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The Prop-er Thing To Do - August 16, 2002

By The Ithaka - Published August 16, 2002 - Viewed 554 times

The Prop-er Thing To Do
Nuinudup, San Blas Islands, Kuna Yala Panama, Central America 09o 33.799’ North 078o 51.608’ West

 

August 16, 2002
By Douglas Bernon  More articles by this author

 

 

Your boat may be tricked out with electric winches, carbon-fiber masts, 80-gallon-an-hour watermakers, 25,000-BTU air conditioning, full-color integrated radar/GPS chart plotters, plus every high-tech, mega-giga-gizmo known to creation, but if you don’t got a dinghy to get around in, you’re just toast. Everyone out here relies on them totally; your dink is your workhorse, limo, motor scooter, escape pod, ticket to the reef, pick-up truck, and the lifeblood of social experience in any anchorage. Families with kids soon conclude they need at least two dinks, and couples without kids often wish they had that many as well. Sure, sometimes you swim over to a friend’s boat, but mostly you drive the dink. So, when the dinghy motor’s not working, even though you can still get from here to there by rowing (which soft-bottom inflatables barely tolerate), it’s mighty slow going; you don’t go as far, you don’t go as fast, you don’t go in risky weather, a strong current or at night. In questionable moments, when it’s row-only time, you don’t tend to go at all. See where all this is leading?

photo courtesy of Marty Baker
Kuna huts dot the little cays of the isolated San Blas islands.

Edwin Sherman’s Outboard Engines: Maintenance, Troubleshooting and Repair-Be Your Own Outboard Mechanic, a first-rate diagnostic and how-to manual, is our Outboard Bible. Sherman’s a terrific teacher, and it’s easy to make sense of what he’s talking about, even if you know as little as I do. My only beef is that he and all the other how-to authors always tell you the right way to do stuff, and I’d place my money on ol’ Ed, that he could give Scotty a pretty good race for reinvigorating antimatter-propulsion systems, even if all he had on hand was bubble gum and chicken wire. But Ed, m’man, I just know you’re hoarding those "Now-kids-don’t-try-this-at-home" fix-it-on-the-spot secrets so you don’t have to sweat law suits and stuff. Sure. Sure. ABYC standards are just ducky, but out here in the real cruising hinterlands, when it comes to do-it-now-with-whatever-you-got-on-hand repairs, those standards are as useful as a handshake from your insurance company. Sometimes, the wrong way is the only way. You gotta make it up as you go.

The challenges of the cruising life require a strong dinghy with a reliable outboard. (Mural from Nargana, San Blas)
In general, how-to-books assume you have access to basic and esoteric supplies, an infinite set of tools, brand-specific replacement parts, and a stable platform on which to work, which for cruisers is wishful thinking on all counts. I’d like somebody to come out with a book that include a series of tips on how to fix stuff with only baling wire, Elmer’s glue, and fish scales. Take, for instance, dinghy propeller shafts. Props fit onto a shaft, hug it closely, and spin around, pushing water one way and you the other. What keeps the prop from sitting still while the shaft turns wildly is the fact that it’s snug against the shaft, and held in place, in part, by a sacrificial pin that gives way if you hit something. This is a pretty clever idea actually, because it protects everything, and if the pin goes, you just fiddle with the prop and pop in another sheer pin.

A picture of our first attempt at repairing our prop: showing the inner bronze casing, surrounded by the evil rubber and filled with too thin a layer of epoxy—a mistake that won’t be made in the future.
Technological progress, however, is often the archenemy of sound-and-simple, and this time it’s really buggered the moose. In recent years many outboard manufacturers have kissed sheer pins good-bye in favor of a cylindrical hub made of vulcanized rubber with splines (a kind of multiple tongue-and-groove pattern that mates with a complimentarily designed shaft). Sounds great in theory. But inevitably the rubber comes loose, or gets all soft and wiggly, or disintegrates altogether—proving again the warnings we got in high school sex education lectures. Anyhow, after your vulcanized rubber bites the dust, you can race your throttle till the cows come home, but all you’re left with is the outboard equivalent of one crazed hamster jacked on a load of high-test coke, sprinting toward death on its treadmill.

The rubber-hub system is a perfect example of product made to break, an unnecessary, potentially dangerous, and predictable failure merely awaiting an inopportune moment in your already maintenance-filled life. When that little sucker gives way, usually you can’t repair it properly, or quickly, and to read the how-to manuals you’d think you either need to buy a new prop, or in the felicitous jargon of the industry, you gotta get "rehubbed." I imagine one prop commiserating with another: "Yeah, man, I hit some hard times, and now I’m in rehub."

Frank and Lynda from Simba
Our prop gave way the other day when Bernadette was in the dinghy. Ithaka was anchored in the middle of nowhere, between two uninhabited cays (Ukupsuit and Kalugir Tupu), and around us were the beautiful reefy shallows that make the waters of the San Blas so turquoise. Nearby, our friends Frank and Lynda were anchored on Simba. Bernadette and Lynda had taken off in our dinghy to explore, and according to my beloved, the shaft suddenly started spinning without communicating to the prop. They were more than three miles from Ithaka. Not ideal, but not the end of the world either, luckily. Bernadette found she could keep the prop rotating very slowly in lowest idle, and with that littlest bit of propulsion, she and Lynda were able to slowly row the chubby inflatable back to Ithaka. Against a strong current this could have become a serious problem.

Being reasonable planners, we had a spare prop at the ready when our hub disintegrated. I’d bought it from the Nissan dealer when we’d bought the motor—a little over two years ago—and foolishly I figured it would fit. But of course it didn’t, and in the middle of the San Blas Islands, we found the spare to be useless.

Frank came over, and together we tried to figure a solution.

"Screw it," declared My Personal Commodore. At first I thought this an uncharacteristically indelicate comment from someone so proper, but Bernadette meant it literally. She thought we should set some screws through the prop into the bronze sleeve that fits onto the shaft. Being guys, we couldn’t accept a girl’s advice immediately. No, we decided. That was too radical, and we’d run the risk of scoring and stripping the shaft, causing permanent damage. Instead, as a first step, Frank and I decided to reinforce what rubber was left with two-part epoxy. We removed as much as we could of the softened rubber, grooved some channels in it to accept the epoxy, then filled it and let it dry for a day. Finally, we put the whole rig back together and engaged the prop.

This is either Bernadette ready to vent her frustration on one of the manufacturers of these new-fangled props, or it’s a mola by Lisa Harris depicting a biblical scene of Isaac and Jacob.
To paraphrase Yeats on outboards, the center wouldn’t hold. Bernadette had the grace not to say, "I told you so," which made it easier to follow her plan, which was better than ours to start with. We drilled holes and tapped them, then inserted three machine bolts as set screws, going in only as far as the bronze sleeve that fits over the shaft. For the past month, it’s been holding fine, and on our next visit to the States we hope the outboard dealer will do the right thing and exchange our spare prop for one of the correct size.

But our repair is temporary, and not ideal, and when it fails I’ll follow the advice offered by Yarif, a long-time cruiser on an Israeli boat named Carne. We met him a few days after we made our so-far-successful prop repair. Yarif told me that after several rubber-hubbed props had stranded him on distant reefs, he came up with a more radical and, so far, permanent solution. "I don’t trust these new props at all," he said. "Your set screws will buy you a couple of years. But here’s the only thing to do to really fix the problem. The moment you get home from the store with a brand new prop, gouge out every molecule of that stinking rubber and replace it with inflexible two-part epoxy. It’s the only way to go. I’ve done that on mine and haven’t had a problem in years." I think of him as Yarif McGyverstein.

No doubt Yarif’s system would never gain approval from the ABYC or the Consumer Product Safety Commission, but keeping it in mind may help get a few people back on the road—after they row themselves the three miles back to the mother ship.

The fishermen present Douglas with their dilemma
Yesterday, as Bernadette and I were getting our diving gear ready to dinghy to the reefs to go spear fishing, a Kuna ulu full of fisherman whom we’d met the day before paddled up to Ithaka. When we’d first met them, they were under power, their ulu full of fish, octopus, squid, conch, crabs and lobster, and we’d happily lightened their load, buying crab and fish. Now, here they were paddling, one man waving their prop in the air. Sure enough, they had the exact same problem as we’d had... "Little do they know, they’ve come to the prop doctor himself," said Bernadette, as we examined and nodded. The rubber hub on the Kunas’ shaft had given way some time ago. As a repair, they’d drilled several holes—11, to be precise—and inserted what amounted to poorly-fixed set screws (some as large as 3/8"). But all of them had slipped away, vibrated free, sheered, rusted out, or for some other reason just skipped town. I radioed my partner in prop crime, Frank on Simba, whom I knew would enjoy helping these guys as much as I would. We sent the fishermen off to fish and went to work on the project. From our grab bags, Frank and I found several bolts that were fairly close to some of the holes. We drilled out three that were roughly 120 degrees apart, tapped them for our bolts and screwed them down with a hope, a prayer, and some Loc-tite, a chemical that hardens like glue in grooves and stalls things from vibrating loose before nightfall.

A close-up of the Kunas’ problem prop, showing their many repairs
After several hours of work, Frank and I motored off to find their ulu, which was a mile or so away at the reef. We returned their prop in the best working order it’s known in some time. The lead Kuna dropped it atop the fishing net in the center of the boat, next to several dozen good-sized yellow jacks and a dozen or so conchs. I figured he’d toss us a couple of fish and say thanks, but in fact, as the various guide books point out, and as others cruisers have told us, the Kuna don’t have a word for thanks. (Although they can be highly articulate with sentences like "Aga be imar uda moka?" Do you have a gift for me?) Noticing me eyeing the fish, the Kuna leader asked if we wanted to buy some. We declined. At first I was peeved. All this rubs against the sense of gratitude I expected, even craved. Frank and I talked about this as we motored back to our boats in the dinghy.

"I guess that’s more my problem than theirs," I said. "Maybe helping out should be such a regular part of the fabric of daily life, like breathing, that there’s no need to say thank you."

Douglas and Frank jump in the dink to return the repaired prop to the Kunas
"Maybe so," said Frank. Then he added, "But a fish wouldn’t have been so bad either." This is one of the things I love about Frank. He’s willing to spend endless amounts of his time to help anybody out, while maintaining a keen sense of the absurd. Frank’s a walking how-to book of technical information—in fact, he chaired the international commission that developed the NMEA standards, and he’s personally designed many of the marine instruments we all rely on. But he’s far more creative than any how-to book, because he loves to use whatever’s at hand. But most importantly, he’s one of the most generous people I’ve ever met. Next week, Simba and Ithaka will be heading up the coast to Linton and Portobello, and then going our separate ways. I’ll miss him enormously and hope one day he’ll read this and see it for what is: a prop-er thank you.




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