Strut Leak

[Tony]

Hey all,
We splashed our Hardstad 31 yesterday and abruptly put it back on the trailer when water started welling up from an unknown leak from the prop shaft strut area. It's connected to the boat with sealant and 6 bronze bolts. I spent the morning grinding away a lot of poorly applied glass and resin that was covering the strut bolts and am now down to the wood backing board. I can't find any structural problem, so my running hypothesis is a PO found a leak and instead of fixing it, just slapped on some glass (1-2 layers of glass cloth, poorly saturated with voids and air pockets, and pockets around each bolt head) for a temporary fix. I must have stepped on one of the "bubbles" and popped it. My next guess is the leak is coming through one or more bolt holes. The bolts are heavy bronze ones, about 3/8" (The nut is a 9/16 socket). The bolt heads are rounded (I'm not sure if they originally were, I may have rounded them off when grinding away glass), with a slot across the top. I unscrewed the nuts, which were pretty loose, and am now trying to figure out how to get the strut off to rebed it. All this for a couple questions:
1) How do get the prop off the shaft? The prop nuts came right off, shockingly, but I don't know anything about props. Do they just screw on the shaft, are they held in with a key, or what? Note that there is no engine connected to the other side, I pulled it out of the engine bay last week.
2) How do I free the strut from the hull? The boat is a '77, so I doubt its on with 5200. The hull is a pretty thin layup, according to the designer is something like cloth, 1/4" ply, cloth, mat, mat, cloth for a total af about 1/2-5/8" thickness. I am thinking of trying to work it loose with a small wrecking bar, but am concerned about damaging the hull any more than it already is....any suggestions?

Also, I'm having trouble finding a local source for replacement bronze bolts and nuts, so do any of you know where I might order them online?

Thanks a bunch,

[Tim]

Tony,

You need a prop puller to remove the prop. You might be able to borrow one from a yard, or helpful neighbor. The prop fits over a tapered shaft, so as it's installed, the fit gets tighter. This means that getting them off is difficult. Don't bang on it--find a puller. And watch for the key when you get the prop off--try not to lose it. You might also be able to buy a puller locally. I keep one on board--there are few more helpless feelings than needing to remove your prop, but being at the mercy of someone else providing the puller.

Do you need to pull the prop in order to rebed the strut? Or can you just unbolt the strut and rotate it out of the way for whatever surface prep you need to do? To break the strut free, once it's unbolted (and the bolts removed), use a thin (but strong) putty knife to score and then break the seal between strut and hull. If it's leaking, it's not going to be that tough to remove, probably. Once you get loosening the seal started, the rest should be easy. Those "5 in 1" tools you can find at the hardware store are often good for this--you know, the putty knives with the scalloped edge and wide blade tip? Start with small tools and work up to stuff like wrecking bars only if absolutely necessary. (It shouldn't be.)

When you rebed, use a tube of polysulfide. Use tons--you don't want another leak. Since the strut is something you might want/need to remove again at some future date, don't use 5200 (though you could, if you wanted--just makes removal more difficult)

Order bronze nuts and bolts from Jamestown Distributors. www.jamestowndistributors.com. They have silicon bronze on all shapes and sizes.

[Figment]

And since you have the engine out of the way, you might be able to bring the shaft out the back way.... remove the engine coupling with a common wheel-puller. That's IF you can get the shaft past the rudder with the propellor still on. I'm not familiar with the Hardstad.... just throwing "if"s into the mix.

So your hull is 'glassed plywood. And you've got a leak at a bolt hole. It seems likely that you'll have some saturated plywood in that reigon. I think the fact that the nuts were loose suggests some compression of the composite as well. Have you investigated this?

Whadda you think, Tim? Might there be more to this than simply rebedding the strut?

[Tony]

Good point, I was already planning on re-building that section of the hull. I don't know for sure if there's plywood core there or not. I found plywood when I put in the new seawater intake, which is about 6-7 feet away. In the strut's case, there is a seperate, additional plywood backer plate besides the hull layup. I was planning on grinding out the rest of it and building up a glass plate there. Oddly enough, the plywood backer does appear to be pretty solid, with no obvious rot or saturation, however. As for the Hardstad, there were only about a dozen made. It's a Bill Crealock design, and is really just a Clipper 32 with a "pilot house." It's nowhere near as pretty as your boats, but when we were looking at boats, had not really discussed living aboard a whole lot, and I heard my wife say to herself.."Hey, I could live here..." Who was I to argue? :-)

I'm going to try to get the old bronze bolts out tonight...I'm not really expecting them to just spin right out, but a guy can always hope.

Fair Winds,

[Guest]

I'm going to try to get the old bronze bolts out tonight...I'm not really expecting them to just spin right out, but a guy can always hope.

One reason I'm so fond of bronze: The high copper content gives it great (heat) conductive properties, and a relatively high coefficient of thermal expansion. A little heat goes a long way when some "persuasion" is needed.

[Tony]

OK, going back to my physics classes in college...the bolt is in fiberglass, heat causes molecules to be excited, and expand, so if I'm causing the bronze bolt to expand, how does the tighter fit make it easier for me to get it out?

Tony

[Tim]

So your hull is 'glassed plywood. And you've got a leak at a bolt hole. It seems likely that you'll have some saturated plywood in that reigon. I think the fact that the nuts were loose suggests some compression of the composite as well. Have you investigated this?

Whadda you think, Tim? Might there be more to this than simply rebedding the strut?

Good point. I didn't really focus in on the potential core thing (it was early in the morning and I was rushed when I replied), but NOW is definitely the time to determine if there's any water infiltration there. If so, it requires repair at this juncture.

If the area is indeed cored, and it manages to be dry despite the seeming leakage, then take this opportunity to remove the core in way of the bolt holes, so that even if future leakage occurs you won't risk contaminating the core. Plywood gets wet very easily, and can delaminate into nothingness very quickly depending on its quality to begin with. High quality plywood may get wet, but will retain its structural integrity for a long time even if saturated.

Good luck, Tony. This particular project is living proof of the general rule for boat repairs: one thing always leads to another, whether you want it to or not!

[Figment]

The heat thing....

I agree, it's counterintuitive. But it works. The tricky part is knowing when to STOP.

As far as a bolt stuck in fiberglass/epoxy/FRP goes, it's simple: heating the bolt melts a thin layer of the resin, releasing the bolt. Let's say you've forgotten to wax a screw before driving into green epoxy.... hold a super-hot soldering gun to the screw head for ten seconds or so, and she comes out like butter.

For metal-to-metal struggles, I seem to recall a long-ago explanation to the effect that briefly and intensely heating a bolt or nut is enough to cause it to expand faster than its counterpart, which can help to break stubborn corrosive bonds.

[Tony]

OK,
The good news is the hull isn't cored with plywood in that particular area...happy day :-) I chisel'd out the teak (ouch) plywood backing plate and then used vice grips to turn out the old bolts. 5 of 6 came out real easy, actually. The last one broke, unfortunately, and so far I've been unable to extract it, since the bronze is so soft the extractor just strips out the hole. I layed (laid ?) down 6-7 layers of glass and mat last night before I ran out of resin (darn it!) and discovered why the strut was leaking. 1)The strut is off center. Some helpful individual put a steel "spacer" (an short piece of steel with holes in each end, like a 1.5 inch chainplate) between the center starboard bolt to make the strut hang evenly, which left space between the strut and hull. 2) Probably the same individual had to bore out the bolt holes on the starboard side due to the previous modification, which means you've got a 3/8" bolt in a 3/4" hole. 3) Perhaps the builders, or the same individual, used 2" steel washers under the bronze bolts, which corroded, allowing water that made it past the defective seal, up the bolt holes and past the bolt heads to collect there. When the thin glass was broken there atop the bolt heads, voila! Instant boat leak you wouldn't know was there. I filled in the bolt holes with thicken'd epoxy and am now deciding how to approach redrilling and reinstalling the strut. Of course, I still have to get the other bolt out of the strut still.

An interesting piece of trivia, I found out yesterday we have hull #1.

Fair Winds,

[Tony]

Another Question:

How do you remove the coupler from the prop shaft? I've found two holes, opposite each-other. Is there something I need to drive out of the hole, or is it connected some other way? The shaft is gouged in a couple places and I have to do some machining on the strut, so I've decided just to remove the whole thing and plug the holes until we get another diesel.

Thanks,
Tony

[Tim]

The two holes are probably where setscrews are supposed to go--these are designed to project slightly into dimples in the shaft and help hold the coupling in the proper location. If the setscrews were there, you'd know it--they typically extend out of the hole by an inch or so. Check inside the hole and see if there's anything there. But it sounds like there isn't.


If the shaft is gouged in a couple places, and you're replacing the diesel, then don't even bother removing the coupling. Your new diesel will come with an appropriate coupling, and it sounds like you need a new shaft anyway.

Of course, this assumes that you managed to get the prop off, and can therefore pull the shaft out from inside the boat. Do you have clearance for that? If the old engine is in the way, remove it now, since it sounds like you're planning on that anyway.

If you can't do any of this, or need to/want to save the old shaft and/or coupling for whatever reason, then soak the coupler in PB Blaster for a couple days, and then use the oft-documented method of coupling removal that involves replacing the bolts that secure the coupling to the transmission flange with longer ones, or threaded rods, and using a socket or dowel no larger than the shaft diameter as a spacer between the two halves of the coupling. Then, by tightening the bolts (or threaded rods), you can slowly press the coupling off the shaft.

[Tony]

Ah ha,
well, had I known this before I pulled the engine out of the engine bay and onto the saloon floor (with a come-along, 20 feet of chain, my anchor line, much grunting and cabinetry destruction), I indeed would have pursued this direction. Unfortunately, the transmission flange is about 6 feet from the coupling on the prop shaft. So, is my only option cutting it off? I have not removed the prop, I was thinking I'd unship the rudder (It's transom mounted) and pull it out that way.

[Tony]

And no, I've not got the prop off yet. I haven't found a prop puller (working 12 hour days means when I get off, everything's closed)

[Tim]

Tony,

To remove either the coupling or the propeller from the shaft, you need something against which to pull, at whichever end is opposite the end you're working on. Therefore, pulling the prop with the coupling removed or detached from the engine will be difficult or impossible--the prop puller exerts a lot of force on the propeller hub from the leading edge, and without the shaft bolted to the engine the puller will simply try to pull the whole shaft out.

Likewise, removing the coupling without the engine transmission flange to pull against will be difficult, at least. If you have access, you can sometimes have success (after thorough PB Blasting) banging the coupling off the end. But this tends to be an exercise in frustration and raised blood pressure, usually culminating in aborting the attempt. If the shaft was out, on a bench somewhere, you might be able to get the coupling off this way. In the confines of the boat, it'll be tough. On the other hand, you could get lucky, too!

You said the shaft was scored. Where is it scored, and how badly? Do you honestly think it is something you will end up reusing, or do you forsee the possibility that you'll require a replacement? What size is the current shaft? If it's smaller than 7/8", you'll probably need (or at least ideally have) a new one for your new diesel.

Balance your own time, potential frustration level, and difficulty of the task ahead against the liklihood and relatively minimal cost of a new shaft, and then proceed accordingly. Pulling apart shaft components that have been in place for many years is definitely one of the more difficult tasks you may face. Good luck.

[David]

Tim,

Doesn't the prop puller work by pulling the leading edge of the prop hub against the rear center of the prop shaft, thus breaking it loose from the tapered shaft and key, like a gear puller works? Whether the shaft is connected to anything at the other end wouldn't hamper pulling the prop...at least the ones I have used work this way...Maybe I am not following your explanation.

David

[Figment]

Tony,

To remove either the coupling or the propeller from the shaft, you need something against which to pull, at whichever end is opposite the end you're working on. Therefore, pulling the prop with the coupling removed or detached from the engine will be difficult or impossible--the prop puller exerts a lot of force on the propeller hub from the leading edge, and without the shaft bolted to the engine the puller will simply try to pull the whole shaft out.

Likewise, removing the coupling without the engine transmission flange to pull against will be difficult, at least.

Huh?

I must be missing something here. To my mind, having the engine out makes this EASY, not hard.

With the engine out of the way, separating shaft from coupling is a job for an everyday $8 wheel puller (aka "gear puller") available at any wal-mart or auto parts store. twist twist, tap tap, twist twist, tap tap and off she comes. ten minutes, maximum. The biggest challenge might be finding a way to jam a pair of vice-grips against something to counter the rotation of the puller's screw.

As for pulling the prop without the engine attached.... The only prop pullers I've ever used operate by pressing the shaft through the hub of the prop (operating on the same principles as the wheel puller). Never any force transferred to the engine.

[Tim]

Must've still been asleep when I wrote that this morning. You're right on all counts, of course.

[Figment]

heh heh. Gotta start checking the board AFTER the morning coffee!

You KNOW we can't resist jumping on things like that, host or no!

:)

[Tim]

You KNOW we can't resist jumping on things like that, host or no!

As well you should! You guys keep me on my toes, for sure! ;<)

[Tony]

Remember that older post, sometimes it's just so easy?

I was ready to cut the coupler off, but I figured I'd make a few half hearted bangs on the coupler before breaking out the sawzall, then I heard a muted bang outside...the prop literally fell off of the shaft, followed by the strut. Go figure. Anyway, the holes are glassed over and we're in the water. (I"ve got to rebuild the shaft tube anyway, as I discovered it was cracked, so I figured I'd deal with it when I put the new engine in.)