35 Duffy

trial

Member
Joined
Jul 16, 2012
Posts
29
Likes
10
Sure looks like the same boat. Came across it on yuckworld searching for 31's.
 

AL.M

Member
Joined
Feb 27, 2020
Posts
20
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7
Age
54
Interesting that the owner claims 16knt @ 2000rpm = 1gpm. The C9 burns 24gph at 2000rpm C9 is rated for 2500rpm with 26gph. Something does not add up
 

powderpro

Captain
Joined
Dec 3, 2011
Posts
3,386
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2,859
Location
The Ocean
Website
www.oneilboats.com
Boat Make
O'Neil
Interesting that the owner claims 16knt @ 2000rpm = 1gpm. The C9 burns 24gph at 2000rpm C9 is rated for 2500rpm with 26gph. Something does not add up
You are looking at the wrong fuel curve. For the 510hp C9, 2,000rpm is around 13 gph. If the engine is burning 16ph at 2,000rpm, it could indicate it's a little over propped. The ad also says wot is 2,400rpm, but the engine is a 2,500rpm engine, so that's another indication it could be a little over propped. You can't go by what an ad says because they usually have errors, so the boat may not be over propped. But based off those numbers, the first thing I would check is if the engine can hit rated rpm (2,500). Nice looking boat, can't beat a 35' Duffy.


Screenshot (77).png
 

Blitzen

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Sep 1, 2011
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2,909
Location
Sumday Isle, RI
Boat Make
Flowers Boat Works 46, 1991 Boston Whaler Outrage 19
Interesting that the owner claims 16knt @ 2000rpm = 1gpm. The C9 burns 24gph at 2000rpm C9 is rated for 2500rpm with 26gph. Something does not add up
Whoa you are way off. My C9 at 575HP prop demand was 28.5 GPH WOT and at 2000RPM was 16-18 gph.
 
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El Mar

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Joined
Sep 1, 2011
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2,726
Location
Westbrook, CT (The Asshole State)
Boat Make
43 Tiara Open DDEC, GradyWhite 268 Islander, 18 Donzi Classic, 15 Boston Whaler Sport ETec 60
Beautiful boat, for 200K you think they would wipe the mold off the inside.
 

southshore30

Senior Member
Joined
Feb 22, 2012
Posts
395
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190
Location
Cape Cod,MA
Boat Make
Calvin Beal/Southshore 30
Shouldn’t a 35 cruise faster than that with 510hp? 19knts? My friends with a 420 3126 does about that.
 
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