Abstract: A drilling rig comprises a platform (10) supported above a sea surface (14) by legs which extend to the sea bottom (16). A drill guide (30) of rigid open framework construction extends down from the platform to the sea bottom. The drill guide is only minimally affected by turbulent sea conditions because of its open framework construction. A hardenable substance such as concrete (54) is poured into a flexible bag (50) at the lower end of the drill guide to form a solid structure conforming to the uneven sea bottom and having a substantially flat upper surface. Drilling takes place through the hardenable substance and into the underlying sea bottom.

Abstract: A drilling rig comprises a platform (10) supported above a sea surface (14) by legs which extends to the sea bottom (16). A drill guide (30) of rigid open framework construction extends down from the platform to the sea bottom. The drill guide is only minimally affected by turbulent sea conditions because of its open framework construction. A hardenable substance such as concrete (54) is poured into a flexible bag (50) at the lower end of the drill guide to form a solid structure conforming to the uneven sea bottom and having a substantially flat upper surface. Drilling takes place through the hardenable substance and into the underlying sea bottom.

Abstract: A drilling rig comprises a platform (10) supported above a sea surface (14) by legs which extend to the sea bottom (16). A drill guide (30) of rigid open framework construction extends down from the platform to the sea bottom. The drill guide is only minimally affected by turbulent sea conditions because of its open framework construction. A hardenable substance such as concrete (54) is poured into a flexible bag (50) at the lower end of the drill guide to form a solid structure conforming to the uneven sea bottom and having a substantially flat upper surface. Drilling takes place through the hardenable substance and into the underlying sea bottom.

Abstract: A method is disclosed for driving a pile into the ocean floor utilizing an underwater hammer. A leg of an offshore jacket structure is provided with several annular guide sleeves affixed to the leg at several spaced apart locations along the exterior of the leg. A pile is disposed underwater in the lower guide sleeves proximate the lower end of the structure leg. A housing assembly having a hammer mounted inside is lowered from the surface through the guide sleeves and into contact with the top of the pile, with the hammer being beneath the surface. The pile is driven by a succession of blows delivered by the hammer. The housing is then raised to the surface and moved to another driving location by an overhead sling.

Abstract: Anchoring arrangements for structures such as offshore towers. Wedges which fit down into spaces defined by downwardly converging surfaces fixed to the structure and to an anchor member, respectively, are held in frictional locking engagement by means of bias weights. Two sets of wedge type interlocks are provided in longitudinally displaced relationship and are arranged in reverse order so that downward bias forces on the wedges serves to provide locking against relative movement in opposite longitudinal directions.

Abstract: A platform is raised from water level up to the tops of prepositioned template legs by means of jacking units comprising jacking mechanisms and jacking legs mounted near the upper ends of the template legs and extending down to the platform. Bridge beams of open framework construction span the distances between the upper ends of the template legs and these bridge beams provide support for the jacking units as well as reinforcement for the platform when it has been raised.