14.25x21 Aluminum to 15.25x19 Stainless
06-27-2017 | 12:09 PM
#1
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From: Toronto, Ontario
14.25x21 Aluminum to 15.25x19 Stainless
Hey Guys,
What RPM difference will I notice changing diameter on the prop? I currently have a 14.25 aluminum 3 blade prop that turns about 4700 rpm and a 14.25x18 4 blade prop that turns 5000 rpm. A friend loaned me a mirage plus 15.25x19 stainless prop and I was wondering what I should expect out of it? The boat is a Larson Senza 206 with a 5.0L EFI Volvo Penta (270hp).
What RPM difference will I notice changing diameter on the prop? I currently have a 14.25 aluminum 3 blade prop that turns about 4700 rpm and a 14.25x18 4 blade prop that turns 5000 rpm. A friend loaned me a mirage plus 15.25x19 stainless prop and I was wondering what I should expect out of it? The boat is a Larson Senza 206 with a 5.0L EFI Volvo Penta (270hp).
06-27-2017 | 09:43 PM
#3
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Joined: Jan 2002
Posts: 4,612
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From: ALTO, MI
Just keep in mind that IF you boat in an area where you hit things from time to time. The stainless in less forgiving. The aluminum prop will bend easily - the stainless won't
I have bored right through a sand bar at idle with a stainless prop and all it did was bend the tips a little. With an aluminum prop you wouldn't have any blades.
Years ago with the SCARAB on occasion I would spend the night in the cove just inside the inlet at Saugatuck MI.
This time I pulled up to the beach late. I always drop a rear anchor and then tie up to the beach so the boat is always floating. When I pulled up there was an aluminum boat with a cabin about 25 ft long. He had parked sideways to the beach and there was only about a foot of water between his boat and the beach at midnight. In the morning I was sitting on the back of the boat having a cup of coffee when he came out of his cabin. After a few minutes of conversation I told him that when I was done with my coffee I would pull him off the beach - that he was stuck.
He then told me that he wasn't stuck ( there was no water between his boat and the beach now ) and proceeded to try to drive off the beach.
After about 2 minutes I asked him from the beach if he had an aluminum prop on the boat - he said yes.
I then told him to shut it down because he no longer had any blades on his prop and proceeded to wade into the hole he dug and pulled out all three blades.
And he didn't have a spare.
It took about half throttle to get him off the beach and then tow him into town to find a prop.
He turned out to be a nice guy and he learned a lesson that day.
I have bored right through a sand bar at idle with a stainless prop and all it did was bend the tips a little. With an aluminum prop you wouldn't have any blades.
Years ago with the SCARAB on occasion I would spend the night in the cove just inside the inlet at Saugatuck MI.
This time I pulled up to the beach late. I always drop a rear anchor and then tie up to the beach so the boat is always floating. When I pulled up there was an aluminum boat with a cabin about 25 ft long. He had parked sideways to the beach and there was only about a foot of water between his boat and the beach at midnight. In the morning I was sitting on the back of the boat having a cup of coffee when he came out of his cabin. After a few minutes of conversation I told him that when I was done with my coffee I would pull him off the beach - that he was stuck.
He then told me that he wasn't stuck ( there was no water between his boat and the beach now ) and proceeded to try to drive off the beach.
After about 2 minutes I asked him from the beach if he had an aluminum prop on the boat - he said yes.
I then told him to shut it down because he no longer had any blades on his prop and proceeded to wade into the hole he dug and pulled out all three blades.
And he didn't have a spare.
It took about half throttle to get him off the beach and then tow him into town to find a prop.
He turned out to be a nice guy and he learned a lesson that day.
