Abstract: A windmill speed limiting device is provided to prevent the windmill blades from going too fast during conditions of heavy winds. In order to slow down the windmill blades, the tips of the blades are turned relative to the main blade portion at high speeds. After the tips are turned, the windmill blade must return to a safe speed before the tips are returned to their normal position. A hysteresis effect by which the tip portions are rotated to their normal angular position in alignment with the main blade portion is implemented by means of a cam track, a pivot point below the center of the blade and a central spring loaded drum to which each of the blades are connected.

Abstract: Attempted boat theft is detected by measuring the increased displacement of the boat caused by the added weight of the thief. The device measures the slight sinking of the boat into the water under the added weight and automatically resets so as to be in readiness for responding to the next person.