The certificated commerical pilot, with 5 passengers aboard, was departing from a remote beach site. During the departure roll, just before takeoff, the airplane's right wing struck a truck-mounted gantry that was parked on the beach. The pilot continued the takeoff, and ultimately made a precautionary landing at another airport about 130 miles from the accident site. Postaccident inspection revealed about twelve inches of the right wing was severed during the accident.