Propeller blues, need suggestions

[Galan “Rhett” Smith]

     There is an interesting story about my propeller.  The previous sale of the boat listed a three blade Maxprop. The engine had been replaced with a 2ygf and very nice dripless seal installed and the boat would have needed a new propeller.  When I bout the boat and we hauled it out there was a very used looking 2 blade Martec type folder. 

    I would appear that the prop and some instruments were sold in the two years that the next owners had the boat. Maybe the prop failed, who knows.  It would appear that I now have the original 1 cylinder propeller  and it vibrates like crazy.  Immediate repair required.

   Suggestions for replacement.  I have been told that you can rebushing a Martec but not change the pitch. Does any know the answer either way? 

    I searched prior convo's and will be  looking at availability of names mentioned. Any longer time reviews would be appreciated. 

   

[John’s Contraptions]

I have sitting on a shelf the original two blade Martec, nothing wrong with it other than it is for the 1GM10, no reasonable offer refused.  I replaced it with a FlexFold that works great (still 1GM10).  You probably need to go up in pitch with the extra HP.

While you have everything apart check your cutlass bearing for wear, the shaft straightness and engine alignment.  Of course the engine mounts tend to relax, throwing off the alignment.

 

John

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[dnewl...@msn.com]

I just got a bid on a Flexofold 2 blade for $1400.  Wow.  But it does seem to get high marks for performance.  

Does anyone know if it's SAE bolt thread for a 3/4" shaft?  I guessed that on my bid request sheet.  They came back with a 14X9R.   Yanmar 1GM10 and 2.56:1 transmission.  If anyone has info/data to confirm or contradict this, I'd appreciate it.

My Martec can cruise at 6.2 knots at 3000 rpms and I think it should be better than that.  

[John’s Contraptions]

I did mine about 10 years ago and I did not pay anywhere near $1400.

My Flexofold prop is two blade 14X9P - the big story is reverse as it now has one compared to the Martec.  In fact I have a bit of prop walk to port in reverse, something I never had with the Martec.  It's been a while but I think full throttle RPM is just under 3500 RPM and about 6.5 kts.  I would have to check it to be certain

Hull speed = 1.34 X sq root LWL or 1.34 X sq root 26.7 or 6.92 kts so 6.2 at 3k is not bad.

I think the Martec was 13D X 11P

My gear ratio is 2.62:1

I have a old shaft and the thread on the end measured 1/2 - 13 UNC

John

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[Mark Camilleri]

With a Flexfold prop, and a very clean hull, I cruise at 7kts

Regards 

Mark Camilleri

99404089

On 12 Jun 2023, at 18:21, dnewl...@msn.com <dnewl...@msn.com> wrote:

I just got a bid on a Flexofold 2 blade for $1400.  Wow.  But it does seem to get high marks for performance.  

To view this discussion on the web visit https://groups.google.com/d/msgid/j92owners/7d7b9b44-750f-42ab-bb4e-ce2411d3e9c4n%40googlegroups.com.

[dnewl...@msn.com]

Thanks, Mark.  I think the 1GM10 is rated for continuos use at 3400, but I run lower than that.  

Long delivery, what RPM do you/others like?

[Mark Camilleri]

I do t have a Rev meter. Adds weight 😅

Regards 

Mark Camilleri

99404089

On 13 Jun 2023, at 17:50, dnewl...@msn.com <dnewl...@msn.com> wrote:

Thanks, Mark.  I think the 1GM10 is rated for continuos use at 3400, but I run lower than that.  

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[dest...@gmail.com]

Hi All,

I am now looking for a the original Martec folding prop (part # 19220 13x11 prop).   It seems that mine is probably on the harbor floor. (mud really).  When my strut was fixed and the yard put the prop back last year, I bet they didn't install the cotter pins that hold the inside nut... sigh...

Thanks,

Dan Stone

Triple Play #9

[John Madey]

I still have my old Martec (somewhere). I’ll look today to confirm. No reasonable offer refused. Shipping from Chicago USA

John

On Jun 5, 2024, at 11:06 AM, dest...@gmail.com <dest...@gmail.com> wrote:

Hi All,

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[Dan Stone]

Thanks John.  The one I had was 12x12x3/4 so if it is either one of those that will be fine.  Much appreciated.

Dan Stone

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[Dan Stone]

Hi All,

Gori propeller has asked me this, 

"It might be good to know if it is either 3,22:1 (recommendation: 2 Blade 15x10 RH) or 2,62:1 (recommendation: 2 blade 13x9 RH) as we have two options for propellers in those cases."

Anybody know what the Yanmar 1GM10 has?  I would guess the 2,62:1 because the blade size is close to the Martec but I don't know ANYTHING about how this works.

Thanks,

Dan Stone

Triple Play

[, robertpogue]

Hey Dan. I think they're asking about the reduction ratio of the gearbox. I don't recall what mine is, but it's stamped on the ID plate here:

Robert

J/92 #14 Never Settle

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[Dan Stone]

Cool, thanks.

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[Todd Aven]

Here's the "What size prop?" thread:
    https://groups.google.com/g/j92owners/c/uqBPSMzObgc/m/ebvCF6wsEAAJ

Robert is correct, the gear reduction ratio is a key factor in the prop selection. Hull #14 has a RH13DX11P.

On 6/7/2024 8:59 AM, , robertpogue wrote:

Hey Dan. I think they're asking about the reduction ratio of the gearbox. I don't recall what mine is, but it's stamped on the ID plate here:

To view this discussion on the web visit https://groups.google.com/d/msgid/j92owners/CAJhGjYzb%2BJUY8-ZyCEBHPqODv65L4nP0ctaEOgxpwHvFe7Cv%2Bw%40mail.gmail.com.

[Dan Stone]

Thanks Todd!

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[David Newland]

I spent quite a bit of time with prop research and went with a Flex O Fold 13x9r.  1GM10, 2.62 trans ratio and 3/4” shaft with 1 year old rebuilt motor.  Verified tach accuracy.  Cruise at 3000 to 3200 and can make max RPM 3600.  FlexOFold prop calculator recommended a 13x11 but that lugged the motor too much.  They did a free return for the 13x9 blade set.  I spent some bucks but the prop is fantastic and excellent customer service. 

Whatever you buy, ask about return policy.  

Get Outlook for iOS

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From: j92o...@googlegroups.com <j92o...@googlegroups.com> on behalf of Dan Stone <dest...@gmail.com>
Sent: Friday, June 7, 2024 6:43:35 AM
To: j92o...@googlegroups.com <j92o...@googlegroups.com>
Subject: Re: [j92owners] Propeller blues, need suggestions

 

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