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Old 05-02-2017, 07:28 PM   #14
Nomad Willy
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City: Concrete Washington State
Country: USA
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 16,147
First thing I would do is all the research I could afford time wise to know how much power my boat requires. I would find an engine that pushes my boat at the normal cruising speed using about 55 to 65% of its max power. Because of my good experience w them I'd see what Yukon Engines has in Ballard. Their main line is Isuzu and Mitsubishi. But they have other brands.

The first Yukon engine I saw was in 1972 in the Queen Charolette Is. I man I knew was building a boat to use in the BC fisheries patrol. It was a 6 cyl Klassen (now Yukon). They have been marineizing engines since before then mostly for the fishing industry. So they are basically industrial products and the've been servicing the fishing fleet in remote places in both Canada and Alaska. You can get on the VHF and have parts flown out to you on bush planes or use more common shipping but they are very good at that.

Most folks here seem to think you need service that completely attached to the originally purchased product but I think not. You need quick and good advice from the original source but there are mechanics everywhere so most service on the go would be provided by a shop or mechanic where you have the trouble. So the main service from the source of the engine should be parts and the knowledge and experience to get the right part to you wherever you are.

If you PM me I will tell you what engine suppliers to avoid. But if they had the right engine I'd still buy it from them .. but seek services elsewhere.

My engine searches were over 10 years ago so I'm out of the loop as to where to go and what brand to seek. As I've said earlier I think the most important thing to get right is an engine that is rated as close to the power requirement that you have. And the engine should cruise at less than 75% load and over 50% load. Perfect for a FD boat would be about exactly 4 1/2 hp per ton of displacement. But there are more easily driven FD boats that only need 3hp per ton and some that may need a tad over 5. W/O getting a degree in engineering the best learning tool is lots of observations of many boats and calculations that you can do to arrive at the power you need.
For your boat I'd start comparing the KK42 to the Nordhavn 46. I'm not sure but I'll bet 85 to 100hp would work well. Just an off the cuff guess but comparing what the N46 does w 100hp and comparing the resistance of both hulls w real world weights a lot could be learned.
Also read Voyaging Under Power and compare your boat w more similar boats. And then find other boats to compare with. Try to identify the overpowered boats and some dock talk won't hurt if you can stay objective. Lots of what you hear won't be but in time you'll be able to quickly identify the real stuff.

North Western Washington State USA
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