add-on wings
My '87 38' was built with the 4'11" shoal keel, and all documentation states that as the draft. However, it has wings that the dealer in Noank, CT, installed on several boats before delivery by bolting a large casting onto the bottom edge of the keel. It increased the draft to about 5'6", but this increase didn't appear to be reflected on any of those boats' documents when we were shopping for ours.
The add-on weighs about 900#, so it made the boat much stiffer. Several years ago I bought line drawings from BKYD, and the keel drawings appear to include this added-on wing so I'm guessing that the design came from that office.