Half cutlass (bind) modification

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boathead
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Posts: 33
Joined: Mon May 25, 2020 8:53 am
Location: Chesapeake Bay Mathews va

Half cutlass (bind) modification

Post by boathead »

Just completed this conversion on our boat. Thought a few details of what I did might be helpful to others. From the info from this site the plan was always to epoxy the bearing in place and further secure with set screws .

When you get up close and personal with this project you will discover that the bind fits on the shaft as you would expect but when placed in the tube there is a good amount of place between the bind and the tube. Obviously you need to center the bind in the tube. What I did was to wrap the outer edge of the bind with 1/4 "masking tape until it was a snug fit. This gave me center and a guide to how much thickened epoxy to apply to the bind. Before I started I cleaned the inside of the tube with lacquer thinners , scoured the inside to give the epoxy something to bite on to. Make sure you prime the inside of the tube with un thickened epoxy before the thickened. After the epoxy set up then dig out the masking tape with a pick and use more thickened epoxy in a syringe to fill the gap.
I then used a 5/16 tap and used 3 set screws. Space is tight , the use of a stubby drill bit right angle drill attachments are needed.
Not saying this is the right or best way ,It's just what I did.

Cheers Carl
2003 Hull 28 75 hp Belmar (soon to be renamed KARMA)
home port Queens Creek Mathews Va.(Chesapeake Bay)
MikeH
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Joined: Thu Jan 07, 2021 2:42 pm

Re: Half cutlass (bind) modification

Post by MikeH »

Update from Hull #29 -

Both mid-bearings had detached from the epoxy. The starboard bearing was still intact for the most part. The port bearing disintegrated, and parts and pieces were all the way back in the aft of the stern tube.

I bought Easy Riders without any maintenance history or maintenance logs, so I don't have the details on the original installation.

The original mid-bearing had some type of fiber exterior casing.
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Mike Hendry
M/V Easy Riders, Gulfport FL
2003 PDQ MV 34
The Legendary Hull #29
75 HP, 3 Blade
esheufelt
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Joined: Thu Dec 23, 2021 10:47 am
Location: Oregon

Re: Half cutlass (bind) modification

Post by esheufelt »

I really like this modification because it eliminates the alignment challenge of centering the shaft in the log when you only have the single aft bearing.

As an ex-mechanical design engineer I have a concern that the system is over constrained. Three points don't make a line so now engine alignment is significantly more critical to avoid transmission bearing loading.

It's a good mod but means extra attention.

Proves an old engineering theory called conservation of problems. You don't eliminate problems in systems you just move them around.
MikeH
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Posts: 138
Joined: Thu Jan 07, 2021 2:42 pm

Re: Half cutlass (bind) modification

Post by MikeH »

Amen to that ! ... after much debate on if the mid bearings were really needed at all - since the tubes were already drilled for set screws, we went back in with half BITE's. Filed down the set screws to get below flush. Ran a small bead of 5200 around the middle of the bearing before sliding it in.
Attachments
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20220128_111619.jpg
Mike Hendry
M/V Easy Riders, Gulfport FL
2003 PDQ MV 34
The Legendary Hull #29
75 HP, 3 Blade
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