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27 September 2024, 15:03
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#1
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Member
Country: USA
Join Date: Sep 2024
Posts: 3
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Just bought a SIB
Hello first post here I just bought a FB365 and was wondering when I put an outboard on it is there any specific pitch it needs to be set to. Any advice is appreciated
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27 September 2024, 15:12
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#2
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Member
Country: UK - England
Boat name: Redneck
Make: Excel
Length: 3m +
Engine: 20 efi & 9.8 2s
Join Date: Jul 2020
Posts: 3,400
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Hi and welcome.
When you say "specific pitch" are you referring to the pitch of the prop or the outboard trim pin hole?
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27 September 2024, 15:36
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#3
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Member
Country: USA
Join Date: Sep 2024
Posts: 3
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Quote:
Originally Posted by Steve509926
Hi and welcome.
When you say "specific pitch" are you referring to the pitch of the prop or the outboard trim pin hole?
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The pitch of the prop
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27 September 2024, 15:55
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#4
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Member
Country: UK - England
Town: Colchester
Length: 5m +
Join Date: Sep 2016
Posts: 3,062
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Quote:
Originally Posted by CrimsunFalcon
The pitch of the prop
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Are you sure you mean that. A prop pitch relates to how far it moves forward for one rotation of the prop
Are you sure you dont mean the angle the outboard leg is at front to back. Which is in effect which hole the pin is in
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27 September 2024, 16:05
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#5
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Member
Country: USA
Join Date: Sep 2024
Posts: 3
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No I meant the prop pitch because its 12 ft if its not set right I dont think the boat will move right? I have no idea first boat I have ever owned
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27 September 2024, 16:15
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#6
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Member
Country: UK - England
Town: Colchester
Length: 5m +
Join Date: Sep 2016
Posts: 3,062
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Quote:
Originally Posted by CrimsunFalcon
No I meant the prop pitch because its 12 ft if its not set right I dont think the boat will move right? I have no idea first boat I have ever owned
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There is a lot more to it than that. What is the outboard you have/are putting on the boat
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27 September 2024, 16:20
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#7
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Member
Country: USA
Town: NorCal
Boat name: SHARKY
Make: AB
Length: 4m +
Engine: Honda BF75 & BF5
Join Date: Dec 2009
Posts: 2,074
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Welcome to the board
First you need an engine, then add the load of gear and people, and using a tachometer you have to purchase and install, take it for a run and see what max RPM is. This will help determine which prop. If buying a new engine and they are offering an upfront prop switch, I'd recommend asking the seller for advice, as they may be highly knowledgeable.
Engine trim, which is the angle of the outboard, is just as important. Usually around the second hole works to start.
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27 September 2024, 16:26
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#8
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Member
Country: UK - England
Boat name: Redneck
Make: Excel
Length: 3m +
Engine: 20 efi & 9.8 2s
Join Date: Jul 2020
Posts: 3,400
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To find out if you need to to pitch your prop up or down, you need to find out what the rpm of your outboard is running at , at wide open throttle. Compare that rpm with the manufacturers operating rpm, then you will know if you need to change the pitch.
If you use the search function on the forum and type in "pitch" a multitude of threads will give you all the information.
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27 September 2024, 20:08
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#9
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RIBnet admin team
Country: UK - England
Town: Cambridgeshire
Boat name: Nimrod II
Make: Aerotec 380
Length: 3m +
Engine: Yam 15 Tohatsu 9.8
Join Date: Nov 2007
Posts: 8,850
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You mention a 12ft pitch and I guess you might mean 12 inches? An outboard supplied with a 12” prop would usually be a 20 or 25hp. In any case it is rare for a 3.65m SIB to need greater than a 10” prop unless very lightly loaded.
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27 September 2024, 20:29
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#10
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Member
Country: UK - England
Town: Colchester
Length: 5m +
Join Date: Sep 2016
Posts: 3,062
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Quote:
Originally Posted by Fenlander
You mention a 12ft pitch and I guess you might mean 12 inches? An outboard supplied with a 12” prop would usually be a 20 or 25hp. In any case it is rare for a 3.65m SIB to need greater than a 10” prop unless very lightly loaded.
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I think he might mean a 12ft long boat, but perhaps not
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27 September 2024, 20:40
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#11
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Member
Country: UK - England
Boat name: Redneck
Make: Excel
Length: 3m +
Engine: 20 efi & 9.8 2s
Join Date: Jul 2020
Posts: 3,400
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Hi CrimsunFalcon, think it may be a good idea to start again and tell us all what you have, sib & outboard, what prop you already have on the ob, and what your likely load will be. I think once you have a bit more of a starting point, we may be in a better position to help.
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27 September 2024, 21:37
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#12
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RIBnet admin team
Country: UK - England
Town: Cambridgeshire
Boat name: Nimrod II
Make: Aerotec 380
Length: 3m +
Engine: Yam 15 Tohatsu 9.8
Join Date: Nov 2007
Posts: 8,850
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>>he might mean a 12ft long boat
Ahh yes.
I'm with Steve re post 11.
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28 September 2024, 05:38
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#13
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Member
Country: UK - England
Town: Colchester
Length: 5m +
Join Date: Sep 2016
Posts: 3,062
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Quote:
Originally Posted by Steve509926
Hi CrimsunFalcon, think it may be a good idea to start again and tell us all what you have, sib & outboard, what prop you already have on the ob, and what your likely load will be. I think once you have a bit more of a starting point, we may be in a better position to help.
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Indeed
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28 September 2024, 07:15
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#14
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Member
Country: UK - England
Town: Retford
Boat name: Spy-sea-one
Make: Excel 435
Length: 4m +
Engine: Suzuki Outboard/25/4
Join Date: Oct 2011
Posts: 7,518
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Quote:
Originally Posted by CrimsunFalcon
Hello first post here I just bought a FB365 and was wondering when I put an outboard on it is there any specific pitch it needs to be set to. Any advice is appreciated
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When I had my mercury 365 I put a 25 Suzuki on it with standard 11 inch pitch prop I found a pitch up or down works with the 10 inch more responsive in rough water speed wise depending on loading 2 knots difference between pitches my trim is set at second hole out permanently
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29 September 2024, 18:53
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#15
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Member
Country: UK - England
Town: Marple
Make: Zodiac
Length: under 3m
Engine: Tohatsu 9.8
Join Date: Jun 2009
Posts: 651
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l fear the O/P may have come, and gone.
l did similar tests when l got my SIB.
My Tohatsu 9.8 came with an 8.5 pitch prop. At WOT the RPM was 5,500.
Right in the middle of the manufacturer's recommendation of 5-6,000rpm
l tried a 9.5 prop and WOT was 5,000 rpm.
The actual speed of the boat was the same, although it took longer to get on the plane.
Trolling on the canal was a bit nicer l assume because the engine was working a bit harder at idle speed and was smoother.
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