Positioning method and apparatus for submersible pile driving

Abstract

A pile driving apparatus to be lowered onto the head of a previously submerged pile positioned in a caisson is guided in its descent on cables. The cables are secured to a crossbar attached near the head of the pile. The crossbar must be attached sufficiently close to the head of the pile so that the funnel shaped mouth of the pile driving apparatus is guided onto the head of the pile even if the surface ship has drifted laterally to pull the cables away from the vertical, or if the pile itself is positioned in the caisson at an angle to the vertical. The crossbar is attached to the pile by retractable pins extending through longitudinal slots in the pile, or by extendable pressure pads that engage the circumference of the pile. Means are provided for automatically retracting the pins or pads whenever the crossbar bears against the pile driving apparatus.

Dependencies are inferred from the claim text.