Easy!
Jon, if you snapped the 29" line...it would have come right up out of the top of the cb trunk and be rather obvious. However, if it only pulled out of the cb (unlikely) but still had the knot, it would be pulled all the way up and the tackle used to lower the board would be 2-blocked ie: the blocks touching. If you broke the part running through the blocks, you will see that right away, since the whole works is right at the entrance to the cuddy.I forget, which line broke? The line to pull the board up, or the line to pull it down? The cable that is attached to the CB to pull it up could have come loose from the board, if so..the cable will be loose with no tension on it. If it broke inside the CB trunk, it would have pulled right out of the hole in the trunk and be laying in the cuddy. I have included a photo of what my cb lines look like with the board pulled most of the way up. If yours doesn't look like this, let me know.