Help With New Strut Installation

Ex Hobie Sailor · **Posted:** 07 Nov 2017 09:27

Hi Everyone,
Any tips on installing new strut on Tartan 37. Having one made now, mine is not terrible, but in questionable condition. I will not remove old until have new in my hands. Chicken I guess. Does strut have to be shimmed against hull or does it just bolt up, and adjust alignment with motor mounts. I have read a thread on sailnet about using Dyna Glass compound to shim strut to align with shaft. They used packing tape as a release agent on strut mount to be able to remove. My new strut should come with all holes pre-drilled. On sailnet thread, after shim was farbicated owner drilled down through strut mounting holes in hull and just into strut, removed strut and drilled mounting flange and reinstalled. The problem I was anticipating was If my strut [img]comes pre drilled, how do I line up mounting bolts and shim with Dyna Glass if necessary, and remove bolts and rebed and reinstall. I was thinking wrap packing tape around bolts so they will release from Dyna Glass. Not sure If I am overthinking the job, this is my first strut replacement.
Pictures of my strut at preset, seems to have gotten worst since last year. I installed (1) Shaft Zinc in 2016 season and was very eroded at haulout in the fall (Home port Long Island, NY), so I Installed Galvanic Isolator, (2) HD Camp shaft zinc's this season. Shaft zincs barely eroded, I tested for continuity between shaft and strut, all good. Was also of thinking (1) shaft zinc and (1) on new strut for next season. Anyway, and help or suggestions will be appreciated.
Thanks,
Todd McCarthy
S/V Bleu Moon Hull #439

berwick · **Joined:** 21 Oct 2006 18:12 **Posts:** 327

I had taken my strut off to rebed 5-7 years ago. The spacers that were under the strut were made of some sort of metal but I put them back. A few years ago I was getting a bit of a wobble when you look at the end of the stuffing box, so took everything apart. I could tell the strut was out of alignment because it was almost rubbing on the top and port part of the stern tube when I took off the stuffing box. I took off the strut, checked the shaft, redid cutlass bearing and repacked the stuffing box. The weird thing was my spacers were gone but the strut still seemed tight! Anyways I made a bunch of spacers out of 1/16" G10 fibreglass and lined the strut to the middle of the stern tube - then aligned the engine to this. After I put the stuffing box back on and no movement at all now and less leaking at the box. I had to play with the spacer thing a bit but in the end it worked out and they should not dissolve like the others did,

Richard

Ex Hobie Sailor · **Posted:** 07 Nov 2017 21:22

Thanks Richard,
Wasn't sure what to expect, job was starting to scare me a bit. I have seen worse pictures of struts , but have noticed some erosion and think I'm border line. Anyway, I ordered new strut from Algonac Marine Cast. Good Idea with the G-10 board to shim. I just put new cutlass bearing in and have alignment set up, but looking at strut know the writing is on the wall. I have strut press tool, PO removed strut to install cutlass bearing a few years ago. Hoping they didn't glue it back with 5200. Any opinion how bad the dezincification is on my
strut ? I cleaned it up with an angle grinder and wire wheel. I have had the boat 3 seasons, and plan on keeping her awhile. Have done tons of work on her already.

berwick · **Joined:** 21 Oct 2006 18:12 **Posts:** 327

I think the strut looks fine except for the 4 holes on the side, is that what you are concerned about - I have not seen that before. I have a strut zinc that attaches to the strut that doesn't wear too fast but seems like a good idea to me

Richard

Velera · **Joined:** 29 Dec 2006 09:38 **Posts:** 656

OK. I would say that it is not a bad idea to replace that strut. It is getting a little bit pink. Pink means the alloy is breaking down and getting weaker. Probably not a huge problem, but you are smart to do it. I replaced mine 20 years ago and it still looks fine. They will last a long time if you keep zincs on them. They go fast in hot marinas with lots of stray current and when they are poorly zinced.
I put my new strut on by putting mold release wax all over it and positioning it with the bolts so that it was perfectly aligned with the shaft and a new cutless bearing with the down tube centered and aligned as much as possible with the engine. I had gooed up the area around the base with West System in a peanut butter consistency with hard adhesive filler. Everything was held in place with blocks and clamps until it went off. I had prepared the inside with a couple layers of mat glass so I needed to drill new holes for the bolts (from the outside using the new strut holes as a guide) and I think I had to fabricate a new backing plate for it. The next day I took everything apart to make sure that it did not need shims (sometimes West System shrinks a bit when it dries) but it was OK. I gooed it up with 4200 and put it together. Never had a problem in probably 30K miles and having hit some logs and big line with my prop. You have the opportunity to get it better aligned than when they made the boat this way. The factory had to do all this when things were still moving around in relation to each other.
Use two zincs on the shaft. Another on the propeller if it is a feathering one, and another on the strut (you might have to drill a hole for a disc zinc). You cannot “over zinc” a fiberglass boat (wood boats with copper and other electrolic fasteners are different matter). You want the zincs to show some deterioration over time because they must do that to save your engine and other metal parts from dissolving. If your zincs look good when you take the boat out after a year or so, I would be worried. I have found that the quality of zincs varies by batch- even from the same manufacturer. Remember to hit them with a hammer and tighten the bejesus out of them (do it a couple times over a couple days) because the ones on the shaft can loosen and start an annoying vibration.
Good luck with this. This is one of the few jobs that could be a once in a lifetime event.
Ray Durkee
T37 #373

Ex Hobie Sailor · **Posted:** 08 Nov 2017 22:58

Extra holes on Starboard side of strut were for Spurs, they are now mounted on port side, that is how I bought the boat. The last hole was for a set screw, which is missing. Thanks Ray for the guidance, your help is much appreciated. By fiberglassing the old strut holes in the hull and re drilling them makes sense. The strut will be self aligning this way with the West System peanut butter mix. Started thinking about the shaft also, but it seems pretty good, slight play in new cutlass bearing, but very slight. I was happy to find someone who would make a new strut for a reasonable price, Essex Bronze casting wanted twice for the strut. When Algonac Marine Casting they said they had the plans and mold, I just ordered it. One and done !
Thanks Again,
Todd McCarthy
T37 #439

Ex Hobie Sailor · **Posted:** 08 Nov 2017 23:15

Ray, Just wondering how you clamped the strut ? I saw a picture of someone with an articulating boat stand holding the strut in place while epoxy was curing.
Thanks, Todd

Ex Hobie Sailor · **Posted:** 09 Nov 2017 07:07

Hi Ray,
After 20 years you have an amazing memory, I usually can't remember what I had for dinner !
Todd

Velera · **Joined:** 29 Dec 2006 09:38 **Posts:** 656

As I recall, I just cobbled a 50 gallon barrel under the prop and strut and put some large blocks (the boat yard kind for keel blocking) and then some small scraps to fine tune it. I recall going up and down the ladder a lot to make sure everything was right inside the down tube before I gooped it up in place. The set up was not very attractive, but it worked. Unless your shaft is compromised with some wear, I would be a bit concerned about slop in the cutless bearing at this point. It ought to start out right. Are you sure you have the right sized one? If your shaft is that compromised, this might be the time to do something about it.

Ray Durkee
T37 #373

Ex Hobie Sailor · **Posted:** 10 Nov 2017 09:21

Hi Ray,
You are right, now is the time to do it when strut is off. Is there
Enough play with the strut off to slide out past the skeg ?
Thanks, Todd

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Help With New Strut Installation

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