Hi Sigrid. Please take MORE pictures, especially of the rest of the boat/hull, as the deck spilts could be dealt with in several ways. One of our chaps does this sort of thing (yachts) more often than the rest of us not so much, but some basic principles still apply.
What sort of finish would you be wanting, keep it original or nor bothered too much?
is the hull wooden or fibreglass?
Ashley