More pics & close-ups coming soon, Stefan. (thing is I have to resize them all considerably before being able to post them on Playmofriends).
The canons below deck are indeed the "slide-in cannon-mouths" from the 5135-ship. Reason is it would be much too difficult to reach and displace standard Playmobil canons in the lowest deck.
Unfortunately the captain's cabin can't be opened up anymore, that is a downside but I can understand Leo made it like this, keeping in mind the ship's castle/stern is mainly made of 4290-cabins build (with glue and reinforcements) the one on top of the other. It would have been nice if it were accessable, but as the ship is not really intended for play it doesn't bother me that much. There is a stearman's house though, just behind the mizzen-mast, on the maindeck's level.
Meanwhile I've made some refinements, of which I will also post pics:
I've replaced both the anchors by big Playmobil ones from the Pirates' Ghost Ship, and the fat anchor-ropes with somewhat thinner ones. I've also switched the red canon-carriages on the upperdeck for brown ones, as imo brown fits better with gold-coloured canonbarrels. And on each side I've added a carronade on the officer's deck (for that I'm using the black wheelless canon-carriages). Further some addiotional details like 2 more lanterns on the stern, a ship's bell on the main mast, etc.