4 blade propellers

DJL · 25 October 2007, 12:20

Does anyone on here have experience of 4 blade props on RIBs?

I'm currently running a 21" standard Yamaha black steel 3 blade on my Yam F150. WOT is ~5300 @ 42kts.

I'm after better grip, especially in rough water.

I'm thinking of a SS 19" 4 blade - should give me another ~200 RPM.

Bigmuz7 · 25 October 2007, 12:24

I changed from a stainless 21" 3 blade to a stainless 21" 4 My RPM went down slightly top speed was the same, but grip improved in turns, and in rough, but not for hole shot

DJL · 25 October 2007, 12:34

Quote:

Originally Posted by Bigmuz7

I changed from a stainless 21" 3 blade to a stainless 21" 4 My RPM went down slightly top speed was the same, but grip improved in turns, and in rough, but not for hole shot

Intresting - I thought hole shot would improve, although you stayed at the same pitch which might explain it.

Cookee · 26 October 2007, 13:54

More blades generally mean fewer revs, as does an increase in Diameter, so it might actually slow you down - how high is the engine on the transom? It might help if you lower the engine by one bolt hole. Also take a good look at the prop, a slight nick in a blade can also cause this - it might help to send it away for a tune up and balancing if it has had a hard life!