Ship captain's log is a book and a quest item in the Blood and Wine expansion.
It can be found in the Blood and Wine expansion at the hidden treasure marker between Plegmund's Bridge and The Silver Salamander Inn, together with a key, starting the treasure hunt quest What Was This About Again?
Journal entry[]
[Journal is completely soaked, only a few entries can be deciphered]
Belhaven, 23rd Day of service
Nothing irritates me more than land rats thinking they're cock of the walk. Yet Count Jean-Joel Baillairgé – that's what the impertinent prick made me call him –managed to assuage my irritation a dab by clinking a hefty pouch of Nilfgaardian florens on the table... [illegible fragment] ...his entourage loaded the ship with bundles, then hauled on this huge cage covered with a sail. Count Baillairgé explained it held one of those famed Zanguebarian striped horses – a gift for Duchess Henrietta.
Belhaven to Beauclair Route, 24th Day of Service
We've had nothing but trouble with this Zanguebarian horse! It gnaws on the deck like a beast gone mad. Plus we've got to make sure the tarp covering its cage is tightly fastened, for it seems this creature's as sensitive to the sun's rays as a vampire! In which case, what good's it to the duchess, a striped horse she can only ride it at night? There's no comprehending these aristocrats... [illegible fragment]
Belhaven – Beauclair Route, 25th Day of Service
A thousand thundering sea devils! That was no horse in that cage, but a gods-blasted shaelmaar! Overgrown rock rat chewed through the deck, capsized the ship and burrowed into the river bottom! Then that idiot Count Baillairgé fell to his knees and begged me to help catch the monster. He handed me the key to the chest of jewels he'd kept close watch on the whole trip and swore it'd be mine if we recaptured that monstrosity. I'd most like to grab a thick club, smack him upside the head and take that chest right now, but I'm not some ploughing pirate. I'll gather the lads who managed to survive the wreck and we'll try to catch the monster in our nets – the count claimed to know some trickery to sneak up on the beast...