Abstract: A wellhead structure having a subsea wellhead (10) connected to the lower end of a collet connector (30). A blowout preventer stack (8) is connected to the upper end of the collet connector (30) and a marine riser (13) is connected to the upper end of the blowout preventer stack (8). The wellhead (10) has an outer wellhead housing (12) fixed to the seabed (B) and an inner wellhead housing (14) supported within the outer wellhead housing (12). Upper hub (16) of outer wellhead housing (12) has an outer profile for mating in a releasably locked position with the collet connector (30). External tensile and bending loads are transmitted directly from the marine riser (13) and blowout preventer stack (8) to the outer wellhead housing (12) along load path L2 bypassing inner wellhead housing (14). One embodiment (FIGS. 5 and 6) shows an inner wellhead housing (14B) extending above the outer wellhead housing (12B) and adapted for separate connection to a small connector (30C) shown in FIG.