Posts Tagged “Mechanical”

Managing Fuel Economy

Managing Fuel Economy

We currently are underway on a 3,650nm non-stop run from St. Helena to Barbados. Prior to this passage, our longest non-stop run without fueling was 3,023nm from Dampier, Australia to Rodrigues, Mauritius. The current 3,650nm passage is at the very limit of Dirona’s range and we are, naturally, monitoring fuel economy closely to ensure we…

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Boat projects

Boat projects

We travelled directly from Rodrigues to Reunion, skipping Mauritius, mainly to spend more time enjoying Reunion’s incredible natural beauty. But we’ve also been taking advantage of being on a little less of a tight schedule to complete a few boat projects. Trip highlights from October 6th follow. Click any image for a larger view, or…

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Fuel economy and range

Fuel economy and range

You never know your boat’s real range until you start to make substantial ocean passages. Theoretical range in flat water with no current and little wind can be surprisingly optimistic so we probe the bounds conservatively.  The 3,023 nm Indian Ocean crossing from Dampier, Australia to Rodrigues, Mauritius is the furthest we have ever gone…

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Diesel engine underload

Diesel engine underload

We’ll be running our main engine at fairly low load for several weeks while we cross the Indian Ocean. Since this likely is below the manufacturer’s recommended range, we’ve been asked if we’re concerned about underloading the engine. It is true that manufactures have a preferred and fairly narrow range over which a diesel engine…

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Engine room cooling

Engine room cooling

Excess engine room temperatures are hard on the equipment and tough on the people. Engine room checks end up less detailed and, if you need to do emergency service, it can become a safety problem. We are all sufficiently motivated to want lower engine room temperatures but its actually not that easy. Engine room temperature…

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Maintenance log

Maintenance log

On our previous boat, we were (just barely) able to remember when all mechanical systems needed service as the hours mounted and time passed. But that system broke down when we got the current boat. There are far more systems, many of the intervals vary greatly, and when running offshore, up-to-date service is even more…

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A more flexible power system for Dirona

A more flexible power system for Dirona

A little over a year ago, we worked our way south from Fanning Island, Kiribati towards Nuku Hiva in the Marquesas Islands. We were on a long, fuel-constrained run where we would cover 2,600 nm without fueling. For most of the trip, we were heading up-current and into 30 kts of wind on the bow….

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A helping crane

A helping crane

Our next-door neighbors, Mark Mohler and Christine Guo of Nordhavn 62 Gray Matter, recently upgraded their davit to support hydraulic power-rotation. The base came off in two pieces, but is much easier to put back together at the shop. The downside is a heavy assembly: the upgraded base, with the power rotation transmission and motor,…

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Lubricating the bow roller

Lubricating the bow roller

After frequent anchoring, the bow roller bolts eventually would begin to jam and not turn easily. The anchor then would not freely deploy when released, and this also was causing wear on the stainless cheek plates on either side of the roller. The solution is to lubricate the bolt, but doing so requires removing the…

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Dirona Fuel Manifold

Dirona Fuel Manifold

Nordhavn delivers an unusually complete fuel manifold with far more flexibility than most production boats. In fact, the manifold is sufficiently complex that some new owners can find it difficult. More than once, I’ve heard of an owner accidentally closing the return path for the main engine or generator, leading to fuel leaks or, worse,…

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Battery thermal runaway

Battery thermal runaway

One of our eight Lifeline AGM GPL-8DL batteries recently went into thermal runaway, and we’ve had a few questions on the nature of the problem and why we chose to replace the full house battery bank. The lazarette smoke/CO alarm had gone off at 3am, and upon investigating we found a rotten egg smell (hydrogen…

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Replacing the main steering ram

Replacing the main steering ram

Steering is a great area to be picky about in overall mechanical system health. About three months back, we noticed a tiny amount of play at the spherical bearing that forms part of the rod end where the steering cylinder connects to the rudder. The play was minor, but spherical bearings should exhibit close to…

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Fuel for the crossing

Fuel for the crossing

Dirona carries 1735 gallons of diesel for the main engine: 835 gallons in each side tank and 65 gallons in the day tank. (We also have a 10-gallon supply tank for the auxiliary engine). Although 1735 gallons would have been fine for the roughly 2,000nm trip between San Francisco and Hawaii, we added 532 gallons…

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Wing engine hydrolock (under “Failures” in presentation Q&A)

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