Mathematical modelling of Spitfire's performance was undertaken at By Design, well before construction had begun. These are two of the performance graphs we generated.
Although testing is still in the early stages, Spitfire is already close to meeting its performance estimates. It 'takes off' (lifts up on its hydrofoils) at around 12 knots - which it can achieve in 10 knots of wind. Once on the foils, the bumping of waves disappears as Spitfire smoothly accelerates up to speeds of 25 knots, in 14 knots of wind; 30 knots in around 20 knots of wind. We expect it to get to its maximum speed (without ballast) of 35+ knots in 25 knots of wind or less. With water ballast tanks fitted, the estimated top speed is above 40 knots.