Propulsion device for use with a fluid

A propulsion device for use with a fluid, comprising:

• a mechanism including
• one or more cranks rigidly coupled to a shaft,
• one or more connecting rods that are each movably coupled to one of the one or more cranks, the movable coupling to permit rotation therebetween,
• a mast coupled to the each of the one or more connecting rods,
• one or more slide structures or one or more straight-line linkages that operate in conjunction with the mast,
• wherein the one or more cranks, the one or more connecting rods, and the one or more slide structures or one or more straight-line linkages are arranged so that rotational motion of the shaft is translated to a combination of substantially linear motion of the mast between an inner extent and an outer extent and rotational motion of the mast within an angular range between a first limit and a second limit;
• and
• a flexible foil coupled to the mast at an attachment point, the flexible foil including
• a nose portion extending from a leading edge of the flexible foil to the attachment point, and
• a tail portion extending from the attachment point to a trailing edge of the flexible foil.

A propulsion device for use with a fluid, comprising:

• a mechanism for translating rotational motion of a shaft to a combination of substantially linear motion of a mast, between an inner extent and an outer extent, and rotational motion of the mast, within an angular range between a first limit and a second limit, the mechanism including
• one or more cranks rigidly coupled to the shaft,
• one or more connecting rods that are each movably coupled to one of the one or more cranks, the movable coupling to permit rotation therebetween, and
• one or more slide structures having a channel through which the mast extends;
• and
• a flexible foil coupled to the mast at an attachment point, the flexible foil including
• a flexible nose portion extending between a leading edge of the flexible foil to the attachment point, and
• a flexible tail portion extending from the attachment point to a trailing edge of the flexible foil,
• wherein the flexible foil is held substantially perpendicular to a direction of propulsion when the mast is at the inner extent and the outer extent, and at a maximum inward pitch angle or a maximum outward pitch angle when the mast is disposed at a midpoint between the inner extent and the outer extent.