Yanmar 4JH2 TE

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Daniel

Just ordered a 410 with Yanmar 4JH2 TE with 62 HP. 1.Does the boat come with a different propelor compared to a 410 with the standart 4JH2 E with 51 HP (pitch and/or size)? What is the propelor pitch ?Is the reduction ratio the same ? 2. What are the advantages of the larger engine ?
 
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Jim Bohart

think so, ck ref page, should be obvious

with a larger than needed engine the boat can dig a bigger hole in the water and your pocket. to make matters worse try putting on a bigger prop and digging some bigger holes. Larger engines are in vogue due to a strong economy built by folks who think that going faster is a matter of horsepower and throwing more money at a percieved "problem" is best, they understand little about physics or even care. The 51 hp is more than's needed for your displacement. larger engines burn more fuel, so your range is decreased and won't provide any significant advantage in speed I don't care what the wind/ current/ speed/ direction is; you in the same boat with 80 more or 100 more hp. aint going to get there faster than them; maybe less and spend more money doin it and have a worse time. It's called sailing and the fact is the joy of it should be in the gettin there, and not in arriving. The prop specs are listed in the reference section accessable from the home page, ya'll gotta start using these things thats why we provided them. JB
 
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carol donovan

you can save some money

Daniel: We upgraded the prop on our new H410 to a 3-blade Max feathering prop that can be adjusted in the water, and have the 51hp engine. It is more than adequate - at 2800 RPMs we use almost no fuel and cruise between 7-8.5 knots. At 3200 RPMs we consume fuel (3/4 gal/hr) but cruise at 9-9.5 knots (and we are towing a 9 foot RIB to boot). With the rack & pinion steering and 3-blade prop, the H410 stops and turns on a dime - no more than one boat length. We are liveaboards and have the boat pretty well loaded, including a genset and a 300 foot 5/16" proof coil primary anchor rode. Jim's right on - save yourself some money and go with the 51hp engine. /c s/v Twilight
 
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Daniel

Bigger is better?

Thanks for your answer, JB. 1. The 4JH2 TE was ordered for the boat by a previous purchoser, and I am very much aware of all aspects presented in your answer. 2. I have looked before at the Referance library. I have also looked at the Yanmar specifications and performance curves so I have a good idea about what I am getting...I am just trying to see if I can make any benefit from this situation. That is the reason I asked wether the boat comes in this case (having a 4JH2 TE engine) with a different pitch/reduction ratio propelor/gearbox (the referance table sais sais it's a 18X15 propelor and specifies no other when engine is different). This question is still open for me. 3. Knowing the correct pitch, the correct reduction ratio, and using Yanmar performance curves I will be able to calculate the optimal engine RPM to be used leveling velocity (knowing the boats body velocity which is around 8 knots) while minimizing fuel consumption. After doing the theoretic calculations I will be validating them in sea trials. 4. I am sailing my boats for years in a section of the mediteranian sea in which - unfortunatly - due to specific local winds and sea conditions, one must sometimes be motoring upwind for 24 to 30 hours, facing sailing alternative which will make any sailing lover - like myself and you - to a motorboat lover... 5. If you know wether there is a change in the propelor/gerbox specs., I will be glad to know.
 
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Jim Bohart

sorry got carried away

In my own B.S. the gear reduction ratio is 2.63 for both engines. The 50 has a 18x4 prop and the 62 is 18X15. Hope this helps. JB
 
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