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Old 05-30-2020, 08:45 AM   #1
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Wing get home engine on a single

I've recently inspected a boat equipped with get-home power - an auxiliary driving a hydraulic motor on the main shaft. No wing-folding-prop as is commonly seen these days.

I was wondering about those here who have used their wing engines because of failure of their single main, how many of these situations were caused by running gear failure (rope wrapped around prop, bent blade) or similar? Did anyone ever find it actually critical to have the separate wing prop?
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Old 05-30-2020, 09:22 AM   #2
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Get Home Engine

I have NOT had an actual occurrence with a get home engine, but I have given it a lot of thought.


On my Nordhavn 55 I had a completely separate get home engine, with its own prop. I believe if you were traveling in coastal waters then any decent get home engine would work. But then again so would not even having a get home engine.


On the other hand, if you were several hundred miles, or a couple of thousand miles, away from shore, then it always seemed to me that you want to cover ALL your bases, not just most of them. That means that the get home engine needs to work under virtually ALL circumstances, including those that involve damage to the prop, etc.


So, it depends on what you will be doing. If you plan on cruising the Americas, and that's an awful lot of cruising ground, then any get home engine would be great to have. Better than none at all certainly, although none at all might suffice. It would sure be nice to be able to move away from a rocky shore, or worse, at even a couple of knots, rather than be tossed up on said rocks. Or, have the ability to maintain at least some steerage in heavy seas while waiting for help.


The Nordhavn's get home engine was good for about 4.5 knots in calm seas, the only seas I ever tested the engine in. You could motor across the Pacific at that speed if you actually needed to. And, you could do it even if your main prop was fatally damaged, gone, or whatever.
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Old 05-30-2020, 09:46 AM   #3
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I have NOT had an actual occurrence with a get home engine, but I have given it a lot of thought.
So have I. First, I should make it clear that I have had both a single & twins on my last 10 boats and am presently driving a twin Yanmar boat. The question about having a wing engine was cleared up for me in Jim Leishman's latest video introduction on the new Nordhvn 41. Anyone wrestling withe the single or twin question should listen to what Leishman had to say. This guy has one hell of a lot of experience related to that question.


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Old 05-30-2020, 10:08 AM   #4
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In addition to a question about its usefulness in near shore waters, how much parasitic load does the hydraulic pump put on the prop shaft? Is there a clutch, which means probably very little. Or is the pump free wheeling which probably means some load but how much?

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Old 05-30-2020, 11:25 AM   #5
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Yes, clutched.

So Jim L. makes a comment about an alternate means to spin the main propellor not being satisfactory redundancy - hence the wing being on a separate shaft.

So back to my main question - how many here have come home on a wing due to failure/inability to use the main shaft? I would guess that most failures are due to engine problems. Anyone who sails long enough will have a fouled prop - you jump in with a mask and cut the fouling away - something I've unfortunately had to do several times as well.
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Old 05-30-2020, 11:38 AM   #6
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Many Willard 40s were produced with an auxiliary 3-phase electric motor as backup. Either belt or chain drive to main shaft that could be engaged in a pinch. I've been moderator of the Willard owners group for 20+ years and I know of no get-home scenarios. In fact, I know of a few owners who removed the behemoth motor as it required a 3-phase generator.

While I understand Jim Leishmans point about wing with separate shaft and prop, there is a significant tradeoff in maintenance and complexity. A hydraulic on-shaft system driven from a pump off a generator can sit fallow for years and be reliably pressed into service.

The above said, if I were doing some serious offshore passagemaking or circumnavigation, I would opt for a wing engine. But I'd also opt for a non-common rail main engine.
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Old 05-30-2020, 11:43 AM   #7
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Even if you can clear the fouling, there may be conditions where it's not safe to deal with it right away.
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Old 05-30-2020, 01:43 PM   #8
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Even if you can clear the fouling, there may be conditions where it's not safe to deal with it right away.

Murphy's Law almost guarantees it!


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