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18-11-2016, 08:42
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#16
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Registered User
Join Date: Dec 2008
Location: SC
Boat: None,build the one shown of glass, had many from 6' to 48'.
Posts: 10,208
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Re: 3GM30F, Morgan Out Island 28 Prop
Quote:
Originally Posted by jimbunyard
Just curious, what is the definition of 'efficiency' in this case? Is there a 'maximum', real world efficiency that can be achieved and/or expected?
10x7x3 seems tiny, I have a 12x10x3, with an MD2020 (18hp)...
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I believe efficiency is determined by how far you go forward for each revolution of your prop as a % of pitch under ideal conditions. Given the variable in hull configuration I doubt there is a % anyone can rely on. An educated guess and then trial and error. Planning or displacement? My guess if you can get 50% you are lucky. MHO
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18-11-2016, 09:16
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#17
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Registered User
Join Date: Dec 2008
Location: SC
Boat: None,build the one shown of glass, had many from 6' to 48'.
Posts: 10,208
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Re: 3GM30F, Morgan Out Island 28 Prop
Quote:
Originally Posted by DivinaVita
I need prop recommendations for a recently acquired 28 Morgan Out Island.
The basic specs are as follows:
74' Morgan Out Island 28 (LWL 23.83', Beam 9.25', Displacement: 7600 lbs); Repowered with Yanmar 3GM30F (Freshwater cooled), 27HP @ 3,600 rpm; Kanzaki KM3-A Gear, Ratio 2.62:1.
The current prop is a 10 X 7.4 X 3; however, the boat tops-out at approximately 2.5 knots; and, has little or no reverse thrust.
Any assistance would be greatly appreciated. Thanks in advance!
Rick
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Rick.
With all of the Out Islanders out there, there must be an owners group that can probably be helpful.
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18-11-2016, 12:25
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#18
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Registered User
Join Date: Oct 2016
Location: Alberta, canada
Boat: C&C 34+
Posts: 27
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Re: 3GM30F, Morgan Out Island 28 Prop
have the same engine / gear on a 36' 12,000# fin keel C&C, which originally came with a 16" 2 blade -poor performance & VIBRATION ,went to a 3 blade Michigan, sized by them for the engine, -over propped and lost 1/2 kt under sail, installed a 16" 3 blade Campbell sailor- better under sail , poor reverse- installed a 2 blade flexofold- more vibration- went to a 3 blade flexofold -finally the right prop- good under sail, forward and reverse although reverse requires high rpm.
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30-11-2016, 12:03
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#19
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Registered User
Join Date: Nov 2014
Boat: Hunter 40 Legend
Posts: 4
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Re: 3GM30F, Morgan Out Island 28 Prop
Good Day!
Thank you all for the information and advice. The boats current configuration allows for a 14" prop with the prescribed 10 - 20% prop/hull clearance. For testing purposes, last week, I purchased a 14" X 14" 3-blade Michigan Wheel prop. With that prop, at 2800 rpms, the boat reaches the calculated hull speed of 6.5 knots and exceeds 7 knots at WOT. Thank you all again for the information and advice; it is sincerely appreciated.
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30-11-2016, 12:47
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#20
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Registered User
Join Date: Aug 2006
Location: Skagit City, WA
Posts: 25,477
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Re: 3GM30F, Morgan Out Island 28 Prop
Thanks for the update, good to hear.
__________________
"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard
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30-11-2016, 12:50
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#21
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Registered User
Join Date: Dec 2008
Location: SC
Boat: None,build the one shown of glass, had many from 6' to 48'.
Posts: 10,208
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Re: 3GM30F, Morgan Out Island 28 Prop
Quote:
Originally Posted by DivinaVita
Good Day!
Thank you all for the information and advice. The boats current configuration allows for a 14" prop with the prescribed 10 - 20% prop/hull clearance. For testing purposes, last week, I purchased a 14" X 14" 3-blade Michigan Wheel prop. With that prop, at 2800 rpms, the boat reaches the calculated hull speed of 6.5 knots and exceeds 7 knots at WOT. Thank you all again for the information and advice; it is sincerely appreciated.
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Great!
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