ok... on the real ship, centre prop was 4 blade with a 3 blade either side, I've downloaded the picture of the graupner model and zoomed in and its got 3, 3 bladed props with the middle prop turning in the wrong direction. But really, who cares, you don't see the props when it's in the water, unless it's sinking bow first, in which case, surely you have more to worry about.