The new component of the Versabuoy system is the Articulating Joint connecting each of the hulls to the topsides. Articulating connections themselves have formed a staple of automotive and other machine equipment and as such there is a large body of knowledge and experience in their design and specification. For current Versabuoy applications under consideration the articulating joint must transmit an axial thrust of between 1,000 and 2,500 tons and accommodate a range of motion of +/-20 degrees. The joint is located at an elevation of (+) 55 to (+) 60 feet MSL, outside of the splash zone and accessible for regular inspection.
Plate 3 shows the fabrication of Fabrication of Pin-in-Pin Articulating Joint being manufactured for use in the Versabar “Bottom Feeder” custom salvage system. The connection has a rated thrust capacity of 2,500 tons and a range of motion of +/- 25 degrees. The detail consists of a main pin of 38 inches in diameter and a minor pin of 18 inches in diameter. Lubricated bronze bushing inserts may be used on the wear surfaces as required. Readily available and Industry standard materials can be used for joints with contact stresses in the range of 5 to 10 ksi. Plate 4 shows the Custom Salvage System in operation, with two of these articulating joints incorporated into the system.
Even given the understanding of material wear predictions under cyclic loading (Archard Equation) an additional safeguard for the articulating connection is proposed in the form of a redundant outer Articulating Joint. Using this arrangement each primary connection can be removed and replaced on an as-needed basis during standard operating conditions.

Articulating Joint
Simple Two Degree-of-Freedom (left) & Redundant Joint (right)

Fabrication of Pin-in-Pin Articulating Joint

Custom Salvage System
VERSABAR’s 4000t Salvage System using pin-in-pin articulated joint brings a 1200t production platform to the surface in June 07