Container ship cranes

Claim 1

IN A CONTAINER SHIP HAVING SPACED APART RAILS ADJACENT EACH EDGE OF THE DECK PARALLEL TO THE CENTER LINE, A CRANE STRUCTURE ADAPTED TO MOVE ON SAID RAILS COMPRISING A SINGLE MAIN FRAME MEMBER EXTENDING TRANSVERSELY OF THE SHIP, LEG MEANS EACH BEARING ON THE RAILS AT TWO SPACED POINTS, SAID LEG MEANS SUPPORTING THE MAIN FRAME MEMBER AT EACH END AT A POINT ABOVE AND INTERMEDIATE THE SAID SPACED POINTS TO FORM WITH SAID POINTS THE THREE POINTS OF A TRIANGLE, DRIVE MEANS FOR MOVING THE LEG MEANS ON THE TRACKWAY ON SAID SHIP, AN EXTENSIBLE ARM PIVOTALLY MOUNTED ON EACH END OF THE FRAME MEMBER FOR ROTATION ABOUT SAID END FROM A POSITION AT LEAST 90* OUT OF ALIGNMENT WITH THE MAIN FRAME MEMBER TO A POSITION IN LINE WITH AND FORMING AN EXTENSION OF SAID MAIN FRAME MEMBER AND EXTENDING OVER THE SIDE OF THE SHIP, A PAIR OF SPACED RAILS ON SAID MAIN FRAME MEMBER, A PAIR OF LIKE SPACED RAILS ON EACH OF SAID EXTENSIBLE ARMS, A LOAD TROLLEY MOBABLE ON SAID RAILS, HOIST MEANS ON THE LOAD TROLLEY AND DRIVE MEANS MOVING THE LOAD TROLLEY ON THE SPACED RAILS.