They had just completed their second and last dive of the day and were back aboard when he showed up at the trace line float. 2 divers were still down on the wreck and weren't due back for another 10 minutes. The dive boat captain elected to drop a spear gun and message slate down the anchor line in the hopes that they would come up armed when their dive concluded. Fortunately, the big fella decided to checkout the other diveboat (tied up at the other end of the wreck); he was gone just long enough for the divers to surface & re-board the boat. Frankly, I think the spear gun would have just p*ssed him off!
My friends got some good video of the shark passing close along side the dive boat. When they got home, my buddy immediately went out and purchased a 44-mag "bang stick."