[2020] can not equip ship itmes

I have been playing anno 1800 sinds end of december. Now i am able to equip items in a museum or the trade Union, but i can't get items to equip in ships. i drag them to the ship item slot but it won't stay there after dragging it there. What am i doing wrong.

Sometimes when i shoot other ships and i get for example a torpedo it immediately oputs it in the item slot but as soon as i get it out of there i am not able to put it there again.