Posts Tagged “Mechanical”

Nordhavn 47/52 Rudder Upper Bearing

Nordhavn 47/52 Rudder Upper Bearing

Boats are full of compromises, and advances in one dimension can bring problems in another. Nailing the full equation of longevity, strength, and serviceability often is truly challenging. A perfect example of this challenge is the Nordhavn 47 and 52 rudder upper bearings. The early members of the Nordhavn 47/52 line used fixed race ball…

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Cracker Boy Boat Works

Cracker Boy Boat Works

When we hauled out in Whangarie, New Zealand near the end of 2013, we didn’t expect to go more than 2.5 years before the next haulout. We finally lifted Dirona again at Cracker Boy Boat Works in West Palm Beach. In the nine days that followed, we cleaned and painted the bottom; re-applied Propspeed to…

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Balancing alternator outputs

Balancing alternator outputs

In our charging configuration, we parallel the house and start alternators to charge the house battery bank. Each alternator has its own individual Balmar Max Charge MC-624 regulator and we’ve been asked a few times if we balance the outputs using a product such as the Balmar Centerfielder.  This is one of those issues where…

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Fuel bugs

Fuel bugs

As we describe in Dirona fuel manifold, we choose to explicitly pump fuel from the appropriate bulk tank to the supply tank rather than gravity feed. This is a slightly more manual operating mode but has some advantages that we really like. The first advantage is that a leak in the supply system can put…

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Hot Rodding the Mastervolt Inverter

Hot Rodding the Mastervolt Inverter

Our Mastervolt MassCombi 24/4000-100 120V inverter works well and we generally like it but it has always seemed to go into thermal shutdown earlier than it should. The inverter is particularly vulnerable to thermal cut out when it’s more than 80F outside and the sun is shinning directly on the stern. The early thermal cutout…

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Changing the Hydraulic Actuator

Changing the Hydraulic Actuator

Stabilizers are used on ocean-going vessels to remove the discomfort of ocean swell. Generically they come in two broad forms, passive and active. Passive stabilizers are the metal fins that you might have seen hanging from outriggers on fishing trawlers. And, if you saw the movie The Perfect Storm, that was a passive stabilizer that…

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Oil Change at Sea

Oil Change at Sea

Earlier this week, we brought the boat up on the wing engine and shut down the main engine to change the oil. Normally we’d never do this, even though the chance of a problem is small, because in the unlikely event that a problem does occur, it would be a very big problem. (See To…

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To Change or Not to Change? That is the Question.

To Change or Not to Change? That is the Question.

Oil changes at sea get pretty close to a universal response from boaters I know. Everyone says loudly “DON’T DO IT.”  The risk of something going wrong when hundreds, if not a thousand miles, from shore is simply too high. And, with oil change intervals ranging between 250 and 375 hours, there typically is no…

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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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Electronics–Power Flex

Electronics–Power Flex

PassageMaker Magazine April, 2016: A Nordhavn owners’s remote cruising habits inspire a generator overhaul.

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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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