Hull unit with a hydrofoil system and marine vessel

An auxiliary hull unit detachably mountable to a transom on a marine vessel, wherein the hull unit is mountable at least partially below the water line of the vessel and arranged to extend rearwards parallel to a rearward extension of hull sections adjacent to the hull unit, the hull unit comprises a rear hydrofoil system for the marine vessel;

• the rear hydrofoil system comprising at least one pair of foldable hydrofoils which are pivotable in a lateral direction relative to the hull unit, wherein each hydrofoil is controllable by at least one actuator for displacement of the at least one pair of foldable hydrofoils in the lateral direction of the hull unit between a stowed position and a deployed position, wherein
• each foldable hydrofoil comprises a first portion comprising a first end which first end is mounted hinged relative to the hull unit and on opposite sides thereof;
• each foldable hydrofoil comprises a second portion comprising a free second end extending away from the respective first portion towards the opposite side of the hull unit and at an obtuse angle relative to the first portion;
• wherein the foldable hydrofoils are at least flush with the hull unit in the stowed position.