Abstract: Piles are driven underwater by feeding them through spaced apart, aligned, tubular guides mounted on a structure to be anchored by the piles. When the piles reach the sea bed an elongated follower is fed down through the guide sleeves to the top of the piles. A compressible fluid driven hammer is arranged to drive against the upper end of the follower which in turn drives the pile. The submerged depth of the hammer at the upper end of the follower is less than it would be at the top of the pile and accordingly the exhaust pressure at the hammer is minimized and the hammer effectiveness is enhanced.

Abstract: A pipeline is installed by forming a ground surface below the desired grade of the pipeline, holding a pipe length at the desired grade while injecting a hardenable fluid material into a bag positioned between the pipe length and the underlying ground surface so that after the material hardens the bag provides a temporary support for the pipe length at the proper grade and thereafter installing a permanent support by placing hard granular material between the remainder of the underside of the pipe length and the underlying ground surface.

Abstract: A pile driving system for driving piles into an underwater surface which comprises an elongated two-part housing having a casing disposed within the lower portion of the housing and movable with respect to the housing. The casing has a pile driving hammer assembly disposed within the casing and the casing is independently suspended within the lower portion of the housing whereby the hammer assembly may be engaged with the pile and impart a series of blows to the pile, while the housing remains substantially stationary with respect to the underwater surface.

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: An underwater hammer, of the gas discharge type, is provided with a surrounding casing arranged in the nature of a diving bell from which liquid can be purged so that the hammer ram may move up and down with minimum resistance. A reflood tube extends down through the upper end of the casing and opens into an axial reflood passageway in the ram and liquid is pumped through this tube to obtain reflooding after each cycle of operation.

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: An underwater hammer, of the gas discharge type, is provided with a circumferential control valve on the hammer ram to allow free flow of water and gas upwardly along the ram in the annular clearance between the ram and a tubular sleeve in which it is guided, but to interrupt the flow of water downwardly along the ram. The control valve allows the region under the ram to be purged of water when the ram is driven upwardly in the sleeve and it prevents water thereafter from flowing back down under the ram where it would otherwise cushion ram impact on an anvil.

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. 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.

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.