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starcrafttom



Joined: 07 Nov 2003
Posts: 7878
City/Region: marysville
State or Province: WA
C-Dory Year: 1984
C-Dory Model: 27 Cruiser
Vessel Name: to be decided later
Photos: Susan E
PostPosted: Mon Jan 26, 2009 9:27 pm    Post subject: Reply with quote

yeah when honda built the new motor it came out to 105 to 110 hp, depending on who you asked or what sales rep you talked to. So honda not wanting to market a underpowered 115ph or a new rateing of 110 decided to go with a marketing the strongest 90 hp motor. So in boat test their motor looks better. I think its a great plan and a great motor. Starts everytime and no longer cold blooded like mine. lighter weight and more power, what not to love.
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Wefings
Dealer


Joined: 29 Nov 2005
Posts: 2086
City/Region: Panhandle
State or Province: FL
Photos: Cruise Ship #4
PostPosted: Tue Jan 27, 2009 4:06 am    Post subject: Reply with quote

Motor H.P. can be rated at plus or minus 10% The RPMs used to rate them may not be their top RPM .Case in point EFI Honda 90 redlines at around 61-62 hundred revs. At that speed it is a little over 100 H.P. at 5800 its putting out about 90.They are the most powerful at just under the rev limiter . All in all the Honda EFI 90 is pretty darn spunky!
Marc

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colobear



Joined: 23 Jan 2005
Posts: 2154
City/Region: Denver
State or Province: CO
C-Dory Year: 2006
C-Dory Model: 22 Cruiser
Photos: C-Cakes
PostPosted: Sat Feb 28, 2009 11:55 am    Post subject: Reply with quote

In the never ending quest for the perfect propellers I am again thinking about switching from 3 blade to four blade props on the twin Honda 40s. At the Seattle boat show a prop vendor suggested that by doing so I could run at the same cruising speed (12-16kts) but at a lower RPM. It seems that prop selection, at least for my power level and moderate cruise speeds, can yield only minor changes, but, always hopeful, I'm looking for better cruise economy and less engine wear. Any ideas? Thanks.
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eNORMous



Joined: 08 Jul 2008
Posts: 348
City/Region: Beaufort
State or Province: NC
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: Antibody
Photos: Antibody
PostPosted: Sat Feb 28, 2009 8:46 pm    Post subject: Reply with quote

IMO, for the size vessel I own (25' Cruiser) going from a 3-blade to 4-blade fixed-pitch propellor doesn't justify the cost for long range cruising. I might consider the adavantages if I were looking to gain a better hole-shot (possibly); since, understanding the variable involved in skulling would mean I'm really looking to gain substantial benefit - and, I just won't find any and I doubt I'd find much in long-range cruising.

I've a private pilot fixed-wing single engine rated license (since 1974). A bud of mine replaced his 3-blade props w/ 4-blade props on a new Moony he bought 5 years ago. He obtained a definite improvement in stall speed, maneuverability, and controllability in take-offs/landings - not much in long-range fuel economy (if any). Automatic adjusting CPP blades perform the best for realizing gains in fuel efficiency since they self-tune their pitch - but, you're way up the ladder in terms of aircraft size & cost - the same holds true for marine vessels, as well.

I just don't find there to be much of a gain realized at this size of vessel.

m2cw

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nieking



Joined: 01 Sep 2008
Posts: 18
City/Region: Lakeside
State or Province: CA
C-Dory Year: 2005
C-Dory Model: 22 Cruiser
Vessel Name: Miss Emily
Photos: Miss Emily
PostPosted: Fri Mar 25, 2011 1:32 pm    Post subject: Revisiting the prop question...F75 4-stroke Reply with quote

I know this an older post and it is a subject that has been beaten to death, but I thought I might update it with my experience with prop selection over the past few years.

I have a 22 cruiser with an F75 and its factory/dealer prop was a 3x13.25x17, which is sluggish on takeoff and I keep it as an emergency backup to my backup prop.

For general boating (fishing, sight seeing, dive runs, Catalina runs) I use an aluminum 3x13.5x15, which came from the previous owner and it works great when fully loaded (fuel, peps, gear, etc), or running light...thank's Don.

I also use Miss Emily for occasional shallow survey work (sidescan sonar) and for this activity I prefer the comprop plastic 4x13.5x15 because it gives me improved maneuverability at the 3-5 kts surveys speeds. Also, the props are cheap and when they bump rocks, or other hard features, they do what you want a prop to do, which is absorb the shock. These props are a disposable asset for this type of work (IMO), but I don't think they perform as well as the 3- blade aluminum (or stainless) for loaded long hauls.

-Just my two cents-
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breausaw



Joined: 18 Jan 2006
Posts: 1222
City/Region: Anchorage
State or Province: AK
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: Triple J
Photos: Triple J
PostPosted: Tue Apr 12, 2011 5:00 pm    Post subject: Reply with quote

Seemed like a good place to post this:

Results for Stainless Quicksilver Silverado 3 blade 13 3/8 R 14 pitch prop on carbonated Honda 90; same trip calm water.
I almost turned around 2 minutes out of Whittier because I could tell right away this prop wasn’t going to work, but the crew said no-way. I waited tell we reached our night anchorage before pulling down the dink and changing out the prop, took like 10 minutes.

Quicksilver-Not good! It was like driving a car with a 4 speed stuck in 3rd gear.
4200 rpm – 12 mph
4800 rpm – 15 mph
5500 rpm – 20 mph
6000 rpm – 22.5 mph (WOT)

Same trip putting back on my stock 3 blade 15 pitch prop.
4200 rpm – 17.5 mph
4800 rpm – 20 mph
5200 rpm – 25 mph
5500 rpm – 27.5 mph (WOT)

Granted I can’t achieve 6000 rpm with the old prop but way better performance at lower RPM. During sea trials with wife and child and a half tank of gas I was able to make 34 mph at 5850 rpm.

At this point I don’t think there is a better all around prop then stock aluminum 3 blade that came with the boat.

Stainless Quicksilver goes back to WM for store credit.

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2007 22ft C-Dory Triple J 2007-2012
2007 25ft C-Dory Triple J 2012-2018
Boatless for now but looking
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starcrafttom



Joined: 07 Nov 2003
Posts: 7878
City/Region: marysville
State or Province: WA
C-Dory Year: 1984
C-Dory Model: 27 Cruiser
Vessel Name: to be decided later
Photos: Susan E
PostPosted: Tue Apr 12, 2011 5:44 pm    Post subject: Reply with quote

wow, big difference. especially between 4850 and 5200 rpm, where you will run the most. with your stock prop how is your fuel burn?
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thataway



Joined: 02 Nov 2003
Posts: 20778
City/Region: Pensacola
State or Province: FL
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: thataway
Photos: Thataway
PostPosted: Tue Apr 12, 2011 6:04 pm    Post subject: Reply with quote

Certainly interesting--I wonder if for some reason the SS prop was mis labled? I don't know the blade area and diameter of the stock prop. The aluminum should flex some. Of course there are lots of differences between props--cup, rake, etc. The best way to check out props is to work with someone who will allow you to try different props. Folks like "prop gods" usually will get the prop right, but not they will exchange until you do. I have run many of my boats with stock props--and they work great--others need a custom prop. My Caracal was used, and came with what is thought to be the best prop--but its numbers are not what I expect....similar to your SS.
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Thataway
Thataway (Ex Seaweed) 2007 25 C Dory May 2018 to Oct. 2021
Thisaway 2006 22' CDory November 2011 to May 2018
Caracal 18 140 Suzuki 2007 to present
Thataway TomCat 255 150 Suzukis June 2006 thru August 2011
C Pelican; 1992, 22 Cruiser, 2002 thru 2006
Frequent Sea; 2003 C D 25, 2007 thru 2009
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breausaw



Joined: 18 Jan 2006
Posts: 1222
City/Region: Anchorage
State or Province: AK
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: Triple J
Photos: Triple J
PostPosted: Tue Apr 12, 2011 6:35 pm    Post subject: Reply with quote

starcrafttom wrote:
wow, big difference. especially between 4850 and 5200 rpm, where you will run the most. with your stock prop how is your fuel burn?


My overall MPG is about 3.3 to 3.5 for a typical weekend. Don’t have a flow meter just fill up the boat after each trip and divide into GPS mileage.. I usually cruise at 20 mph but push it up to 25 on returning to port the last 10 or 15 miles-sure that doesn’t help with fuel economy. We just never have the time or patience for relaxed cruising on 2 or 3 day weekends, perhaps someday.
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tpbrady



Joined: 08 Feb 2005
Posts: 891
City/Region: Anchorage
State or Province: AK
C-Dory Year: 2005
C-Dory Model: 25 Cruiser
Vessel Name: Bidarka II
Photos: Bidarka
PostPosted: Tue Apr 12, 2011 6:49 pm    Post subject: Reply with quote

Jay,

On the fuel injected 90 I found the Quicksilver 14 pitch to be the best all round prop and was able to get 31 mph plus with a heavy boat and good fuel economy on the low end. It almost sounds like the prop was cavitating. Are you running a Permatrim?

Last week end I ran a 4 blade Solas 15 pitch stainless on my Yamaha 150. I noticed a little more vibration with it, but it did perform well with a WOT speed that hit 35 mph just when the boat started porpoising. Fuel economy was slightly better than the 4 blade aluminum Solas in the same pitch. Fuel economy went up with speed. In other words 24 mph was better than 20 and 30 was better than 24. It peaked at 2.9 mpg at 30 mph. Just can't find any water to go that fast very often.

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22 Cruiser Bidarka 2004-2009
25 Cruiser Bidarka II 2010-2013
38 Trawler Mia Terra 2012-2015
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Tom on Icarus



Joined: 15 Sep 2007
Posts: 175
City/Region: Campbell River, Vancouver Island
State or Province: BC
C-Dory Year: 2008
C-Dory Model: 25 Cruiser
Vessel Name: Tranquil~C
Photos: Tranquil~C
PostPosted: Wed Apr 13, 2011 1:37 pm    Post subject: Reply with quote

Earlier in this thread Marc from Wefings wrote……
“……There is no new mousetrap in the world of props and the available ones are there for a reason . Get one to turn [with a load] fairly close to where your motor's RPM range should be and you have a winner .”

I have recently tried, what is generally reported here to be, the optimum prop for the boat. It is a 3X13.5X15 on my BF75 Honda pushing a 22 Cruiser with a medium load and, so far, I really like the increased speed at lower RPM compared to what I have been running (4X13X14). I think it must be giving me better MPG’s as well.
Honda Marine’s Propeller Test Report also recommends the 3X13.5X15 for the BF75/22Cruiser combo. Their tests return a W.O.T. of 5500 R.P.M. which is right in the middle of where W.O.T. should be for this motor (5000-6000).

My question to Marc and the Brats in general is this…My W.O.T. results are just barely 5000 R.P.M. (that’s “fairly close”). Is this acceptable given that it just makes the minimum W.O.T. or should I have it re-pitched to 14 to allow for the heavier loads? If I were to re-pitch, what do you folks think the end result will be?
As a footnote…I also have tried a 4X13X15 and it gave me barely 5100 or 5200 RPM at WOT so I had it re-pitched to 14 and it now delivers 5500 RPM at WOT but my cruise speed is really reduced (15 NMPH at 4800 RPM).

Thanks, Cheers, Beer
Tom
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NORO LIM



Joined: 24 Apr 2008
Posts: 875
City/Region: Olympia
State or Province: WA
C-Dory Year: 2006
C-Dory Model: 23 Venture
Vessel Name: NORO LIM (sold 12/12/14)
Photos: NORO LIM
PostPosted: Wed Apr 13, 2011 5:18 pm    Post subject: Reply with quote

Tom on Icarus wrote:

.
.
.
Their tests return a W.O.T. of 5500 R.P.M. which is right in the middle of where W.O.T. should be for this motor (5000-6000).

My question to Marc and the Brats in general is this…My W.O.T. results are just barely 5000 R.P.M. (that’s “fairly close”). Is this acceptable given that it just makes the minimum W.O.T. or should I have it re-pitched to 14 to allow for the heavier loads? If I were to re-pitch, what do you folks think the end result will be?
Thanks, Cheers, Beer
Tom


I'm no expert and I have a different hull (Venture 23) and different engines (twin Yamaha 50's), but I've been told you should shoot for the upper half of the WOT range with whatever you consider a normal load. I do some long-range cruising with a very heavy load and recently went to a lower pitch to achieve that goal. I'm quite happy with the results. It does mean, however, that WOT with a light load now can hit the WOT max of 6K if conditions are just right. Of course I don't run like that very often - mostly just out of curiousity once in a while.

Predictably, I'm turning the new props a little faster than the old ones at any given speed, but performance and mileage appear to be at least as good as before.

Honda guys may know better about optimum WOT targets for your motor.

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