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Sat, May 28 2022, 12:07Login ] [ Contact Forum Admin ] [ Main index ] [ Post a new message ] [ Search | Check update time | Archives: 123456[7]8910 ]

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Date Posted: - Friday - 09/15/06 - 5:20pm
Author: marcus
Subject: prop size m31 w/ perkins 4-107

Hello: I have what seems like a relativly small 2 blade prop on my boat. has anyone used a 3 blade prop? My baot seems a bit underpowered, or it could be just the rasta dreadlocks I havn't really scrubbed off on the Bottom. Pleade report on you prefered prop sizes for the perkins 4-1-7.

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[> Transmission Ratio -- Capt'n Mike - Gypsy Mariner TM36K, - Friday - 09/15/06 - 6:49pm

You can run either a 2 or 3 blade prop, but I'd need to know what your transmission reduction ratio is to run a calculation. For instance, if you are running a 1:1 transmission AND given the M31's displacement (11,500 lbs) and LWL (25'8") and the SHP for the 4-107 (figure 40), you should be able to run a 2 blade 11 or 12 inch prop with a pitch of 5 or so. The 4-107 is more than enough power for the displacement of the M31. You need to check the pitch of your prop AND make sure it is not covered with marine growth. A few barnicles on the prop will have a noticeable effect on power output. However, if you are running a reduction ration of 2:1 then you could swing as much as a 17x10 2 blade, if you have the clearance for it.

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[> [> $-107 prop size -- Doug Wilson ,Cactus Tree, - Friday - 09/15/06 - 11:22pm

Cactus Tree has a two blade sailor 12". It must be the original, had Japanese charactures on it and metric numbers.I believe I have a Borg Warner gear, 1 to 1 reduction. I get 5 KNTS at 1300.
Wilmington prop tuned it up and it was in great condition.

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[> [> prop -- Randall, Murre, M31, - Monday - 09/18/06 - 12:39pm

Murre runs a three blade 12 inch, 6 pitch prop. Capn Mike's reference to transmission ratio is crucial to your decision. I put a three blade 13 x 8 prop on Murre for a while (seems to be common among other M31s), but couldn't get appropriate RPMs.

Figured out later that the prop was too big for my 1:1 tranny, and a 12 x 6 is a perfect fit (i.e. plenty of reserve power).

I've stuck w/the three blade (the boat came w/a two blade stuck away in a locker) because we do plenty of headwind motoring and plenty of high wind sailing, so the extra drag, for us, is worth the trouble.


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[> transmitions bearing for M31 -- Ardian, - Tuesday - 12/19/06 - 5:07pm

Hi ! I need to know what's the size of the bearing at the shaft because i need to replace it due to leaking. this is for M31 1970

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[> [> Cutlass Bearing? -- Capt'n Mike - Gypsy Mariner, - Friday - 01/ 5/07 - 9:35am

Do you mean the cutlass bearing? If so, the size of the shaft on my Tayana Mariner 36 is 1.25 inches, but the 31's may have a smaller shaft diameter. You may be able to get a caliper around the shaft from inside the boat and measure it.

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[> [> [> What Size is Your Packing? -- Terry "Matang", - Tuesday - 01/ 9/07 - 12:25am

Hi Captain Mike
Since I have a 36 also and have never change the packing glade I am wondering what size packing I need. I also have 1.25" shaft.

Also, I am wanting to know what size standing rigging you have on the main and mizzen. I think mine is oversized.


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[> [> [> [> Shaft Seal and Rigging Size - TM 36 Ketch -- Capt'n Mike, - Tuesday - 01/ 9/07 - 9:31am

Hi Terry,

Gypsy Mariner has a Lasdrop dripless mechanical shaft-seal.

As for the rigging size: the main dual backstays and lowers are 1/4". The main forestay and uppers are 9/32". The triatic stay is 3/16". All of the mizzen rigging is 3/16". The bobstay is 3/8".

If I oversized anything, it would be the mizzen rigging wire from 3/16" to 1/4" - not really because it needs it, but to keep most of the standing rigging size uniform for repair purposes. I use Sta-Lok fittings.

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