Flexofold Prop

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wolfe10
Posts: 587
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Location: Ft Myers Florida

Re: Flexofold Prop

Post by wolfe10 »

Leigh,

What speed do you do at that 2,300/2,400 RPM cruise on flat water?
Brett Wolfe
C350 #180
"Vindaloo"
Ft Myers FL
leigh weiss
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Re: Flexofold Prop

Post by leigh weiss »

Brett,
As I recall with a clean bottom the GPS shows 6.5 Kn.
I can go to 7+ @ WOT. but not worth the extra fuel.
BTW...The sweet spot for the specific fuel consumption is about 2300 rpm. I found the graph for the same Tractor/industrial engine.
Leigh Weiss

Brisa #155
South Jersey
Leigh and Donna Weiss
Brisa #155
Georgetown, MD. USA
yodagwb
Posts: 117
Joined: Fri Jan 27, 2006 8:34 am

Re: Flexofold Prop

Post by yodagwb »

May I direct you to the following test done by Yachting Monthly out of the UK. Just that much more to consider. I had come across it prior to Flexofold adding a link, it was just easier to find via this link

http://www.flexofold.com/test-results/
lazy dog
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Re: Flexofold Prop

Post by lazy dog »

I recently asked Flex fold for a recommendation based on a M35B with the 1.88 reduction. They said to go with a 3 blade 15x9. In looking at posts from others it looks like they have previously recommended 15x10. Does anyone have experience with a Flex Fold 15x9 on a C350? Do those who have the 15x10 think it's the way to go?
wolfe10
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Re: Flexofold Prop

Post by wolfe10 »

Our 15X10 is over-proped. I would ask if they will allow you a one week "trial period" with the ability to change if it is not the correct prop.

As has been posted, determining whether it is the correct prop is NOT difficult.

With engine warmed up put the transmission in neutral. Just for an instant, go to WOT. Note tach reading.

Then with boat at at 5 knots or so on flat water, go to WOT. Note RPM as related to your tach reading under no load.

Ideal is at WOT in forward you are with 100-150 RPM of the no load RPM.

If the tach quickly went to no load RPM (governed RPM) the prop is too small.

If you are more than 200 RPM lower than no load RPM, the prop is too big.

Keep us posted.

Thanks.

Brett
Brett Wolfe
C350 #180
"Vindaloo"
Ft Myers FL
yodagwb
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Re: Flexofold Prop

Post by yodagwb »

I woud say that the 15/10 maybe a tad over proped. WOT I will max the rpms at 2900 instead of 3000. I feel it is the right prop for me due to the fact I am able to pick up additional speed at the lower rpms. Yes I can hit 7.5 knts + or- at WOT but the engine temp will start to rise. I do about 7mph at 2100-2200 rpms. I do 6mph at 1800-1900rpms and the engine temp is down around 165. I do like not having to push the engine hard not to mention the fuel saving and the quiter engine noise at the lower rpms. If you find yourself having to punch into a heavy chop often I would suggest you consider the 15/9 but the 15/10 is working well for My type of cruising. There I am sure that helped a lot. No closer to a correct answer then you were before. If you pick a pitch and its bad they will switch out the blades for a different pitch you pay the shipping.
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william vanwagoner
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Re: Flexofold Prop

Post by william vanwagoner »

Has anyone tried the 15x9 flexofold on their c350? I would like to know how it compares to the 15x10 which sounds like it might be a bit of an overprop. I have the m35b.

Thanks,
Bill VanWagoner #229
Bill VanWagoner
Destiny #229
wolfe10
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Re: Flexofold Prop

Post by wolfe10 »

Bill,

Good idea.

You might call Flexofold and ask them either for the name of someone or ask if they will contact them and ask that they contact you.

And, the relevant questions are:

What is your tach reading in neutral at WOT (for just an instant)? I put this one in here because there have been a number of tachs NOT reading accurately. The mechanically set governed RPM of the engine is a much more accurate number unless the tach has been calibrated

What is the RPM and boat speed in flat water at WOT?

Ideal is for RPM in gear at WOT to be around 100 RPM less than governed RPM.

Brett
Brett Wolfe
C350 #180
"Vindaloo"
Ft Myers FL
MorningStar

Re: Flexofold Prop

Post by MorningStar »

I’ve been in contact with Jack at Flexofold via email and telephone. He is recommending 15X10 prop.

With the Michigan 14X10 prop, my WOT no load is 3235 rpm and WOT cruising is 3135 rpm measured at the engine with a photo tachometer. My tach at the helm is low by about 125 rpm. My max speed in slack tide and flat water is 6.9kts. What this tells me is the engine is not loaded to rated horsepower (35hp) at rated rpm (3000). Based on other 350 owner experience with the Flexofold, I think the 15X10 slightly overloads the engine at WOT. But I want the max speed when needed as when passing a tow boat in the ICW. Thus would not operate the engine WOT for extended periods. Also when cruising with other boats I want to maintain 6kts or over to get to the next destination in due time. Sometimes I have a hard time maintaining 6kts with the engine alone consequently I motor sail where possible.

It appears that “350” owners that have the 15x10 Flexofold prop with the Universal 35hp engine are very satisfied. That also plays in my decision to purchase or not.

Thanks for all the input… still considering.

Barry Dupuy
s/v Morning Star #35
Kemah, TX
Carolina.Mind

Re: Flexofold Prop

Post by Carolina.Mind »

I have a 14" 3 blade prop from Catalina for sale if anyone is interested.
Prairie Gold
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Re: Flexofold Prop

Post by Prairie Gold »

I contacted Flexofold prop concerning a folding prop for my 350 and received the recommendation of 16x11. I am concerned this will be over propped given what I am reading on this site. I have hull # 495 with Yanmar 3YM30 and gear reduction of 1:2.62. Does anyone else have experience with this combination and flexofolds?
Phil Haydon
Boston, MA
s/v Prairie Gold
wolfe10
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Re: Flexofold Prop

Post by wolfe10 »

Prairie Gold,

Be sure you ONLY consider advice from those with the same engine and transmission ratio-- if is VERY different than the models with the:

Universal 35 HP M35B max RPM 3000.
Standard gear ratio from Westerbeke 1.79:1

Brett

ON EDIT: Of course, the other variable is number of blades. Was this for a 2 or 3 blade prop?
Last edited by wolfe10 on Mon Nov 09, 2015 10:48 am, edited 1 time in total.
Brett Wolfe
C350 #180
"Vindaloo"
Ft Myers FL
Prairie Gold
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Re: Flexofold Prop

Post by Prairie Gold »

Much appreciated Brett. I thought this was likely the case. Cheers Phil s/v Prairie Gold
Phil Haydon
Boston, MA
s/v Prairie Gold
Pgtjs
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Location: Blaine WA

Re: Flexofold Prop v. Kiwi Prop

Post by Pgtjs »

HI folks,

I have been watching the latest sequence of emails on Prop size and performance issues.

For those who have not yet purchased a Flexfold or Maxi Prop, I might draw your attention to a KIWI prop as a much cheaper option. Adjustment of the pitch in the water is easy with an Allen Screwdriver and a diver. I have had a 15" prop for 9 years with few problems and it is much cheaper to buy and maintain. Last year I adjusted (loosened) the pitch by a 1/4 turn which is about 1/2 degree as it was running a bit hot in the much warmer water prevalent last summer. It now runs all day at 6.5 knots and 180F and I can get 7.1 knots on max revs. The only maintenance is to grease it thoroughly - with a needle point and using marine grease - on every lift-out: otherwise it will baulk at swinging over to reverse the blades. In slow reverse it is easy to snuggle the stern sideways into a marina slip with a port side tie and folks are amazed at this capability.

Cheers, Geoff, TAEKO 1V, C350/#392, Semiahmoo WA.
Geoff.S., Semiahmoo, WA.
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