bettcha never heard of "Navigating with potatoes?"

Maine radar

I once wrote a poem based on a true incident with this idea in it.

In a dungeon of thick fog, we were crawling along in Penobscot Bay Maine, and my mate was worried that we would plow into the side of one of the hugh tankers out there, so, I told him we would have to navigate with potatoes. He was to stand on the bow, and one by one, throw a potato straight ahead as hard as he could.
If one of them didn't splash, I would come about...