ALUMINUM HULL ANXIETIES: Return of the Leaky Rudder Skeg and More Bottom Paint Rumpus

Lunacy hauled out

Lunacy got hauled out at Maine Yacht Center soon after we arrived there from Bermuda last week, and yesterday I went up to have a look at her. As you can see in the photo up top, there’s very little bottom paint left on her nether parts. She’s been mostly bald like this for most of the winter. Since taking her down to Puerto Rico last November, it’s been a battle keeping the growth off and she’s had her bottom scrubbed five times–three times by me and twice by divers. Besides being too soft to stay on the boat for a full year, or after a few scrubs, the ablative copper-free Ultima Eco paint I had on didn’t seem to be an effective deterrent to life in tropics.

So I was wrestling with the big question: do I finally abandon my quest for an effective copper-free paint? Is it time to resort to the “nuclear option”??? The MYC service manager Jeff Stack and I discussed what would be involved, i.e., lathering on more barrier coating in hopes of keeping a hard, or semi-hard, copper paint separated from Lunacy‘s vulnerable aluminum self.

Troll the Internet for opinions on this subject and you’ll find a perfect ying-yang of truth and certainty. There are those who are perfectly certain that putting any copper paint on an aluminum boat is suicidal, no matter how much barrier coat you have between paint and hull. And there are those who are certain this is no problem at all, provided the barrier coat is intact. I have in fact never heard of an aluminum hull being eaten by paint–all the horrible corrosion stories you hear are of boats being eaten inside-out, due to junk in their bilges. So the nuclear option, at last, was seeming pretty tempting.

Skeg drain

Paint, however, turned out to be the least of my worries. On pulling the plug at the bottom of Lunacy‘s rudder skeg, I was mortified when I saw water pouring out–about a pint’s worth–which means, most probably, that the weld at the top of the skeg once again has a crack in it somewhere.

Loyal WaveTrain riders will recall we had this same problem four years ago, soon after we suffered through the ordeal of the sponge blast.

So now I’m in denial mode. Fuck the paint. Fuck the skeg. It’s June. We’ll put on some more Ultima Eco, splash the old girl, and keep sailing until fall. Then we’ll confront reality.

Clock and barometer

To assuage my disappointment re the rudder skeg, I treated myself to the fun job of installing the new barometer and clock I bought at the Miami show in February. They look pretty sharp, don’t you think?

I also spent a little time roaming the MYC shed, where I found:

Keel surgery

My buddy Phil Cavanaugh’s boat Alida undergoing extensive keel surgery, this as a result of him parking her on a rock for a few hours last summer.

Akilaria Gen 3 cockpit

Aklilaria Gen 3 bow

Akilaria Gen 3 stern

There are also two new third-generation Akalaria Class 40s in the house getting prepped for their owners. Features include a retractable hard dodger that slides back and forth over the cockpit and a very serious hard chine that runs most of the hull’s length from bow to stern.

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7 Responses
  1. Richard Elder

    Every time I see a skeg like this I have to ask the question, is the rudder supporting the skeg or the skeg supporting the rudder? I did a load cell deflection test on just such a design (in glass) once before deciding to cut the skeg off and build a bulletproof balanced spade rudder to replace it.

  2. Charlie

    @Richard: Yes, exactly. I’m coming to the conclusion that the ultimate solution here is either a) rebuild the skeg so that its structure is carried up into the hull and tied into the frame; or b) 86 the skeg altogether and put in a balanced spade rudder. charlie

  3. Richard Elder

    The great thing about a vertical transom/sugar scoop/external bearing rudder is that it can be made hell for stout and easy to maintain. My idea for the perfect design is to make the rudder a balanced spade with the ability to pivot under extreme duress. Upper bearing mount with a secondary pivot shaft. Lower bearing saddle held to the transom with fuse bolts, and back up bolt attachment points ready to go. V shaped cutout in the sugar scoop. Sealing plate mounted to the top of the rudder, lightly built to self destroy if the rudder ever pivots.

    Look out you whales!

  4. @Richard: Yes, exactly. I’m coming to the conclusion that the ultimate solution here is either a) rebuild the skeg so that its structure is carried up into the hull and tied into the frame; or b) 86 the skeg altogether and put in a balanced spade rudder. charlie

    How is the rudder/skeg load transmitted to the hull now? Is there a substantial structure?

  5. Charlie

    @Don: No structure at all. The skeg, as far as I know, is simply welded to the bottom of the hull. It is also partly supported by the rudder itself (as Richard has remarked), which in turn is supported by two external bearings on the transom. I assume what is happening is that the deflection of the rudder when sailing is enough to crack the weld at the top of the skeg. charlie

  6. Jean-Claude

    The same situation append to my Tanton hull, I replace the seek for a longer one protruding 8 inch inside the hull and welded on the rib frame, now I do not have any issue with the seek leak we had to cut a opening in the cotpit to perform the weld inside the skirt.
    For aluminum hull antifaling I use the same as Dashew (Amercoat by PPG) use with 5 barrier coat of epoxy from the same maker PPG wit out any issue on the hull and no scrubbing required . My fellow friend French sailor use Interlux for aluminum and the hull was clean after one season in the south.

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