Mikael at Candela, the C-7 maker, here. Hydrofoils have a number of benefits, among them are: less slamming (up to a certain sea state), less drag and better fuel economy, and smaller wake. Boeing 929 Jetfoiler from the 1970's onwards and the Russian hydrofoils that were produced in large numbers during the 1950's-1980's largely used hydrofoils because they made smaller wakes (Russian river rockets) or handled choppy water well (Boeing, in Hong Kong and Japan).

At Candela, we use hydrofoils to reduce the energy usage, to be able to make an electric boat that has long range at high speeds, above 20 knots. Conventional hulls are hard to electrify since they need so much power. However, we use a new type of hydrofoil: fully submerged hydrofoils, that are more efficient but needs active stabilization from computers and software. The on-board Flight controller adjusts the hydrofoils at 100 hZ, or 100 times per second, which makes for a craft that won't pitch or heave. This tech was available in the 1970's - it's basically a very similar Flight controller as in an inherently unstable jet fighter like F-16 - but thanks to drones and smartphones, the price reduction of sensors makes it possible for us to offer this tech in a leisure boat.

And - we're scaling our electric hydrofoil tech to commercial ships. Right now, we're starting the construction of the world's first foiling electric shuttle ship for the city of Stockholm. At its launch next year, Candela P-30 will be the fastest electric ship ever at 30 knots, as well as most energy-efficient ship ever built. Energy usage is 1/10th of conventional diesel ships. Check it out here:

https://candelaspeedboat.com/public-transport/