Re: 4 blade and 3 blade propellers
Propeller theory is fascinating.
I had a great introduction to the realities of pitch compromise when I was a kid going for rides in my uncle's boat. At the time, though, I didn't understand what I was experiening or what the issues were.
It was a late sixties-era Humber Jewel with a 65 Merc on the back. A very small boat (can't remember exactly but probably about 12 feet LOA) and the big old 65 was a good 20 hp over the max rating for the boat. At rest it floated with the snout way up in the air. Actually, I'm amazed my parents let me go anywhere near it or my uncle.
Anyway, it had this funky two blade bronze or brass racing prop and it would struggle mightily with that setup to get on plane. You had to stand on the seat and lean over the windshield while the motor roared and you went nowhere...at first.
Once that bow finally came down however, and you were firmly on the plane, the whiplash acceleration was incredible all the way to the top end - which was damn scary in that little thing.
My uncle didn't know squat about pitch issues either and I remember him trying to get a skier up on two boards once with that prop and it just wouldn't do it no matter how much he thrashed that thing up and down the lake. I would love to know what the pitch of that prop was.
