Preparing your diesel engine for the upcoming season is a task not to be feared, as long as you follow a thorough checklist and take your time to ensure that each step is completed correctly. Here’s a guide to help you navigate the basics of the de-winterization process, and to ensure reliable performance and optimal engine health throughout the sailing season. 

1. Inspect the engine compartment. Start by looking for any signs of damage, leaks or corrosion that may have occurred during the winter months. Check all hoses, belts and connections for cracks, wear or deterioration, and replace any damaged components as needed.

2. Change the engine oil and filter. Drain the old engine oil and replace it with fresh, high-quality diesel-engine oil of the recommended grade. Also, replace the oil filter to ensure optimal engine performance and lubrication during the upcoming sailing season.

3. Check the fuel system. Look for signs of contamination or water buildup that may have occurred during storage. Drain any water or sediment from the fuel tank, and replace the fuel filters to ensure clean fuel flow to the engine.

4. Inspect the cooling system. Check the coolant level, and top off the coolant if necessary. Inspect hoses, clamps, and connections for leaks or damage. Ensure that the raw-water intake and cooling system are free from debris or blockages that could affect engine cooling.

5. Inspect and test the batteries. Check the condition of the batteries, and clean the terminals to ensure good electrical connections. Charge the batteries fully. Test them to ensure that they are holding a charge and are capable of starting the engine reliably.

6. Pre-lubricate the engine. Before starting the engine for the first time after winter storage, manually turn the crankshaft a few times using a wrench or socket. This helps circulate oil throughout the engine and prevents dry starts, reducing wear on engine components.

7. Start the engine and monitor it. Once everything is inspected, cleaned and prepared, start the engine, and let it run at idle for a few minutes to ensure proper oil circulation and fuel flow. Watch the engine gauges for abnormalities, and listen for unusual noises or vibrations that may indicate issues.

8. Do a test run. Take the boat out for a short ride to ensure that the engine is running smoothly and performing as expected. Monitor the engine temperature, oil pressure and other vital parameters, and address any issues immediately.

The post How To De-Winterize Your Diesel Engine appeared first on Cruising World.

Marine electric propulsion manufacturer ePropulsion has launched the eLite electric outboard motor, made for dinghies and the small-boat market. According to ePropulsion, the eLite represents a new era in clean, quiet and eco-friendly marine propulsion, with its focus on minimal maintenance and cutting-edge technology. The direct-drive motor and advanced design propeller deliver high efficiency with near-silent operation. 

“We are excited to start the year by introducing the eLite electric outboard motor, a game-changer in marine propulsion,” said Danny Tao, Co-founder and CEO of ePropulsion. “With its innovative features and commitment to sustainability, we believe the eLite will redefine the eco boating experience for enthusiasts worldwide.”

Designed to be the most compact and lightweight electric outboard in its class, the ePropulsion eLite 500W electric outboard is being marketed as an easy-to-use alternative to small internal combustion engines. Its Sport mode adds an additional 50 percent boost in power for challenging conditions, delivering a top speed of over five miles per hour. With multiple charging options, including 110/220V AC, 12V DC and solar with the use of optional ePropulsion converters, it can be fully charged in around four hours. For added capability and convenience, the eLite includes a USB-C output that allows users to charge and power other electrical devices. 

At just under three feet in length and weighing 14.7-pounds including the built-in battery, the eLite stores easily and the one-click quick-release bracket allows for installation and removal in a matter of seconds, according to the manufacturer. The tiller handle converts to a well-balanced carry handle. With multiple trim and tilt angles, adjustable steering resistance and shaft length, and a shallow-water mode, the eLite is completely customizable. Its Smart Battery Monitoring System (BMS) efficiently optimizes performance, carefully regulating battery level, temperature, and remaining state-of-charge all displayed on an ultra-simple interface, leading to extended range, a more energy-efficient operation and longer battery life. 

See the eLite electric motor in action:

The eLite is IP67 waterproof, and is constructed of aviation-grade aluminum alloy for lighter weight and greater durability. Its anti-ground auto kick-up feature protects the motor from accidental damage. Priced at just under $1,000, it is among the most affordable electric outboards in its class.

The post ePropulsion Touts “Game-Changing” New Electric Outboard appeared first on Cruising World.

A fracture in the pressurized shore-water line in my 50-foot schooner, Britannia, caused major flooding. It would have sunk her had I not managed to pump out the water ­quickly. I subsequently stripped and thoroughly cleaned five electric pumps, which worked again flawlessly. I also drained the engine oil and transmission oil and replaced them. Then, remarkably, the engine fired up immediately, as though nothing had happened.

Because the engine continued to start every time, I assumed that the starter motor was fine. During the hot summer months in Florida, we hardly visited the boat anyway, and rarely started the engine. This was a mistake. 

Over time, the starter began to turn the engine slower and slower, as though the dedicated battery was at the end of its five-year life. I installed a new battery but saw no change in the sluggish turnover, which was by then hardly sufficient to fire the ­engine at all. I also cleaned the heavy cable connections, but it made no difference. There was only one thing left to do: Remove the starter (Figure 1) and examine it. 

The thing about starter motors on heavy diesel engines in boats is this: They’re darn heavy. My engine is a Perkins 4.236 that weighs half a ton, and the starter is low down in the bowels of the bilge, secured with three very rusty three-eighths-inch nuts—one of which was almost impossible to reach with a wrench. After hanging upside down over the engine for half an hour, I finally got it off and hauled out the thing using the battery cable attached to the solenoid. It is 15 inches long and weighs 34 pounds. That’s the same weight as my number two CQR anchor.

Dismantling the Starter

There are two main parts to these normally reliable starters (see Figure 2). There is the solenoid (Figure 3), which throws a tiny pinion gear on the motor shaft into mesh with the flywheel attached to the crankshaft. The 10 teeth on the pinion gear are tapered, so they mesh smoothly with the flywheel teeth. It is called a Bendix Drive, after the inventor, Vincent Bendix, who patented it in 1915.

The other, much-larger part is the ­actual starter, containing the armature that spins the pinion gear (Figure 4) and turns the flywheel, thereby firing the engine. There could be numerous reasons why this was not happening, so ­everything on the starter needed looking at. I began with the solenoid.

Solenoid

After securing the starter firmly in the jaws of the big swivel vise in my garage, I removed the two screws holding the solenoid to the starter casing, along with the screw holding the electrical cable to the body. The solenoid still would not come away from the body, until I discovered it needed rotating a little to dislodge it from the groove it was locked in. It then almost removed itself, thanks to a large, heavy spring inside the solenoid that keeps the pinion disengaged until it’s electrically activated.

Removing the solenoid revealed the 1-inch-diameter piston (Figure 5), which throws the pinion gear forward about three-quarters of an inch in to mesh with the flywheel. There is actually nothing else inside the body of the solenoid. All the electrics are in the endcap.

I unscrewed the two small electrical terminals and the screws holding the endcap of the solenoid, and carefully pulled off the Bakelite cover. The contacts inside were dirty and badly pitted, telling me that a good electrical connection was no longer being made (Figure 6). The contacts can be removed from the endcap and cleaned. It’s best to clean electrical contacts with nonmetallic abrasives like Scotch-Brite or equivalent. Then I cleaned the inside of the endcap, greased the piston, and oiled the lever arm and pinion shaft with waterproof lithium grease. Finally, I put it all back together.

When the starter key is turned (or the button pressed on my boat), an electromagnetic field is created in the solenoid, causing the piston to retract against the spring and throw the pinon gear with great force in to mesh with the flywheel. Simultaneously, at the end of its travel, the piston also pushes the contacts together, transmitting the full voltage from the battery into the starter. This rotates the starter, which in turn rotates the engine, causing it to fire. On releasing the button, the starting current is discontinued to the solenoid, the pinion gear retracts, and the starter stops rotating.

After replacing the solenoid on the ­motor, it can be tested by applying a 12-volt positive voltage to the small terminal and the return on the body of the motor. The pinon gear should shoot forward on the shaft. Warning: Do not connect the heavy-duty battery wire to the solenoid during this test, or the starter will also rotate, creating significant counter-torque.

Starter Body

I next withdrew the two long setscrews from the rear of the starter casing, and removed the backing plate. This revealed an unbelievable mass of sludge and grime covering the four brushes and the commutator (this passes current from the brushes to the starter motor’s coils or windings). Some of it was so heavily encased that it refused to be dislodged, even after prodding with a screwdriver. Other parts dropped out in solid chunks. 

It was quite remarkable that the starter had even turned with so much water and conductive dirt inside. I washed out as much as possible with a strong jet of water from a hose—three times. I then sprayed the inside with degreasing liquid and dried it all out with a heat gun. 

Even these steps didn’t remove all the dirt, so I removed the armature to clean and inspect the windings. This was done by holding the casing in the vise and pulling out the armature. The brushes remained attached to the outer casing, and the commutator slid off them. 

The windings inside seemed quite clean, no doubt because of the dousing they had just received. I mounted the armature in the vise, with aluminum soft jaws installed, and then gently rotated a strip of 400-grit sandpaper around the commutator until it gleamed. The armature windings were then cleaned, and the end bearing and throw lever greased.

Before I could reinstall the armature, I first had to retract the four brushes so that the commutator would slide between them. On this motor, the complete brush assembly pivots, making the task easy using two small slivers of wood wedged between the arms on the brushes (Figure 7). When the armature was fully installed, I pulled out the bits of wood, and the brushes seated perfectly on the commutator. I then replaced the end plate, and the job was complete. [Editor’s note: The above procedure would benefit from a blow-down with compressed air, and then a washdown with a solvent such as brake cleaner, to remove all sanding dust, which contains copper, to prevent any possibility of a short across the windings.]

I decided to make a bench test of the operation of the starter, mounted securely in my vise. Using a car battery, I clipped a jumper cable to the larger positive solenoid terminal and the negative to the starter body. Nothing happened because the contacts inside the solenoid were open. 

Then, I held a second, thinner green wire to the terminal that normally carries the wire from the starter key or button (Figure 8). The motor pinion gear flew forward, and the motor spun furiously. On removal of the green wire, the motor stopped and the Bendix Drive retracted the pinion gear. I was sure that I heard the starter heave a sigh of relief, being free from all the foreign matter that was buried inside it.­ 

A final touch was to repaint the whole assembly black. I had built myself an almost new starter motor. 

It has performed perfectly on multiple starts, even when the battery was low, and it is a reassuring feeling to know that the engine will start at the push of a button.

Hailing from New Bern, North Carolina, Roger Hughes has been messing about on boats for half a century, as a professional captain, charterer, restorer, sailing instructor and happy imbiber. He recently completed a full restoration and extensive modification of a well-aged 50-foot ketch. Learn more at schooner-britannia.com.

Editor’s note: CW does not recommend the use of pressurized shore-water lines
on any boat. If you have one, water pressure should be off whenever you are not aboard.

The post How To Rebuild a Starter Motor appeared first on Cruising World.

Occasional grounding is an inevitable problem of navigating a yacht that draws 6 feet, 6 inches in the shallow Intracoastal Waterway. If you have a deep-draft boat like my 50-foot ­schooner, Britannia, and you happen to wander off the main channel, you can easily run aground. This does not normally cause damage for a long keel boat because the bottom is mostly soft black mud, but depending on how hard the boat goes on, it can be a quite a trial to refloat.

With any attempt to refloat, the propeller is whirling madly only a few feet from the muddy bottom. It is certain to disturb lots of silt and sludge, which then can be drawn into an ­engine-water-cooling intake.

Most freshwater-cooled marine diesel engines operate on the same principles: An impeller pump draws in cold seawater to cool the engine’s hot, fresh water through a heat exchanger; the residual warmed seawater is then pumped out the back of the boat, usually through the exhaust.

The large mesh filters fitted to most boats’ engine intakes will capture larger lumps of debris, such as seagrass and even small fish, but minute particles of sand and sludge can still pass through, clogging the seawater neoprene impeller and then working their way into the engine’s heat exchanger and cooling passageways. The first sign of this trouble is often a rise in the engine’s temperature, along with a reduction in revolutions and performance.

Stopped in Her Tracks

This exact scenario occurred when we were traversing a 20-mile section of the Intracoastal between Titusville and New Smyrna Beach, on Florida’s eastern coast, in spring 2022. 

Suffocating fumes suddenly filled the saloon, and I immediately cut the engine, then made an emergency stop by running aground in the soft, shallower side of the channel. There was no time to consider anchoring: I thought we were on fire.

All the hatches and portlights were flung open, and the breeze soon cleared the smoke to reveal a cracked fuel pipe on the Perkins 4.236 engine lift pump. This crack had been spraying diesel all over the hot engine, creating the thick, acrid smoke throughout the boat. For the first time in my long sailing career, I had to call for a tow. We went back to the Titusville mooring field, where we examined the fuel-line breakage.

I unscrewed the large primary engine filter and found the 2-inch-diameter wire gauze blocked on the outside—which is where any debris should be—but also completely solid on the inside, something I had never seen ­before. It was obvious that a considerable amount of muck had been sucked into the engine.

With the plate removed from the front of the Jabsco seawater pump, I could see, to my complete amazement, that the impeller vanes had disintegrated and vanished, leaving only the hub on the shaft. This must have happened when the primary filter become totally clogged and the impeller ran dry, shredding the vanes. 

There is only one place the broken bits can then go: into the bowels of the engine. No wonder it overheated; there was little or no raw-water circulation. 

The next day, I cleaned the filter and pipes, and fitted a new impeller, but it didn’t help with the overheating. We had to restrict the engine to only 1,300 rpm as we trudged back to Britannia’s marina berth, 15 miles south, at 3 knots. 

To further investigate, it seemed logical to follow the flow of seawater from the impeller to the next piece of equipment and then onward. The first place any broken impeller pieces could go from the raw-water pump is into the oil heat exchanger, right at the back of the engine—of course it would be there, wouldn’t it? 

I removed the water hose to the heat exchanger and poked a finger inside—and found soft rubber and dirt. This ­discovery meant removing the double-barreled oil cooler, which was no easy task with a bulkhead in the way. I finally managed to get it off the engine and, using long-nose pliers, I pulled out as many bits of ­impeller as I could. Then I back-flushed the twin pipes with water. 

The next path for the raw cooling water was to the engine heat exchanger, which was also partially blocked with tiny bits of impeller, and lots of sludge. This was when I concluded that I had to completely dismantle and clean all the seawater passageways in this big engine. 

Dismantling

All the parts of the cooling system had to come off, to be examined and cleaned. But this was easier said than done, because two floor beams had been positioned over the engine, and it was impossible to get a wrench on some of the engine fasteners. 

The beams had to come out, so I used my circular saw to make 45-degree cuts on each end, then removed the beams. Weeks later, after reassembling the ­engine, I glued a sliver of wood on one end of each beam to make up for the thickness of the saw cuts, then bolted the beams to the splice to secure them.

The most important item to clean was the engine’s large main heat exchanger, with its honeycomb of tiny tubes carrying the hot fresh water to where it is cooled by the flow of seawater—that is, when there is any.

To get at the exchanger, I first had to remove the intake manifold—to get at the nuts to remove the heavy cast-iron exhaust manifold—to then get at the nuts securing the heat-exchanger. It is at times like this when I would like to get my bruised knuckles around the necks of the people who built this boat.

Three hours later, I had the engine heat exchanger in my hands. I counted about 100 ⅛-inch-diameter pipes inside the honeycombed body, but only about 30 would actually pass water. The rest were blocked with sludge, which had passed right through the ­transmission heat exchanger. No wonder poor old “Perky” didn’t have any strength. It ­needed a ­multiple bypass operation. 

I bought a 24-inch-long ⅛-inch drill bit, and carefully rotated it by hand down every tube I could get to, extracting reams of dirt from each. But some of the tubes were so solidly ingrained that I had to drill them clean using an electric drill. This is called “rodding the tubes,” and it needs to be done carefully. If the tubes become fractured, fresh water and seawater will mix, and the expensive heat exchanger becomes useless. 

I then immersed the whole thing in a bath of Rydlyme Marine dissolving fluid, a descaling liquid that diesel engineers use to clean inaccessible parts of engines. After that, I pressure-washed the pipes until clean water flowed through both the seawater and freshwater tubes.

The engine heat exchanger distributes water to the front and back of the engine block, so I removed all the remaining water pipes, and it was clear that debris had permeated through the whole seawater system, including as far back as the exhaust elbow. I think this must have been building up for a long time, well before our recent grounding.

Another item to inspect was the ­thermostat, but it wasn’t where the engine manual said it was. I then found out that my so-called British engine was a “North American model,” and the thermostat was located under the large header tank at the front of the engine. When this tank was removed, the thermostat was there—or, rather, the great black blob of muck that was covering it. 

By now, things were completely out of hand, and I had bits of the motor all over my garage. In for a penny, in for a pound, I thought asI removed the freshwater pump to gain access to examine the inside of the block. To do this, I also had to remove the thermostat housing on top of it. 

All these heavy cast-iron pieces were bolted with rusty nuts and studs into the block, and had probably never been unscrewed in 45 years. Some were so welded up with rust that I needed a long socket handle, which I smacked with a hammer to break them loose. (These I threw away, then bought new fasteners.) 

I also had to cut many of the hoses and lever them off the pipes. I had no Perkins part numbers for them, so I took the old hoses to my local auto-parts store, where I rummaged through the many shapes in their stockroom for similar pipes. New gaskets cost $150.

Some of the water-hose clamps had ­actually snapped, leaving the pipes holding on by corrosion and simple friction. The most serious of these was a 4-inch clamp securing the exhaust elbow to the large muffler. This was broken, and the joint was literally held on by corrosion. If the pipe had parted, hot exhaust would have entered the engine bay and easily caused a fire.

The correct type of water clamps for pressurized engine pipes are the sort that have indentations where the worm drive engages in the continuous stainless band. The clamps with open slots are thinner and weaker, and liable to fail over time. I replaced 21 of these weaker clamps.

By now, the engine was looking ­completely naked, with hardly anything on either side or ends of the block. After cleaning everything with degreasing fluid, I spray-painted the block and all the parts with blue engine paint, and prepared for reassembly. I wanted my hard work to at least look good.

The engine-block freshwater drain taps were seized up and impossible to open. They had to be unscrewed from the block, dismantled and cleaned. Still, no water came out of the hole until I reamed it with a drill bit, releasing a torrent of filthy brown water. 

Clearly, the block also needed cleaning out, so I tipped all the remaining Rydlyme Marine fluid into the block and left it overnight, in hopes of dissolving much of the ingrained grime and silt.

Reassembly

After draining the dissolving fluid from the engine—fluid that, from the looks of it, had done an excellent job—I began the tedious task of reassembly. It had been a month, and I couldn’t quite remember which pipes went where. I felt like one of the king’s men, trying to put Humpty Dumpty together again. It was a good thing I had taken photographs before I started.

And, by the way, all of this happened in the height of the summer, with daily temperatures in the 90s, and sometimes over 100 degrees inside the boat. All I had for protection against the blistering heat was the boat’s air conditioning, which managed to keep the temperature around 80 degrees. Otherwise I would still be at it.

On the starboard side, first the engine heat exchanger was relocated, along with its four connecting hoses. One long metal pipe coiled around the back of the engine to the other side. 

Then came the bulky, heavy exhaust manifold, which had to be bolted with new hose clamps to its equally massive exhaust elbow. After that, I secured the inlet manifold to restore the starboard side of the motor.

On the port side, the all-important raw-water pump was rebolted in place with yet another new impeller.
I ​decided to fit a second flow filter directly after the impeller pump. This would catch all the bits of any future impeller failure.

I then primed all the pipes with water, from the seacock through both heat exchangers and the exhaust. This would ensure that circulation occurred the moment the engine fired up, instead of the impeller running dry for even a few seconds. The freshwater pump was ­reconnected to the front of the engine. 

Before refitting the thermostat ­housing, I filled the engine with fresh ­water, ensuring that water filled the ­cylinder head. I checked for leaks in the pipes and gaskets. Thankfully, there were only a few hose clamps to tighten.

Then the header tank was refitted and filled, the alternator reconnected, and the belt tensioned. The job was now ­complete—well, nearly.

I had drained all the oil out of the ­engine sump by reaching right down into the bottom of the engine and ­unscrewing the drain plug. It drained into the engine pan, which I sucked clean with my ­vacuum pump. I then replaced the plug with a 90-degree elbow and a pipe connected to a hand suction pump next to the engine, so changing the oil will now be much easier. I also changed the ­transmission oil, along with new fuel filters, and then bled the fuel system.

It was now nearing the moment of truth—to see whether the engine would start, and, much more important, remain at its nominal operating temperature of 196 degrees Fahrenheit. 

I opened the seacock and gingerly pressed the start button. After a few splutters, the engine fired up as though nothing had happened. Within seconds, there was 50 psi showing on the oil gauge. 

By now, things were completely out of hand, and I had bits of the motor all over my garage.

Water soon began pouring out of the exhaust pipe with a lot more volume than before—a good sign. It still took a few anxious minutes for the water ­temperature gauge to begin to move. I refilled the header tank with another pint or two of fresh water as it gurgled its way into every part of the engine. 

The gauge slowly rose to 196 degrees and then stopped as the new thermostat opened, allowing for full circulation of water throughout the engine. I engaged forward gear and slowly increased the engine speed to 2,000 rpm. With the mooring lines bar-tight, the temperature remained steady. 

Taking Britannia out for a longer trial run was next, and with her plowing along at 2,500 rpm, the engine temperature remained constant. 

This was a successful, but long and difficult, revitalization of a 45-year-old engine that had probably been slowly silting up for many years. It is actually a fine testament to these heavy old motors that it ran at all. 

I’m relieved that it’s over, and I have to say, I wish the engine builders and boatbuilders had given more thought to their customers who work on the boats. Many items could have been positioned for much easier access.

Britannia had been immobile since early May 2022. It was now mid-August. Being retired, I was able to work on her most days, but delays in parts ­delivery, repairs, weather and more all took their toll. My actual work log showed 130 hours.

I intend to be careful in the future to avoid groundings and, if I have one, to immediately check the water-inlet filters. I certainly don’t want a repeat of this hard labor, or the costs.

The post Well, Let’s Not Do That Again appeared first on Cruising World.

Confession: I have an irrational fear. Not of heavy weather, but rather of having salt water back-siphon into my vessel’s diesel engine. Weird, right? 

Actually, not so weird. On new diesel installations, I’ve found that a common cause of premature engine failure is exhaust-related. 

Thus, a decade or so ago, when I installed a brand-new Perkins M92B in our 43-foot ketch, Ganesh, I paid careful attention to its exhaust system. I not only repeatedly rubbed it with hundred-dollar bills, but I also consulted various marine engineers and exhaust experts, including “Diesel” Dan Durbin, formerly of Parts and Power on Tortola, the guy who wrote the excellent “Please Don’t Drown Me” technical paper for Northern Lights. 

I’m totally anal about my exhaust system. For example: I have a custom drain on my marine muffler (Centek Vernalift) so that I can empty it during severe gales, or at least monitor the water level during extreme weather or after a 360-degree roll. Not only that, but the large exhaust hoses going into and out of that Centek muffler are different sizes at different points to reduce back pressure. And, yes, I’ve physically tested the back pressure in my system to make sure it is within spec. 

Even better, I have a water-exhaust separator (also Centek) mounted high up in my engine room, a setup that allows the raw water to flow out independently of my exhaust fumes. That’s right—my exhaust gases exit through one through-hull, and my exhaust water through another. 

Why so complicated? Because I am a poor man who sails in rough water with empty pockets, and I need my exhaust system to be bulletproof. It is much harder for a hose without salt water to allow salt water to back up into your engine than it is for a hose that contains salt water. 

Notice I said “much harder” but not impossible? That’s because nothing is really impossible for a determined, ­malevolent water molecule—nothing.

Anyway, the good news is that my system has worked perfectly, often in extreme weather conditions, for more than a decade and 50,000-plus ocean miles. The littlest details of seamanship matter most. For example, I always check my engine’s fluids before cranking up, and I always check the raw-water flow after cranking up. Always. (Well, except once in 62 years.) 

Here’s a quick overview of marine exhaust basics: There are two types. The hot-exhaust type is excellent at not allowing any salt water to back up into the engine, but the whole system is red-hot and often inadvertently catches the boat on fire; so often, in fact, that hot exhausts aren’t allowed on certain charter boats. They are just too dangerous on passenger-carrying craft. Fire at sea can be almost instantly life-endangering. 

It is much harder for a hose without salt water to allow salt water to back up into your engine than it is for a hose that contains salt water.

Most sailboats have a wet-exhaust system where the raw (salt) water mixes with the exhaust gases just after the ­manifold, and the coolish water/exhaust gets pumped into a muffler where the force of the exiting exhaust fumes lifts them both up and overboard. 

The problem with a wet exhaust is that there is always the possibility of water backing up and getting into the head of the engine. This often results in catastrophic failure of the engine—and, as a bonus, mental breakdowns among the boat’s owners. 

Which brings us to two days ago. I was waiting for a crowd of Singaporean friends to come aboard to go island-­hopping with us. They were slightly delayed. I checked the fluids in my engine, carefully eyeballed it, cranked it up (it started perfectly), and immediately visually checked its raw-water output by leaning over the side of my vessel. The raw water was pumping overboard just fine. Oh, what a good boy am I.

I ran my engine for a couple of ­minutes to allow it to come up to temperature, and then shut it off. During that time, I heard a clink, which I thought was something rolling off the cockpit table onto the cockpit sole. I lazily searched around the cockpit for the fallen object but couldn’t find it. (Clue.) No biggie, right? 

Once everyone was aboard, I recranked my now-warm engine, but this time it did not fire up on first revolution. It cranked a bit. That was unusual. (Clue: Anything unusual is a clue.)

Hmm, I mused to myself, thinking I needed to file, sand and clean my battery cables to get rid of any building corrosion. I did not check my raw water because, hey, I’d just checked it four minutes ago. What could go wrong in such a short span of time?

Plenty.

In blissful ignorance, I yelled, “Cast off!” at my wife, Carolyn, on our bow. She dropped the mooring pennant. 

All my Singaporean guests were ­huddled in the cockpit, thrilled to be underway on such a primitive, wild, daring-do sea adventure. 

“Is this safe?” asked a fellow who had never been on such a life-endangering voyage. 

“Oh,” I smirked confidently, “after three circumnavigations, I think I can get you to that placid isle called Ubin a few hundred meters ahead.”

Yes, pride always cometh before the fall. 

I attempted to increase my throttle—and, to my amazement, my engine slowed. It was at this point that it occurred to my seldom-used little pea brain that I might have a problem worthy of my feeble attention. (Clue: All problems are worthy of a skipper’s attention.)

While I was scratching my head where my hair used to be, and wondering if I had a throttle linkage problem, all hell broke loose. Huge billows of thick, gray smoke started coming out of all the hatches, companionways and opening ports. Coughing people came rushing on deck, terror in their eyes. 

“Fire!” someone screamed. 

All this happened quickly, just as I ­realized my engine was losing rpm because there was no oxygen in my engine room, only smoke. 

We were on fire. 

Carolyn and my daughter, Roma Orion, bravely hopped below to grab fire extinguishers, but both came shooting right back out, coughing heavily and bleary-eyed. 

“Poison!” Carolyn screamed. “Deadly gas!”

The situation was deteriorating quickly. Our Singaporean friends were desperately attempting to wave down a passing supertanker, screaming to be taken off Ganesh before their imminent and inevitable deaths at the hands of ocean-intoxicated, thrill-seeking Westerners.

My reputation as a respected circumnavigator was plummeting fast. I now did what I always do in emergencies: I glued on a confident smile, as if I possessed intelligence. I took a deep breath and asked myself, What the hell is going on? 

I shut off my engine and ordered the crew to the foredeck (they were all coughing and tearing up from the poisonous fumes). Next, I opened all the hatches for maximum ventilation, shut off the main battery switch (by feel while holding my breath) and, back on deck, unrolled the genoa to gain steerage. 

Once the engine and battery switch were off, the emergency was over. Well, except for our crying, terrorized guests, many of whom have since purchased rural property far inland. One claims to throw up whenever he sees a seascape. “It was exactly like the Titanic!” he tells his therapist and anyone else who will listen.

What, exactly, had happened? In a word: corrosion. When I initially cranked up, everything was fine until the clink. This sound was the flange connection between my manifold and exhaust system breaking three of its four corroded bolts. The breakage permitted the heavy pipe connection to gape open. 

Once there was no exhaust pressure in my exhaust system, there was nothing to force the raw water out of my muffler. Hence, my entire exhaust system and large-diameter hoses filled with seawater. 

After I shut off the engine the first time, some salt water flowed into my engine, not overboard. That’s why the engine hesitated while cranking the second time. But I didn’t realize the significance; I was too busy cracking dirty jokes in Mandarin. 

Mistake No. 2 was failing to recheck my raw water visually. It wasn’t pumping overboard, and if I’d have checked it, I’d have never cast off. Again, my bad. 

Before Carolyn cast off the mooring pennant, we were already in trouble. I was just too dumb to realize it. Pressurized salt water was spraying down the entire engine compartment. This caused numerous wires in my engine room to short out and begin melting their insulation. All this burning plastic, of course, produced massive toxic fumes. 

Once we were back on the mooring, we aired out the boat, unloaded all the praying, happy-to-be-alive, we’ll-never-go-to-sea-again guests, and attempted to troubleshoot our problem. 

Troubleshooting, of course, requires intelligence—why I thought I should be involved, I have no idea. I put Carolyn to port and Roma Orion to starboard, and cranked up the engine. They were supposed to tell me if they saw any new smoke or any tiny drips of water. 

Roma was immediately drenched with salt water. From where? The raw-water ­injection riser after the manifold, where the raw water gets injected into the exhaust system to cool it. 

At this point—idiot of limited ­intelligence that I am—I figured that I fully understood what had just happened. The hose clamp or hose had failed where the raw water goes into the injection point, and it had squirted under pressure, setting off a chain reaction. 

Clever, me not. 

At 3 a.m. the following day, I sat up in my bunk and said, “Oh, darn!” At first light, I unwrapped the vision-blocking fireproofing from the exhaust flanges that connect the manifold to the exhaust system. That’s when I saw the large, angled gap between the two. Without exhaust pressure in the system to evacuate the raw water, my engine exhaust system had filled completely with salt water. When I shut off the engine for the second time—thinking the emergency was over—the natural rocking and pitching of the vessel allowed salt water to get back-splashed into my cylinder head.

I now did what I always do in emergencies: I glued on a confident smile and asked myself, What the hell is going on?

The evil, ever-focused water molecules had finally had their day. I’d been too ­myopic to think through all the ramifications of the squirting water. Thus, corrosive salt water had been trapped in the cylinders for 18 long hours before I managed to get it out, and to fire up my no-longer-so-new engine. 

How much damage did this salt water do? I don’t know. My engine currently starts fine. And runs OK. (Yes, I changed the oil a couple of times.) But, surely, having the engine flooded with salt water for almost a day didn’t help its compression, now or tomorrow. 

And do I have another $20,000 laying around for a new engine? Nope! I could barely afford the new exhaust gasket and my extra-large serving of crow.

Why write such a depressing sea yarn? Because, as the T-shirts say, “Poop happens.” Despite a lifetime of guarding against salt water getting into any of the numerous engines that I’ve installed, my ever-plotting nemesis finally won a round. 

 Cap’n Fatty and Carolyn are currently in Langkawi, Malaysia, slapping paint on their bottom. (Did that come out right?)

The post Exhausted In Singapore, For All the Wrong Reasons appeared first on Cruising World.

Last month I reviewed some of the reasons an engine or genset might not start. This month I’ll delve into reasons an engine might crank but not actually start.

When an inboard diesel cranks, several things happen. Air is drawn into the cylinder or combustion chamber via the air-intake manifold/filter, passing through intake valves as the piston is drawn down the cylinder, creating a vacuum. As the piston returns, the intake valve closes, pressurizing the air. On a common gas engine, the compression ratio is roughly 10-to-1, and the compressed air is mixed with fuel vapor. On a diesel engine, the compression ratio is much higher, roughly 20-to-1, and the fuel is not mixed with the air until after compression has occurred.

While a higher compression increases the thermal efficiency of an engine, in the case of a diesel, it’s mandatory. As the air is compressed, its temperature increases, and in the case of a diesel, it’s hot enough to ignite the fuel when it’s injected into the combustion chamber by the injection pump and injector. If a diesel’s compression is insufficient, the air will not be hot enough to ignite the fuel. For this reason, a conventional diesel smokes on startup; the combustion chamber is still relatively cold, inhibiting complete combustion, and that white smoke is minute droplets of unburned fuel. So, low compression can be a reason for difficult starting (or not at all). This can be caused by worn piston rings, sticking or improperly adjusted valves, or a starter that turns too slowly (between 150 and 250 rpm are required for a diesel engine to start). Malfunctioning glow plugs—either the plugs themselves or the solenoid that controls them—can also make for hard or no starting.

Another aspect of this is the injection of the fuel. For conventional pump-line-nozzle (i.e. non-electronic) injection systems, fuel passes from the tank to a primary coarser (usually 10 to 30 microns) filter, usually via rubber hose, often to a water separator with a clear bowl. From there it’s on to a low-pressure (or lift) pump, after which it flows into a steel line, where it then enters the finer (in the 2- to 7-micron range) secondary fuel filter. It’s then on to the high-pressure injection pump, and finally to the injectors, again via steel lines. In this sequence, the most common causes for failure are clogged filters, a defective lift pump or air in the lines.

Your primary fuel filter should be equipped with a vacuum gauge; without one you are essentially flying blind, with no way of knowing how hard your lift pump is working to draw fuel through that filter. So if you don’t have a vacuum gauge here, I strongly recommend you install one; it’s a valuable troubleshooting tool, and it will alert you when that filter should be replaced. If, while cranking, you observe the vacuum gauge climbing, there is a restriction somewhere between the lift pump and the filter; naturally, the element itself should be checked and changed if there is any doubt.

Read More: Monthly Maintenance

If the vacuum remains low, below roughly 3 inches of mercury, then move on. The vacuum gauge will not alert you to restrictions that happen after the lift pump, including the secondary filter. However, if you change that filter when you change the primary filter, it’s unlikely to be the culprit. Regarding filters, it’s worth noting that some lift pumps include their own integral filter or screen, which can become obstructed.

Air can make its way into a high-pressure fuel system several ways, but most often at primary filter housings, in tanks low on fuel, and in plumbing unions between the tank and lift pump. Air will be drawn in only where a vacuum is present, between the tank and the lift pump, so concentrate on inspecting those areas: At rest, they might leak some fuel. Make sure everything is tight. Then try bleeding the high-pressure system to purge any air that might be present.

Finally, on older engines, it is possible for the injection pump and injectors to wear out, and/or become fouled with carbon, respectively. If the engine has more than 3,000 or 4,000 hours on it, pump wear reaches a point where fuel pressure is low enough to prevent combustion. This is often preceded by easy cold starts, where fuel viscosity is higher, and hard hot starts, where fuel viscosity is lower. Also, if the injection pump uses an electric solenoid-type stop plunger, these can fail or become stuck. Some engines energize the plunger to run; others energize it to stop. That’s an easy fix and well worth checking.

Steve D’Antonio offers services for boat owners and buyers through Steve D’Antonio Marine Consulting (stevedmarineconsulting.com).

The post Troubleshooting a Sailboat’s Auxiliary Diesel Engine appeared first on Cruising World.

This story originally appeared on Sailing Totem.

Along part of the west coast of North America, hurricane season officially starts on May 15. That’s still just a date on the calendar; it’s unusual to worry about systems in the Sea of Cortez until sometime in August. Even so, we’re sailing north and hauling out next week.

Since learning at the beginning of the year that our engine had …issues, we have intended to get back to the Cabrales yard in Puerto Peñasco. It’s probably “just” a head gasket, but we wonder what other issues are looming after 8,00 hours of running it. It’s been reliable and we’re diligent with maintenance. But that’s a lot of transmission wear. And the seawater pump has recently started weeping. We believe a reliable engine is an important piece of safety gear on board, so it’s time for a Yanmar whisperer (if you know one, get in touch!). This could mean putting our engine into the back of a truck and driving it to San Diego; who knows. Expertise will help us determine if we’ll put money into our 76hp 4JH3-TE (turbo), or if we’ll start researching options to repower.

At a gut level we see this swinging towards a repower (and no, not even for a second contemplating engineless – in case you saw our April Fool’s Day posts on Facebook or Instagram). We would rather not repower further south in Mexico for a few reasons. Not because there aren’t good mechanics here. Actually, there are genius mechanics to be found! So, why the move?

First, we believe the process will be a lot easier with where we can drive new stuff over the border than shipping and importing it elsewhere. It’s only an hour to Arizona from there (Salvador swears you can do it in 45 minutes, we drive… more slowly!) And San Diego may be a good place to sell it for parts, if that’s the right decision.

Second, hurricane season isn’t THAT far off. Cabrales Boatyard is the only hardstand in the Sea of Cortez that is not impacted by hurricanes. Northerly wind events generated up in Four Corners, yes. These usually blow in the 30s, and we’ve seen 50 knots! That that’s not a hurricane. Over the years, historical tracks show tropical remnants that make it that far, and they have even less wind than the northers. Kansas has had more remnant hurricanes than Puerto Peñasco! If you want a safe place to leave your boat, this is it.

Third, that pandemic that’s on? Our family are all now eligible for vaccinations in north of the border. Why wait for our jabs when we could do it soon, as a number of other shipyard denizens have already done?

Fourth, we can visit friends and family so much more easily. Generous friends are again making a car they aren’t using available for us. Having wheels translates directly to quality time stateside to connect with people we love. We SINCERELY HOPE to be headed for remote islands in 2022, so those visits are extra precious. (Look out Castle clan, we are practicing our Chicago rummy!). Pictured here are my parents: known as Poppy and Plug to their grandchildren. Mum is in a residence for memory care, and after many months, Papa can finally visit her in person instead of through a pane of glass or a screen. She doesn’t know our names any more, but she KNOWS US, and it will be really nice to get some time with both of them.

Fifth, the prospect of time on the hard is making us look anew at other projects on Totem. While we refit in 2018 and 2019 with the intention of time in remote corners again (damn you, COVID!) as usual our spending was all on safety and reliability. This time, we’re looking at making a few aesthetic improvements. Totem is pretty scruffy, inside and out; while that’s not a big deal in the scheme of things, we’re all excited about a little spiffing up. I have a half-built workstation. There are two cabins with primer but no paint. There’s a stove on its last legs. Galley countertop wearing through. With help from the crew at Cabrales, we can affordably do a lot of sprucing up.

Finally, and far from the least driving our enthusiasm to get north—rejoining the excellent company of friends at the boatyard. Several of our bubble boats from 2020 are there, and others are coming. Our socializing has been very cautious during COVID, and we are REALLY READY for that to change!

The post Sailing Totem: Our Hurricane Season Plans appeared first on Cruising World.

Recently, a member of a forum in which I participate shared a plea for help with an engine that would not start: “When I try to turn it over, I get nothing.” Should you need similar assistance, get the terminology right. If you turn the key to the crank position, wherein the starter usually engages and the engine rotates, and you get no response, the engine “will not crank.” If you turn the key and the starter engages, it “cranks but will not start.” Most key switches have three positions: off, run and crank. The latter is spring-loaded, so it stays engaged only while you are turning it; when you let go, the key returns to the run position.

If it does not crank (i.e., it doesn’t even click when the key is turned to the start position), it’s a clear electrical problem. The culprit is usually the starter itself or the battery; the wiring leading to the starter (from the battery or key switch) also might be compromised. First, check and cycle the battery switch; these can fail and contacts can become oxidized if not used for long periods.

Next, turn the key switch to the run position: Do the instruments respond? If not, electrical power to the engine is somehow compromised; check all of the connections at the starter, both large and small, for any that might be loose or corroded, or where ring terminals are not properly crimped. And don’t forget to check the large DC negative cable where it is connected to the engine block, or in some cases to the starter directly.

Most engines have a button-type circuit breaker on the engine that protects the power supply to the instruments and key switch, including the starting circuit; if it trips, the instruments will not respond when the key is turned to run, and the engine will not crank. These breakers can be notoriously difficult to find on the engine because they are small (a little larger than an eraser) and sometimes painted the same color as the engine. Find out where yours is located. This circuit also might be protected by a fuse—again these can be hard to locate because they are rarely labeled.

If you have no power to the instruments and you can use a multimeter, check for voltage at the start battery; it should show roughly 12.4 to 12.6 volts at rest, with no load and no charger. If the charger is on, you should see something over 13.4 volts. If you do have power, move on to the starter’s large post, to which the large red cable is connected. You should see roughly the same voltage there; if there is no voltage, that’s the problem: A battery connection is compromised, or the battery switch is off or defective.

If you do have power at the large post, the next test is the starter solenoid. Many engines use a yellow wire with a red stripe for the cranking circuit; it should indicate 12 volts when cranking only. If the key is turned to the crank position and you observe no power at this post, the key switch or its wiring is the issue.

While conducting these tests, it’s important to not only have a good ground for the multimeter, but it also should be the same ground the engine is using. Don’t connect the meter’s black lead directly to the battery; connect it where the large, black negative cable is attached to the engine block. Before taking any readings, confirm that this is a good ground by touching the red lead directly to the battery positive post or a known positive source. Doing so will ensure all of your subsequent meter readings are valid. There might be other causes, but the above are among the most common.

Glow plugs, if the engine is equipped with them, are usually actuated with a separate spring-loaded switch; however, some keys also might have a glow-plug position. In some cases, the engine will not crank unless the glow plugs are actuated (reminding you to use them); however, if this switch is compromised, it can prevent the engine from cranking, so it should be part of the troubleshooting process. Assuming the engine uses a pump-line-nozzle injection system (i.e., non-electronic) and it cranks but will not start, that’s almost certainly fuel-related. But it could be several other things, which I’ll discuss next month.

Steve D’Antonio offers services for boat owners and buyers through Steve D’Antonio Marine Consulting (stevedmarineconsulting.com).

The post Monthly Maintenance: What To Do When the Engine Won’t Start appeared first on Cruising World.

Engines are the boisterous beasts that sailors love to hate. We’ve known purists who pulled the noisemakers out; later they mostly pulled out their hair. Overwhelmingly sailors determine that this dependable power is essential, even if we officially refer to engines as “auxiliary.” Ours has put good service in, but this thrum from the heart of the boat is giving us heartburn at the moment.

Our 2020 was headed towards a high note in late December. With the whole family on board, we departed Puerto Peñasco on December 22 between strong northerly wind events. Jamie refers to it as the splash-and-dash. Possibly, it wasn’t a kind wakeup to our Yanmar.

The first leg was an overnight sail (odd how transits are typically referred to as a sail, even though we motored or motor-sailed almost the entire distance) to Puerto Don Juan, where we waited out a three-day blow and celebrated Christmas.

The next leg south was to Santa Rosalia; we left the first day possible. To be clear, we aren’t fans of cruising the Sea of Cortez in the wintertime. It is cold, and the opportunity isn’t so much to “cruise” as to “scoot between safe harbors when it’s not blowing stink.”

Getting south wasn’t just to get warm: it was in the hope our permits for passes to the awesome Revillagigedo islands would come through, and get there ASAP. Also called the Socorros, these islands 350 nm south of Cabo are a marine preserve biosphere of spectacular underwater life. Sharks – lots of sharks! Giant manta rays. Schools of pelagic fish (no fishing, that’s OK – we like to watch). Whales of the piscine and mammal species. How utterly awesome it would be to experience this as a family!

Arriving in Santa Rosalia in the wee hours of the morning, we anchored to wait for light to enter the harbor. In internet range again, we learned that our permits came through. The island would JUST fit into a detour from Baja to get Niall to his flight from Puerto Vallarta back to school, mid-January. Next weather window we’d continue to La Paz, hook up with friends there, and buddy boat to the Revs.

Jamie continues the tale from here.

First Signs of Engine Trouble

Just before hauling the anchor, I checked the engine and noticed the coolant expansion tank was weirdly dark. Removing it, I found it looked like the inside of a holding tank. Thumb-sized lumps of shiny oil floated in coolant stained dark from the ingress.

And the story goes:

• Engine type – Yanmar 4JH3-TE
  
• Engine hours – 8,313
  
• Engine status – questionable

Prior Cooling System Issues

Almost exactly a year ago, we experienced mild overheating while running the engine at anchor to make hot water. It may have been from snot-like little brown globs found in the coolant, which could have restricted flow sufficiently to cause a problem. With two diesel mechanics, all possible causes were removed and checked. The contamination source was never found. The freshwater cooling system was drained/ cleaned/ flushed (many times!)/ refilled, the engine worked normally for the rest of 2020. Even in a lower-mileage year, there were plenty of opportunities to put it to work in the often windless Sea of Cortez!

Sitting outside Santa Rosalia a year later, the ambiguity as gone. Clearly, there was a lot of oil in the coolant. The engine oil dipstick came up clean: no signs that coolant/freshwater contaminated the oil.

Testing Theories for Diagnosis

We took a berth at the marina to assess, and take next steps:

• Drained coolant and flushed six times with fresh water, the first two with a little dish soap to break down the oil inside.
  
• Ran the engine to circulate water during flushing. This did not introduce oil into the coolant again, but it was only low RPMs at the dock. However, the freshwater cooling loop pressurized enough to push water up into the coolant expansion tank, overflowing it until the engine was off and cooled.

Probable Cause: Head Gasket

By consensus of many and our own assessment, the cause has to be either a head gasket or cracked turbo – with gasket the almost certain culprit. It’s not the oil coolers (seawater cooled), or heat exchanger, etc.

RELATED: Sailboat Engine Replacement Options

It was a low few days of processing the possibilities, and considering the next steps. We had a lot of input from a lot of folks (you know who you are: thank you, especially Diesel Don, Salvador, and the LeLivres). The painfully cute foster boatyard kitten updates Jason sent through somehow came at just the right moments when a little lift was helpful.

Cruising is about letting go of fixed plans, and taking life one day at a time. It’s still hard to let go of missing the Revillagigedos. Our permit, secured in 2020, is just for this month. We’re told by park officials that the permit fees are jumping (no, skyrocketing! To the tune of hundreds of dollars per day for our family) for applications in 2021, so this might have been our only shot – I sure hope not. And we could wallow in that, and maybe I did a little; it was not great birthday news.

Now What?

At 8,313 hours, though diligently maintained/serviced we’ve decided that the engine needs thorough assessment. We need to identify the cause AND be certain that repairing it gains us a reliable engine for coral-strewn islands in remote corners of the Pacific.

There aren’t resources here in Santa Rosalia for a compression test. Nor is it the place to remove and resurface the head – open heart surgery for engines, as one friend put it – if we found it warped and causing the leak. Our current plan is to migrate between anchorages in range of Santa Rosalia for a month or so; the harbor offers relief from Northers, and eventually milder weather will enable a hop back to Puerto Peñasco. There we’ll probably remove the engine and get it somewhere for assessment – whether the outcome is a simple head gasket and general service or, gulp, shopping for a new engine. Well, it was going to be a slow year anyway!

This month we have an article coming out with 48°North about what wears out on a boat after extended cruising: ironically, it references our so-called iron genny as a major piece of gear that is still in service! Hopefully, we’ll have an addressable issue that means there are still a few thousand hours of service ahead. And if not, well, cruisers plans are always written in the sand at low tide, and we’ll write a new plan again.

The post Sailing Totem: Engine Heartache—Where DIY Diagnosis Ends appeared first on Cruising World.

If you’ve ever aligned your propeller shaft and ­engine, then you’ve handled the hardware that connects these two components together: the shaft coupling. While ­simple in form, couplings play a ­critical role in drivetrain reliability. If they are not ­properly installed, they can lead to vibration or worse — the ­separation of the shaft from the engine.

There are three primary types of couplings: straight, split and tapered, with the first two being the most common for smaller sailboat auxiliaries.

While straight-bore couplings are common, they lack the grip required for larger engines and props, which can place significant strain on the shaft-to-coupling interface. The challenge is getting the interference fit between shaft and coupling bore just right. If it’s too tight, driving the coupling onto the shaft may be very difficult, and if it gets stuck before it’s fully inserted, that can present a challenge. If it’s too loose, the shaft may begin to shift in the coupling with each forward-neutral-reverse shift evolution, which in turn will gall the key, allowing for more and more movement.

This scenario often ends with a sheared key and set screws, with the shaft and prop sliding out the shaft log, at which point they either screw their way into the ocean depths or strike — and jam — the rudder. If the shaft parts from the stuffing box altogether, a fire-hose-like geyser will erupt, after which the bilge pumps will be tested, and not in a good way. Installing a clamp ring on the shaft to prevent this scenario makes good sense as a safety backup. Better still, set up your shaft and coupling properly, and you’ll never have to test the clamp ring.

Split couplings are easily identified by their bifurcated design. While this coupling is really made up of one part, its aft end is divided into two sections that are clamped against the shaft using two or more machine screws. With this arrangement, the coupling can apply clamping action to the shaft. The split coupling offers one advantage over other coupling types, as it enables easy removal of the shaft by driving a pair of steel wedges or cold chisels into the gap between the two split halves.

Beyond this, there is no other benefit to using a split coupling, and I’d argue that rather than making it easy to remove, the primary mission of a coupling is to securely retain the shaft. Additionally, because it is split, and therefore moves or distorts each time a shaft is inserted or removed, the coupling face may not remain ­perpendicular to the shaft, which will affect the ability of the shaft to be aligned to the engine/transmission output coupling. In addition, it is possible to make a mistake during installation — for example, not torqueing pinch bolts in proper sequence, or pinching against a set screw — which leads to the coupler being off perpendicular, which can lead to a serious vibration. It’s worth reiterating, the only attribute of a split coupling is the ease of shaft removal.

Tapered couplings are ­popular on large horsepower applications and are the undisputed Cadillac of shaft-connection methods. Relying on the same principal used for the propeller-to-shaft interface, a cone-shaped hole in the coupling mates with a precisely machined cone-shaped male taper on the end of the prop shaft. Once the two are properly connected, and the retention nut tightened, they are very difficult to separate, which is exactly the goal. Separation, when intended, typically requires a ­puller — or a drift (a socket often works well) and longer coupling fasteners, which are used as jacking screws. Unlike the split coupling, a tapered shaft and coupling fit together the same way every time they’re assembled, so there’s no issue with retaining perpendicularity between the shaft and the coupling face, thereby ensuring proper alignment can be accomplished.

Next month, I’ll discuss coupling keys, keyways, pilot bushings, fastener and set screw selection, drift, roll, and taper pins.

Steve D’Antonio offers ­services for boat owners and buyers through Steve D’Antonio Marine Consulting.

The post Sailboat Propeller-Shaft Couplings appeared first on Cruising World.