VERTICALLY MOVABLE MARINE WORKING PLATFORM STRUCTURE HAVING VERTICALLY MOVABLE GROUNDABLE SUPPORT FRAMES

A vertically movable marine working platform structure is disclosed, which includes a working platform supported for vertical movement on parallel support frames individually comprising a plurality of parallel disposed vertical chords, each two adjacent chords being connected by a number of horizontal members. The platform has recesses on its upper face which accommodate jack housings, the support frames passing through the jack housing and platform. The support members have upper guides in the jack housings and lower guides in the platform, the guides individually having a length at least equal to the pitch of the horizontal members connected to the chords. The guides of the working platform being of such relatively great length, horizontal forces applied by the guides to the support frame are concentrated mainly upon the horizontal members, concentration of loads being avoided upon portions of the chords lying between horizontal members. The recessing of the jack housings into the platform provides a robust and economical structure.