The invention concerns a method for installing a hatch (34) to a subsea structure (10) by connecting the hatch to the subsea structure by at least one hinge (20) having a first mounting portion (21), a second mounting portion (22), a flexible portion (23) interconnecting the first and second mounting portion allowing a pivot connection between the first and second mounting portion. The installation steps comprise •—inserting a protrusion (23) of the first mounting portion (21) into an installation hole arranged in the subsea structure (10), •—inserting a protrusion (24) of the second mounting portion (22) into an installation hole arranged in the hatch (34), thereby •—engaging the first mounting portion (21) of the hinge (20) for anchorage with the subsea structure (10) and engaging the second mounting portion (22) for anchorage with the hatch (34) thereby arranging for the hatch to pivot between a closed and an open position about a pivot axis provided by the flexible portion of the hinge. The invention also concerns a hinge and an assembly for subsea use.