The marine pipelaying system for vertical or near vertical laying of an offshore pipeline (20) includes a main supporting structure (5); a pipe connecting station (30), wherein a pipe section (21) is connected to an uppermost end (20a) of a previously launched pipeline; a static clamp (35) adapted for releasably securing the uppermost end of the previously launched pipeline, wherein the static clamp is adapted to support the weight of the previously launched pipeline; a mobile clamp (40) adapted for releasably securing the previously launched pipeline at a position below the static clamp, wherein the mobile clamp is adapted to support the weight of the offshore pipeline as the offshore pipeline is released from the static clamp; and a mobile clamp hoist (10) connected to the mobile clamp.