A lot of the detail is going to be a 'best guess'. Which is a pity, because once I get to see the original oil on canvas painting; I will see my errors and will have to consider repainting the whole blinking thing. So a better solution would be to source a nice crisp image showing all of the detail, now!
Especially a clear shot of the boat beyond the main one. I've trawled the Internet and checked out a few books. Maybe I will end up in the National Library to see if they have a large print reproduction of the original inside one of their holdings.
Another approach would be to continue as far as I can. Then stop and store the work. Visit the Tate, do some sketching and then return to complete my inferior copy. The main problem with that approach, is that it means longing it out. And I don't like longing anything out, which is probably why I give oil painting a miss.