NavList:

Robin, going back to your original message on this, you wrote:
"I visited the Royal Navy Submarine Museum in Portsmouth, England recently. In their collection they have a Frock Coat and Cocked hat that were owned by Admiral Sir Martin Nasmith."

I visited that museum in 2012. I was most impressed by the (recovered, formerly sunk) Holland 1. I had not realized until I visited the museum that there were any Holland boats left.

"Although the bicorne hat is only roughly triangular when seen side on ..."

I see what you're saying now. Some navigational "cocked hats" might metaphorically resemble a bicorne hat seen from the side. And some navigational "cocked hats" look like a tricorne hat seen from above. Yes, that's possible, but I would say there's just no way to prove it or disprove it. If, as seems likely, the term arose "from below" (from usage among practitioners who found it an amusing turn-of-phrase), then they would never have recorded an original sense. It would have originated in "oral tradition". And even if we could find a source in print, let's say in 1901, near the time when the expression seems to have originated, that states specifically that a navigational "cocked hat" looks like a bicorne hat side-on, it would only constitute that author's best guess at interpreting an oral tradition. Finally, since in later decades, continuing to the present, navigators have decided that the metaphor refers to a three-cornered hat, then that's the sense of the metaphor today, regardless of whatever some nameless surveyor/hydrographer five generations ago meant when he coined the phrase and started spreading it to his students.

/_\

^Look, I made a cocked hat ...a bit breezy at the top, but it's a hat! :)

Frank Reed