USAAF aircraft lost through transport sinkings during Battle of the Atlantic?

I've seen many photos of USAAF aircraft loaded on ships for transport to England. But I've never read how many aircraft (as cargo) were lost due to ships being sunk by U-Boats during transit. I seem to recall somewhere that when the P-51C introduced a dorsal fin, that fins were manufactured for retrofitting to in-service P-51B's -- but that the ship carrying all of these dorsal fins was sunk.

Are there any estimated or actual numbers, and perhaps by aircraft type? When I search, it seems like I just come up with aircraft lost operationally (not as cargo).

A few days ago I saw a bunch of post war PDFs that listed U.S. shipments but at the moment I can't recall how I entered the search and unfortunately I cleared my cookies and history about 20 minutes ago

Here is a list of everything(?) the U.S. shipped during the war. Still looking