Salut a toi Papy!
I'd rather have stock sinked little red icons on map (using NewUIs) than boats staying on ground!
...to keep tracks of my adventures when saving/reloading.
Never was able to, and NewUIs destroyed marks are always spawning way off the action, not to say when they are not working at all (even with boat's journal activated)
That belong to my SH5 wish list: ability of game to save and keep marks (ruler, protractor, destroyed icons etc) each time we save/reload.