David B Winter Engine Update Videos
Jeffrey with the HandiBot taking digital measurements of the damaged part of the crankshaft.
Before we dive into trip news and winter plans, I wanted to share a quick peek at what’s happening in the engine room. As you might expect with a nearly century-old diesel, every winter brings a project or two. This season handed us something a little bigger—and pretty interesting—so here’s the latest on what Jeffrey’s been up to. This winter has turned into a bit of an unexpected engine adventure on the David B. As we were returning from Alaska at the end of the season, we started noticing that the engine was making a new sound. At first, we thought it would be an easy fix at the dock, but upon first inspection we realized it was something bigger that might be the main bearings. But once we got a good look inside, the bearings looked great. So we kept digging and soon discovered a loose flange on the aft end of the crankshaft.
We pulled the flange off and sent it to a machine shop in Seattle. While a new flange is being made Jeffrey has been down in the engine room measuring, checking clearances, and getting ready for a careful in-place repair. Removing the whole crankshaft would require taking out pistons, rods, and even the massive flywheel, so machining it right where it sits is our best option.
To do that, we’re using a tiny milling machine called a HandiBot—basically a “pocket-sized” CNC milling machine. It can digitize the existing surface of the shaft and then help us re-cut it into a perfect, clean cylinder. It’s surprisingly precise for such a small tool, and it saves us from having to fully dismantle the engine.
We pulled the flange off and sent it to a machine shop in Seattle. While a new flange is being made Jeffrey has been down in the engine room measuring, checking clearances, and getting ready for a careful in-place repair. Removing the whole crankshaft would require taking out pistons, rods, and even the massive flywheel, so machining it right where it sits is our best option.
To do that, we’re using a tiny milling machine called a HandiBot—basically a “pocket-sized” CNC milling machine. It can digitize the existing surface of the shaft and then help us re-cut it into a perfect, clean cylinder. It’s surprisingly precise for such a small tool, and it saves us from having to fully dismantle the engine.
If all goes well, we’ll have the machining done in a few days after this newsletter goes out. We are on target for putting everything back together in a couple of weeks. As always, we’ve tackled harder projects than this one, and we’re feeling good about giving this last-of-its-kind engine the care it needs to be ready for another busy season in Alaska.
Sincerely,
Every year in the spring the David B gets to go to the boat spa, otherwise known as the boatyard. We feel that it’s an important maintenance task that keeps the boat in good shape. This year our tasks were pretty standard – bottom paint, clean the prop, and change the sacrificial anodes. We also had a once every four years survey.
