Yes Roy, there was a complete evolution in the design of rudders on vessels over the last Centuries
200 ton sailing vessels anchoring mid stream & using ships boats for transportation of cargo & loading
100,000 tonne passenger cruise vessels mooring directly to wharf's without the aid of tug boats
Without going to our Australian paddle ships with Barn Door rudders, sail barges from London waters from the late 1800's used substantial stern [external] rudders to sail.....moor & berth without external assistance
On of the cargos carries is listed with Coal, Barley, Timber, Wheat, Coke ........etc and Oil Cake...........was this another name for Peat?
Derek