I've been thinking along the same lines these past few days. Thanks for sharing this interesting bit of naval history.

FW and Anne couldn't marry because he had no fortune and no solid means of supporting a wife. Anne's father had "a professed resolution of dong nothing for his daughter" so I take that to mean she wasn't to receive any monetary support from her family. The only option available to them was a prolonged engagement that might last many years before FW might see enough battle action and command enough prize money to make enough money to wed. He had to do it all himself, as he had no connections to help him rise in the ranks or be given command of ships that would have a chance of being in the right place at the right time. And all that assumes he wasn't maimed or killed at sea.

The other thing that strikes me in the story is that Anne and FW have had something of a whirlwind courtship. They have only known each other for under 6 months when FW proposes. He would be the first man she has ever been courted by and I doubt in her small part of the world she would have had much previous exposure to men. There is no mention of a season in London or any other opportunities that Anne would have had to compare FW with other men of her acquaintance. I particularly like the line, "Half the sum of attraction, on either side, might have been enough, for he had nothing to do, and she had hardly anybody to love..."