a suction chamber bounded by: (i) a circumferential outer wall, (ii) an upper wall having a central opening, and (iii) a wall of an internal housing;

the internal housing defining a passage in communication with the central opening for receiving wellhead components that may be secured to the suction anchor;

the suction chamber having a minor upper portion and a major lower portion, and the minor upper portion is smaller than the major lower portion;

the minor upper portion comprising internal reinforcing members extending along the inside of the upper wall from the outer walls to the internal housing, wherein the internal reinforcing members are located only in the minor upper portion and do not extend into the major lower portion;

the major lower portion being adapted to be embedded in a seabed and the minor upper portion being adapted to project from the seabed when the anchor is installed, wherein the bottoms of the internal reinforcing members lie on an upper surface of the seabed when the suction anchor is fully installed;

wherein the internal reinforcing members serve both to reinforce the upper wall of the suction chamber against collapse and to rigidly support the internal housing such that it may resist forces applied to it arising from bending moments applied to a wellhead component received and secured therein; and

wherein the minor upper portion is bounded at an upper end by a planar lid and support ring, and an inner pipe support ring is provided at a lower end of the minor upper portion.