The helicopter and boat chase scenes were not in the original novel but were added to create an action climax. The former was inspired by the crop-dusting scene in Alfred Hitchcock's "North by Northwest" and the latter by a previous Young/Broccoli/Maibaum collaboration, "The Red Beret". These two scenes would initially be shot in Istanbul but were moved to Scotland. The speedboats could not go fast enough due to the many waves in the sea, and a rented boat filled with cameras ended up sinking in the Bosphorus. A helicopter was also hard to obtain, and the special effects crew were nearly arrested trying to get one at a local airbase. The helicopter chase was filmed with a radio controlled miniature helicopter. The sounds of the boat chase were replaced in post-production since the boats were not loud enough, and the explosion, shot in Pinewood, got out of control, burning Walter Gotell's eyelids and seriously injuring three stuntmen.