A-frame » Click image to enlarge The Allied A-frame being hoisted for installation on Knorr at the WHOI Iselin Marine Facility. A-frame on the stern of Knorr showing tele-boom and Lantec winch mounted atop the frame. A-frame engaged in coring operations during Sea Trials in September 2007. The half height roller sheave has the load. A-frame in the final phase of load transfer to the stern sheave. Lantec winch hoisting the extruder onto corehead during recovery.