Wednesday, December 11, 2019

Investigating the rudder shoe

When I started the bottom job project, I had a chance to check the rudder fittings. I noticed a crack in the fiberglass over where the rudder shoe was located at the aft-end of the keel. I was concerned that the crack may be a sign of corrosion in the bronze rudder shoe itself.  Bronze doesn't rust but it does suffer from electrolytic corrosion. The boat rudder rests and rotates on top of this shoe, which is bolted onto the keel. If the rudder shoe fails, the rudder may fall down to Davey Jones' locker.  That would be bad. 

A crack in the fiberglass over the rudder shoe.

Sanding away at the fiberglass layer over the rudder shoe, I discovered that the rudder shoe is fine, with no external signs of corrosion. (Can't find the photo! But trust me.) Because the rudder shoe is made of bronze (note the green oxidation stains) which suffers far less from crevice or pit corrosion in oxygen-deprived environments, there's no need to remove it entirely to additionally check the inside of the shoe for corrosion (unlike chainplates made of stainless steel which do suffer from crevice/pit corrosion and so should be removed entirely when checked.)  The crack was just a thin layer of fiberglass matting that had delaminated off of the bronze rudder shoe. Bronze is far superior to stainless steel for underwater use but like any metal it is subject to electrolytic corrosion aka stray current corrosion. Also, fiberglass-to-metal bonds never last, and inevitably will delaminate. Potentially this exposes the bronze underwater fitting to stray current corrosion once the bronze touches seawater. But this was not a big problem to fix since there was no corrosion. All I had to do was scuff up the shoe surface so it had some "tooth"and then encapsulate the bronze shoe under new layer of fiberglass to isolate it from the external sea water & so avoid electrolytic corrosion. 

The rudder post seemed fine but
we'll see more once I drop the rudder entirely

Investigating further, the rudder post seemed fine, the rudder itself seems fine and is made of solid fiberglass (as with the centerboard) with no signs of water intrusion or delamination. I had repacked the rudder stuffing box but since I've decided to drop the rudder entirely, I will be loosening that up again too.

Here's the funny thing. While stripping the bottom plain off of the rudder, it became apparent that someone had put epoxy barrier coat (gray) over the bottom paint (red). Bottom paint which is not meant to be permanent, is hardly a good base for epoxy barrier coat paint, which is meant to be permanent. I'm guessing someone was doing a rush job, ad instead of sanding off the red bottom paint, decided they could hide it all under a layer of gray barrier paint anyway, so who would know? Not the owner.  Luckily the epoxy barrier coat did stick, mostly.  I'll have to it all off of course, but this, to me, is yet more proof that in the marine services industry, you really have to do it yourself and can't rely on yard workers to care as much about your boat as you.  

Stripping Bottom Paint

One of the benefits of the new yard location for Whimsy is that we're allowed to do our own bottom-jobs. (Due to environmental concerns, most yard won't allow this.) Needless to say the red anti-fouling bottom paint on my boat had long expired and needed to come off. I also wanted to check everything under the waterline, to make sure there were no hidden surprises under the anti-fouling, and to take care of a couple of projects including checking the rudder shoe.

Options for removing old antifouling bottom paint layers are: sanding, stripping with chemical stripper, or blasting (usually with something relatively soft like walnut shells, to avoid damaging the fiberglass gelcoat beneath the antifouling). Since blasting was not allowed in the yard and I wasn't a sucker for punishment of sanding, I decided to try the paint stripper option. Let me emphasis just how horrible sanding a boat bottom is: the paint is a biocide so you have to wear protective clothing and masks, in 90+ hot muggy weather, as you exhaust yourself  waving a heavy grinder upside-down, pressing it up against the bottom of the boat, as sweat mixed toxic dust rolls down into your eyes and you can't breathe easily through the mask. This is one of the worst boat-repair chores there is.

I bought pail of Peel Away paint stripper from the local hardware store (about $50/pail), and tried a test patch on my hull. This material is basically drain opener chemicals but in cream form, which you smooth over the hull with a 1'4" notch trowel. Cover it with the paper/plastic sheets provided, tape the sides of the paper down to make sure the stuff stays moist for as long as possible, and wait overnight.

 The chemical stripper worked amazingly well when washed-off with a power washer.  It came off easily, leaving only small stubborn spots of red bottom paint that sanded-off easily.   

The area around my boat was an environmental atrocity, flooded with several inches of orange-colored slurry. (The main ingredient of bottom paint is copper, which is a biocide.) And once it all dried, the antifouling turned into dust and settled on everything including my car and my coffee cup. Yet this is normal in the yard, and worse has been happening here for several decades since the Navy owned the place. I suspect this is where I will catch cancer!

WARNING: Peel Away is highly corrosive so I suggest taking all the necessary precautions (especially eye protection and gloves.) A little bit of it was accidentally smeared on the inside of my wrist, under the glove, and now have a scab there. I'd hate to think what could happen if even the dust from the dried-up material got into anyone's eyes - so I suggest not only eye protection but also keeping a water hose nearby and handy as an emergency eyewash station.

The stuff I used was the regular hardware store version of Peel Away that comes with a plastic spreader, some pH testing strips, and the plastic/paper sheets used to cover the area being treated, and a packet of neutralizing powder (which I suspect is a mild citric acid. Vinegar also works.) Peel Away makes a "safe" version for use on boats that won't damage underlying gelcoat, which I also tried. (Since my boat had an epoxy barrier coat under the antifouling, I wasn't worried about gelcoat damage using the regular stuff.)  The "safe" marine version is slightly runnier, so you need a better trowling technique especially on the upside-down surfaces of the keel, to avoid plopping the stuff all on the ground. They were both equally effective.

I had to buy 6 pails of Peel Away to complete the project but in the end I got a nice clean hull with no sanding. Of course, then I had to sand it all with 80 grit in preparation for the new coat of barrier paint. While sanding, I occasionally accidentally went through the old barrier coat and got to see the gelcoat underneath, which while crazed was still in decent condition. There's no sign of pox or blisters; boats as old as Whimsy generally didn't have problems with blisters. I figure, if there was going to be osmotic blistering, she would have shown it by now. However a couple of extra coats of epoxy barrier coating won't hurt either

Also, while the antifouling is gone, I want to check out the rudder shoe and investigate a worrying crack in the fiberglass around there.

Moving to new boatyard

The boatyard where I started working on Whimsy has decided to gentrify, cater to big fancy catamarans and open a seafood restaurant. Needless to say DIY-type liveaboard types were no longer welcome and we were given a deadline of Nov 30 to leave the yard. Which is too bad because it was a great location, very centrally-located to all the stores I regularly visited plus relatively close to my storage lockers where I keep my tools and supplies.

St John's River

Unfortunately the new yard is not nearly so well-situated, though only 30 minutes West of my previous location. The nearest store is a 20 minute drive; the nearest hardware store is an ACE branch that is not really adequately stocked compared to the large Lowes and Home Depot I used to visit, and getting to my storage unit is a pretty long drive. Not to mention the new yard is almost twice as expensive and the boats are jammed together quite tighly (that may resolve as more of the snow-bird Canadians splash their boats soon.)

On the more positive side, the new boatyard is obviously more oriented towards the DIY crowd. There are grizzled old snaggle-toothed guys here who look like they've been working on boats their entire lives. Actually some of the boats here look like they're pretty permanently on-the-hard too. Yet there are plently of cruisers -- lots of Canadians -- who are working diligently on their boats from early in the AM when the rooster crows (yes, there are chickens and ducks running around too) 'til dusk and sometimes into the night, sanding and polishing and painting things. It reminds me of the mothership scene in Water World, the post-apolocalyptic movie with Kevin Costner. 

But I see all this as just further encouragement to get going and finish up my project.

More importantly, this yard allows people to do their own bottom-jobs (though no blasting) so that allows me to save a lot of money rather than having a yard do it. The estimates I was hearing were well over $2500. The cost of the move to the new yard was $1400 but apparently most of that is in the loading/unloading of the boat, the mileage itself is quite reasonable. That means that I could have kept going south to a boatyard that was a in a warmer clime  - and I may still do so, since I can't paint the boat with the average temps around here for Jan and Feb. On the other hand, there are enough other  projects to keep me busy until the weather warms up.