A floating platform for supporting generators of power derived from the wind, the waves and ocean currents, adopting an approximately disc-shaped general configuration with a circular or polygonal perimeter, which optimises its size and therefore minimises substantially its weight and likewise its production costs, as well as other associated complexities; which eliminates the possibility of entering into resonance with the movement of the ocean waves and thus not damaging the equipment installed, not overturning, and not surpassing the maximum list acceptable for wind power generators, nor wave power generators, nor ocean current generators; and which withstands the waves of the greatest size possible, all due to a ratio between its depth or height (13) and the diameter (14) thereof of between 0.06 and 0.35.

A floating platform for supporting generators of power derived from the wind, the waves and ocean currents, adopting an approximately disc-shaped general configuration with a circular or polygonal perimeter, which optimises its size and therefore minimises substantially its weight and likewise its production costs, as well as other associated complexities; which eliminates the possibility of entering into resonance with the movement of the ocean waves and thus not damaging the equipment installed, not overturning, and not surpassing the maximum list acceptable for wind power generators, nor wave power generators, nor ocean current generators; and which withstands the waves of the greatest size possible, all due to a ratio between its depth or height (13) and the diameter (14) thereof of between 0.06 and 0.35.

A boat hull includes a serrated keel which is utilized to dissipate local energy and increase efficiency by reducing drag. In one embodiment, the boat hull preferably includes serrations which are teardrop shaped with a ratio of 3 to 1 in that the length of the teardrop cutout is 3 times the depth.

A boat hull includes a serrated keel which is utilized to dissipate local energy and increase efficiency by reducing drag. In one embodiment, the boat hull preferably includes serrations which are teardrop shaped with a ratio of 3 to 1 in that the length of the teardrop cutout is 3 times the depth.

A vessel (1) comprises a hull (2) including a bow (3) and a stern (4) and has a length-to-beam ratio which is smaller than 10:1, preferably smaller than 5:1. The hull (2) has a vertical centre plane (CP) extending in a direction from the bow (3) to the stern (4). At each side of the centre plane (CP) the vessel (1) has at least two azimuth thrusters (6) including respective propellers (6a), which azimuth thrusters (6) are located next to each other in transverse direction of the centre plane (CP). Each azimuth thruster (6) drivably coupled to its own prime mover (7).

A vessel (1) comprises a hull (2) including a bow (3) and a stern (4) and has a length-to-beam ratio which is smaller than 10:1, preferably smaller than 5:1. The hull (2) has a vertical centre plane (CP) extending in a direction from the bow (3) to the stern (4). At each side of the centre plane (CP) the vessel (1) has at least two azimuth thrusters (6) including respective propellers (6a), which azimuth thrusters (6) are located next to each other in transverse direction of the centre plane (CP). Each azimuth thruster (6) drivably coupled to its own prime mover (7).

A grounding skeg for a landing craft configured for stem landing onto, and setting off from, a ground surface, the grounding skeg including: an elongate grounding body having a fore end and an aft end; and a removable pulling propeller functionally connected to the fore end of the body; wherein the pulling propeller is able to drive the landing craft ahead and astern; and the grounding body is locatable on the landing craft such that: the grounding body provides contact with the ground surface during stem landing of the landing craft; the fore end of the grounding body faces a bow end of the landing craft; and the aft end of the grounding body faces a stem end of the landing craft.

A grounding skeg for a landing craft configured for stem landing onto, and setting off from, a ground surface, the grounding skeg including: an elongate grounding body having a fore end and an aft end; and a removable pulling propeller functionally connected to the fore end of the body; wherein the pulling propeller is able to drive the landing craft ahead and astern; and the grounding body is locatable on the landing craft such that: the grounding body provides contact with the ground surface during stem landing of the landing craft; the fore end of the grounding body faces a bow end of the landing craft; and the aft end of the grounding body faces a stem end of the landing craft.

An improved method for building a lapstrake boat 240 includes an improved strake structure 152 having a wide rabbet 182 running the length of said strake's lower edge 164 and inside face and having a selected rabbet width which defines a joint overlap region with a bond receiving gap 210. The strake's rabbet width is preferably three times the plank's thickness 180 along most of its length but may taper. A plurality of temporary tie receiving holes 220 are bored through the thickness of the strake, and entirely within the rabbet segment of the strake for coaxial alignment with adjacent holes 224 in the adjacent strake. Adjacent strakes 150, 152 are aligned and tied together so that the wide rabbet segment 182 in the bottom edge of one adjoining strake 152 overlaps and is tied to a selected surface area on the outside face of the adjoining strake 150.

An improved method for building a lapstrake boat 240 includes an improved strake structure 152 having a wide rabbet 182 running the length of said strake's lower edge 164 and inside face and having a selected rabbet width which defines a joint overlap region with a bond receiving gap 210. The strake's rabbet width is preferably three times the plank's thickness 180 along most of its length but may taper. A plurality of temporary tie receiving holes 220 are bored through the thickness of the strake, and entirely within the rabbet segment of the strake for coaxial alignment with adjacent holes 224 in the adjacent strake. Adjacent strakes 150, 152 are aligned and tied together so that the wide rabbet segment 182 in the bottom edge of one adjoining strake 152 overlaps and is tied to a selected surface area on the outside face of the adjoining strake 150.