A look at what keeps Spindrift moving when the wind doesn’t
This one’s for my gear head friends out there.
People follow along for the sunsets and the dolphins, and I get it. But some of you want to know what’s under the floorboards. So here it is.
Spindrift’s main engine is a Yanmar 4JH 110CV — a turbocharged, intercooled, four-cylinder common rail diesel. The 4JH series has been the workhorse of serious bluewater boats for over thirty years. This newer common rail version is a step forward. Less noise, less vibration, cleaner exhaust, better fuel economy, and more torque than the older mechanically injected models. When common rail first showed up in marine diesels, a lot of cruisers were skeptical. Sensitive electronics, fuel quality becoming critical, the worry you’d need a dealer with a laptop to fix anything. Fair points. But Yanmar has refined the platform since those early days, and the 4JH110 has proven itself. I’ve been sailing with Yanmar diesels since I was eighteen years old, starting out as a deckhand. So when it came time to choose an engine for Spindrift, Yanmar was an easy call. The engine drives through a KMH4A hydraulic transmission, built by Kanzaki, a Yanmar subsidiary. A pairing that’s well matched and keeps the drivetrain in the family.
On the shaft is a 20-inch, four-blade B-PLUS FeatherStream propeller, right-hand rotation. It’s a feathering prop. When we’re sailing, the blades align with the water flow instead of dragging like a dinner plate. Less drag, more boat speed. Under power, the blades pitch into position and she digs in. Under sail, the feathering blades give us roughly a one-knot gain over a conventional three-blade fixed prop. That might not sound like much, but do the math on an Atlantic crossing which is about 2,800 nautical miles. At an average of 7 knots with a fixed prop, that’s roughly 17 days. At 8 knots with the FeatherStream, it’s closer to 15. That’s two days earlier to the dock and two days closer to that first Mount Gay rum and tonic with a lime. The prop also produces less prop walk than a conventional fixed prop, which matters on a boat without a bow thruster.
Between the engine and the ocean is the PSS Shaft Seal by PYI Inc. This is a mechanical face seal that keeps the Atlantic on the outside of the boat. No dripping stuffing box, no constant adjustment. We check it regularly because if it fails, that’s a bad day.
Steering is handled through a single rudder with a quadrant on the rudder stock. The rudder is hung over a shoe. When you turn the wheel, cables move the quadrant. When the NKE autopilot is driving, a hydraulic ram moves it instead. Simple, proven, and each system is independent of the other. Flanking the rudder to port and starboard are two dagger boards. This is a unique feature of the Boreal 56 design. They add tracking stability underway, which keeps the boat on course and eases the load on the autopilot considerably. Think of a surfboard with three fins. The autopilot itself is an NKE system, and we actually carry a redundant NKE pilot on board. On a boat where we hope to crosses oceans, the autopilot steers far more miles than any human does. If it fails, you’re hand-steering watches around the clock until you can fix it or make port. Having a backup isn’t overkill, it’s common sense.
For electrical power we carry a Fisher Panda i8000 generator which is a little diesel engine in its own right, tucked away in a sound shield. It charges the battery bank, runs the watermaker, air conditioning, and keeps systems alive on longer passages without firing up the Yanmar. The batteries are AGM glass mat which are again something simple and proven and you can find anywhere in the world. The bank holds about 780 amp hours total, with roughly half of that being usable capacity. Between the Panda, the main engine’s alternator, 1,200 watts of solar panels, and a Watt & Sea hydrogenerator, we have multiple ways to keep the bank topped off. I plan to get into the full electrical system in a future post.
The numbers. Spindrift can bunker 1,150 liters of diesel. At 2,000 RPMs she burns about 5.5 liters per hour and makes 7 knots. That is roughly 210 hours of motoring and a range of about 1,460 nautical miles. I haven’t fully tested these numbers at all, but, I also know that conditions like sea state, wind, and current can change them dramatically. But on paper, that’s a comfortable margin.
Maintenance and monitoring this boat is straightforward but non-negotiable. Oil and filter changes on schedule. Impeller swaps before they fail. Constant visits to the engine room while underway to make sure there are no leaks or overheating bits and peices. At anchor the PSS inspected, the belts checked, the raw water strainer cleaned. Every one of these systems was chosen for a long history of reliability and ease of repair. They were also selected because finding parts, in remote locations, should be easier, assuming, of course, we don’t have the spares on board. This is a necessity on an expedition-style sailboat.
Running a boat like this is not like owning a car where you never open the hood and don’t need to know how things work. On Spindrift, we are on our own, just Sarah and me. We need to be able to fix things. We need to understand how things work. We need to know where every wire and hose goes. And we need to carry spares. Lots of spares. We can not just pull over and call AAA Auto Service.
This is why everything on Spindrift needs to be simple and reliable. There are newer systems out there that might be greener, more efficient on paper, more cutting edge but if they can’t be understood, diagnosed, and repaired by us, in the middle of the night, with the tools on board, they don’t belong on this boat. We’re not against progress. But we’re not willing to bet our safety on technology that hasn’t been tested in extreme conditions and can’t be fixed without a technician and a Wi-Fi connection.
This is just the engine room. I plan to write more on Spindrift’s electrical system, navigational systems, and of course the sails and rigging. Stay tuned.
Fair winds from S/V Spindrift
S/V Spindrift 
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