AQ290 duoprop propellers

[Mistified]

I have a 32ft motor boat with Diesel engines 2 out drives . On checking boat when out of water I discovered props had different size fitted ?
port side - large 3 bladed and small 4 bladed

starboard side - same size 3 bladed as port side with a large 4 Bladed
I cannot see any marking on props can anyone advise what are correct size 4 blade prop

 

[sogood]

Is there any possibility that they are actually the same, as in matching, but just fitted opposite way around to maybe allow for drives rotating in opposite directions? Maybe I'm talking absolute rubbish, but I'm reminded of something I heard somewhere once. The props should have part numbers stamped on them on the hub section. Just a thought.

 

[RichardS]

Is there any possibility that they are actually the same, as in matching, but just fitted opposite way around to maybe allow for drives rotating in opposite directions? Maybe I'm talking absolute rubbish, but I'm reminded of something I heard somewhere once. The props should have part numbers stamped on them on the hub section. Just a thought.

They are double contra-rotating props. One each side is the same size but the other one is a different size although could be the same thrust if the pitch is different. It sounds rather odd but I've no idea why it might be like that.

Richard