The Lampson had just finished picking up a 950 ton vessel (kind of pushing capacity) from the horizontal position to the vertical position, and began its trek to the left (backing up-traveling under load). The rig was traveling on mats which sat on top of a hogged out, compacted fill. As the counterweight section crossed onto one of the mats it shifted creating an immediate strain on the entire rig. The boom had no time to react and failed. The lattice work sounded like popcorn when it went.Fortunately the vessel landed upright on the crane mats. The 12″ drop did not hurt the vessel, but did feel like an earthquake. The vessel wobbled a little bit while everyone scattered. A very scary experience.Root cause: It was discovered that a recent rain storm washed away some of the base from under the crane mats providing a void which was exploited by the rig.
Category: Accident Report