The first problem to overcome when piloting an hydrofoil is the takeoff which requires to reach an important velocity so that the lift could exceed gravity forces. This must be accomplished in the same condition as a classical ship that is to say with the hull partially submerdged source of drag. To compensate for drag which presents a great increase during the takeoff will require a more important properlling power than during the "flight".
The required power also depends on weather conditions; in a rough sea, the Navy recommends to plan a 20 to 25% power margin.

Navigation with an hydrofoil
Piloting an hydrofoil gets from traditional navigation and the piloting of a plane. Actually, an hydrofoil pilote has to take into account the altitude of the ship and to act on lift to optimize stability and improve its performances. these changes of the intensity of the lift can be obtained without the pilote's intervention or an electronic control system (when using surface piercing foils) and/or by using, like in aeronautics, flaps or a change of the attack angle (which would correspond to an upward or downward tipping of the plane in aeronautics).
When flying at a constant velocity and is equiped with an automatic control system (an electronic system when using fully submerdged foils), an hydrofoil is far more stable than a traditional ship and enable faster and more comfortable turning.