and semi-displacement hulls before but I never thought there was any point at having a boat that would sit on 25-30 knots all day as the rough water would make it too unpleasant. I was wrong! Imagine sitting on 28 knots heading into 4-6 ft seas in a 42 footer and writing letters, making tea and so on. I watched people do it. The captain of this foil assisted cat delivered a 55 footer where they slowed down from the 30 knot average they were making off the rough coast of New Zealand because the waves reached 13ft. They slowed from 30 knots to 25! Take a ride on a one of Gary's hull forms, you will be impressed. You can also charter a foil assisted planing cat and a non foil assisted sistership from the Moorings Nautic Blue Fleet. The Lion 46 design they have, approx 12 built, half with foils half without. Not sure if they are a good example, Gary Vos will know as he built the foils for them. The foils boost the speed from 23 knots to 32 on twin 370hp engines. http://www.nauticblue.com/fleet_details.asp?fttype=46A4E We are looking at starting production of a 40ft 2 cabin version and 55ft 3 cabin version of this but more modern looking. Also planning a 55ft 3 cabin long range displacement model for ocean crossing, twice the range of the foil cat but lower speeds. Kind Regards, John Winter www.winteryachts.com Ph +64 21 454 107 (Mobile)