I have 3 different props to test and Im going to find it tough to launch/retrieve/launch /retrieve etc etc to swap the props out and test due to the fact that Ill probably have to park half a mile away from the boat ramp while testing.
Im thinking about pulling up to the jetty, tilting the motors up and swapping the props.
Im worried about easily removing the split pins and dropping them.
Can I use something else thats going to be easier to remove and replace while hanging out over the water.?
Changing props on the water is a challenge, dropping stuff is common, is there some kind of calm beach/shore you can go to and just get out and do it? The split pins are no issue, but, you drop the nut, one of the washers or the prop, then you have dramas! Technically you could test without the split pins, as long as the nut is on, or even use cheap steel split pins for testing and take a few of them.
Stand up paddleboard tied across the back of your boat under the outboards while they’re trimmed up has worked for me in the past
Buy a nylock nut for testing, then once you fit the selected prop change back to the castle nut and split pin.
Do not rely on the castle nut without the pin....they can come loose and you will drop the prop when you back off or hit reverse.
Jack.
This is a good idea if you can find a calm beach...wonder if a length of wire and pliers or sidecutters would be easier then ####ing around with fiddly split pins in that situation as well..Originally Posted by Noelm
sounds a bit painful as you have 2 motors to deal with right..?
What a great idea.
Shawn
You can tie a bucket under the skeg so you catch anything you drop.
Thanks Nolem<
i pulled up to a sand bank and did things really carefully. Swapped out the 4mm split pins with 2.5mm pins meaning no tools to remove and replace.
Yeah I had to work fast with the incoming tide. Used thinner and longer split pins.
Thats a great idea. Cheers
I ended up undertaking a successful prop swap. Yippee.
Im a little disappointed with the results though.
I was really excited to test the SS 4 blade 17 inch Pitch props
They still dont move as fast as the 3 blade aluminium props that came with the boat>
Im not sure which way to move next and still waiting on some direction from the supplier.
One thing on the positive side is the 4 Bladers are way smoother and give more grip during turns but what I am chasing is more km/l
It has been suggested I try a 16 inch 4 blade but I cant see that making any difference>
I want to run between 4000 and 5000 rpm and I cant see how a prop with smaller pitch can propel the boat forward further with each RPM>
here are the numbers, what do you think?
4 blade 13.25
17P SS HR Titan
RPMSpeed kph Speed Knots Fuel
km/l3 Blade Suzuki OEM 13.875
15PSpeed Kph Speed knots Fuel Km/L 4350 37 20 1.7 4300 39 21 1.8 4500 40 22 1.65 4500 43 23 1.8 4700 41 22 1.5 4700 47 25.5 1.8 4900 44 24 1.46 4900 48 25.5 1.6 5500 WOT 53 28.5 1.1 5300 52 28.5 1.2 5800
WOT56 30.5 1.2
Based on those figures stick with the 3 blade. The 4 blade is designed to give you hole shot, ie get you up on the plane quicker.
One of the sad signs of our times is that we have demonized those who produce, subsidized those who refuse to produce and canonized those who complain.
Thomas Sowell
I'm with Sam...never hurts to test some more but I'd be pretty happy with 1.8km/l on a 6m reef boats with twins...sure beats my best of 1.5 but average closer to 1.3km/l...
Why did you jump 2" in pitch with another blade?
The more surface area you have the more you load the motor....same with pitch.
You might have been better off with 16" pitch 4 blade if you really wanted to go down the 4 blade route.
The other option is 3 blade 16" pitch or same pitch and larger diameter (the latter worked best on my boat increasing 1/2" diameter for 8kph increase).
Jack.
It’s not just about how far forward it moves you through a revolution
engine loading engine fuel economy sweet spots are all considerations when chasing fuel economy
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