4 BLADE PROPS VERSUS 3 BLADE STANDARDS

[jackson]

HI GUYS MY SECOND MATE AND I HAVE A KOSICAT 16 CENTRE CONSOL WITH 2X 50 HP YAMAHA'S ON THE BLUNT END. A FEW GUYS HAVE SAID WE SHOULD CHANGE THE PROP'S TO 4 BLADE STAINLESS STEEL WHICH WILL CUT THE FUEL CONSUMPTION BY ALMOST A THIRD? AT R4500,00 A PIECE IT SEEMS AN AWFULL LOT OF MONEY WITH NO DATA ON HAND.

WE PRESENTLY SPEND ABOUT R360.00 PER 5 HOUR TRIP LAUNCHING OUT OF DURBAN HARBOUR ANY BODY OUT THERE WITH ADVICE,PAST EXPERIENCE OR CONTACTS FOR PROPS?

 

[Fin-S]

That claim seems to be a bit unrealistic. The 4 blades appear to be better at minimising cavitation and getting maximum grip (less slip) out of the motor. The local expert to give you the best advice would be Bruce Williams at Offshore Marine in CPT. 021 7861007

 

[Hammertime]

First off I'd give my left sack for a R360.00 trip, but that would be limited to where I am running to. That's 36l and in my case that would be 18.9 nautical miles. On my rig over 3 years I am consistently 1.85 - 1.95 liters per nautical mile.

First off you need to work out your fuel usage for a Liter to a Nautical Mile, as that will tell us how economical you are or aren't in relation to other boaters. Guess what I am saying is what distance are you traveling on your 36l.

4 blades on the lower size motors are VERY SELDOM the solution.
Please give Bruce a ring before you buy 4 bladed props, and tell us what your liter per Nmile is.

Ciao
Hammertime

 

[jackson]

took me ages to work out,but here goes,36 litres/21nm that i think is 1.7litres/nm,most of the milage is done racing from from durban harbour up to umgeni mouth,then plus minus 4 hours of slow speed trawling for natal snoek( maybe 8nm tops),then out to sea for 3nm to fish at number one(high speed),thereafter fast ride back to duran bay +/-4nm.your thoughts?

 

[Hammertime]

I must be honest, I don't think that is bad for a 16ft boat with 2 50's on. These are 2 Strokes right. It's by no means thirsty.

On four stokes you'd drop to 1.4l to a max on 1.2l.

I would def give Bruce a call as you could come down to about 1.5 or so. Ask yourself if the 8jocks is worth 0.2l per mile too.

Hammertime