Ericson/Olson 34 shaft strut; No joy!


Member III
I thought I'd share this weeks maintenance on Loki.

I contracted a local mobile marine mechanical group (very reputable) to replace the shaft seal on Loki. The seal replacement uncovered issues with the shaft coupling keyway, which lead to pulling the shaft, which uncovered wobble in the bedding of the strut. I had injected the area with epoxy about 5 years ago, but the wobble had reappeared. I decided to move on with a permanent fix.

The mech ground out the glass that covered the strut bolting on the inside of the hull to expose the true issue with the wobble.
Strut Inside2.jpg When the strut was originally installed, three bolts were inserted through holes in the strut to hold it in place, then totally glassed in on the inside of the hull. The bolts are not attached to the strut at all, simple slid through the holes.

Looking up from the outside of the hull:
Strut Outside1.jpg You can see through the gap, the bolting run through the strut on the inside of the hull. I assume this was done by the stoners in Santa Cruz in 1990 when the hull was outfitted.

The strut has been removed. I'll have a bronze plate welded to the end, and bed the strut properly while aligning the shaft.

And so goes this years boat maintenance budget.



Olson 34 Strut Woes

Sorry to see your '18 maintenance budget go "poof!", but if it's any consolation, it appears you've taken a course of action to fix a problem endemic to these Olsons and stabilize the strut forever (or until the end of your stewardship).

Roughly 5 years ago I had a similar experience, but not to the 'see through' end of the spectrum you have. The strut wobbled, with a side-to-side throw of @ 3/8"+. The PO chose to goop epoxy, badly, along the strut/hull interface. Of course it didn't hold and over time chunks of epoxy dislodged. Not pretty, as evidenced in the 'OMG! I guess I need to fix that!' picture.

I could swear I previously submitted my fix procedure to the site after it was completed, perhaps there is something to this early onset diagnosis (sick joke, just kidding).

The images are out of sequence, the bottom left image shows how the strut looked once exposed by prone-on-stomach Dremel® work. The top left image shows the fully ground out (more Dremel® work = ugh!) to provide a cavity for the thickened epoxy, which became a shmooshed flat surface for the T-plate to eventually mount to. The top of the strut shows the 2 holes drilled and tapped to completion...and the 3rd hole that was a bugger to drill and eventually abandoned, accompanied by a string of explicatives heard only by my ringing ears.

The top right image, with the plate installed to the strut, shows the 3 screws on each side not yet installed. Those 6 screws, penetrating @ 3/4" into the thickened mound of OEM glass, pick up the lateral loads, similar to what your welded plate will do.

These pics personify 'hill billy engineering', with the strut stabilized throughout the process on the outside by a furring strip concoction screwed to the concrete floor, so as not to alter the prop shaft orientation. There was a fair amount of 'skull time' ciphering spent on how to go about a fix I could enact.

The strut has been rock-solid since. I believe yours will be too. I won't wish you luck, 'cuz it appears you won't need it. Enjoy the process, please send pics of the strut before you install it, as I'm sure those that follow will take full advantage of your effort.


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Struttin' Stuff (continued...)

Thanks Andy, for resurrecting the 'What's under the bump?' Thread. I guess it's appropriate to write "I see, said the blind man, as he picked up his hammer and saw..."

We now return to our regularly scheduled programming.

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
And here we all are in 2021, emerging from the worst (hopefully) of a once-a-century pandemic, and this subject comes again for another owner. Lucky me, our strut is solid. The future, as they say, is "out there".
Hope that someone benefits from more info about a good repair procedure.