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Thread: Article I stumbled on, 16 Classic, Yanmar engine

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    Post Article I stumbled on, 16 Classic, Yanmar engine

    You're in your friend's new tender, a Donzi Classic 16, running toward shore from his anchored yacht at a comfortable 33 mph, when he casually mentions that the boat is out of gasoline. Before you have time to panic, he explains that that's because this boat doesn't run on gasoline. She's diesel-powered, which, he points out, means he doesn't have to carry gasoline onboard his yacht; he can fuel the Classic 16 right from his yacht's main diesel tanks.
    This boat is real, and so is her performance. In fact, she cruises at 33 mph and tops out well over 40 mph. She's proof that it's possible to get exciting performance in a sportboat without resorting to a gasoline engine. For in her engine compartment, where you'd normally find a five-liter V-8 taking up most of the space, there's a two-liter Yanmar four-cylinder diesel so narrow it looks lost. Two people could sit here, one on each side of the engine, and play cards on the valve cover. Obviously, service access is superb.

    There are other striking differences, not the least of which is weight. Of course, everyone knows diesel boats are heavier that gasoline-powered ones, right? Not here. In fact, at 2,580 pounds, the Yanmar-powered version is 259 pounds lighter than its gasoline cousin. The V-8 weighs 938 pounds, compared to the Yanmar's 679 pounds, both with MerCruiser Alpha One stern drives. That translates into 4.26 pounds/hp for the gasoline engine versus 5.43 pounds/hp for the diesel. The V-8 produces 220 hp or 44 hp/liter; the diesel, 125 hp or 62.5 hp/liter, thanks to turbocharging and aftercooling.

    Despite its modest size, however, the Yanmar isn't completely superior. A deficit of 95 hp takes a toll on performance. The V-8's top speed is 58.5 mph at 3950 rpm. However, fuel consumption favors the diesel. The V-8 burns 21.8 gph at WOT, delivering 2.7 mpg, while the diesel uses just 6.3 gph at WOT, generating 6.98 mpg. theoretically such outstanding fuel economy means the boat would have to carry less fuel-and therefore less weight- to achieve the same range, which might help narrow the difference in top speed. More important, at a typical cruising speed of 33 mph, the V-8, turning 3000 rpm, burns 9.9 gph and gets 3.4 mpg, while the Yanmar turns 3200 rpm, burns 3.2 gph, and generates 10.3 mpg. Put another way, the diesel Donzi can run at 33 mph for almost nine hours (294 miles) while the gasoline boat could manage only 2.9 hours and 96 miles. Since the diesel Donzi would make an ideal yacht tender, such range might be particularly useful if the yacht were in difficulty.

    Among other benefits of the diesel-powered version, its reduced weight makes it less sensitive to outdrive trim and its sound level is lower, in large part due to the intake silencing provided by the turbocharger. The diesel Donzi is also somewhat quicker out of the hole due to the Yanmar's prodigious low-end torque. Against this is the increased cost of going diesel - a bit under $7,000 more than the V-8. Clearly, the cheaper cost of diesel and the Yanmar's superior fuel efficiency and resale could go a long way toward ameliorating that difference.

    In the end, the choice of gasoline versus diesel power in a tender probably comes down as much to a particular owner's preference as practicality. But for a lot of yacht owners, the response to the pronouncement “out of gas” just might be, "Who cares?"

    Donzi Marine (941) 727-0622. Fax 941) 756-5638.
    Yanmar (847) 541-1900. Fax 847) 808-6968.
    Chuck Husk is a former president of Chris-Craft. He holds a master's license.
    DONZI CLASSIC 16 Specifications:

    LOA: 16'6"
    Beam: 6'11"
    Draft: 1'0" (drive up); 1'11" (drive down)
    Deadrise: 24 degrees
    Fuel capacity: 30 gal.
    Weight w/diesel (on certified scale): 2,580 lbs. w/ full fuel and gear
    Engine: Yanmar 4JH3-DTE
    Displacement: 121.7 cu in. (1995 cc)
    Continuous output: 116hp (85.3 kW)
    Maximum output: 125 hp (91.9 kW)
    Specific fuel consumption: 6.34 gph @ 3700 rpm
    Torque peak: 191.7 foot-pounds @ 3300 rpm
    ODU DAD and Damn Proud of it.

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    Unhappy

    Bryan,
    I sent this article from the Boating Mag. to Madpoddle for him to scan in and have it posted somewhere on this site a while back.

    Madpoddle,
    Did you ever get a chance to scan it?

    Craig
    Looped was born November 1966 18-103

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    No biggy Scott, I totally forgot about it until this post came up. I still feel bad about taking a half a year to get back to you with no info on the guy down your way selling his personal racing boats. Someone else sent me a reply on it too but I lost the email on who it was (Sean maybe?).
    Looped was born November 1966 18-103

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    Mastry in St. Pete had a 22 Classic with the Yanmar 300/Bravo. It ran 65mph out of the box. There was an article in both Hot Boat and Motor Boating a few years ago. I hear he had it running in the mid-70's after a drive height adjustment and some tweeks.

    (Can you say "trip to Key west on one tank"?)
    Never underestimate the power of persistance...

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    There was a 22 at Sarasota that had a Yanmar desiel in it. We were running about 70mph and he was having no trouble keeping up. It was weird seeing the big single exhaust port out the transom. --Brad

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    Very cool old article..............
    1972 16 OB - C16B-63 - "Surface Tension" Resto Project
    1974 16 OB - DMR16106017-B - "The Mule"

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    Only problem I see is the MPG figures. There is no way a 5.0 220 burns 10gph at 3k. My 454 only burns about 11. I would say the 305 burns 7 at that speed.
    Nick
    1994 22' Classic-454 B1 Red & white
    1981 13' Whaler sport(original owner)
    South Tampa Bay, FL "May I mamoo dogface to the banana patch?"

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    Agreed, cool concept. Similarly, some of the burn numbers looked flat wrong to me, based on other (fairly consistent) claims I've seen, but still.

    A more modern update: how about a Volvo D3-220 (209 propshaft hp) diesel in a 16 instead? As I recall, 727 pound complete package (motor, transom and duoprop drive), which should still be every bit of 200 lbs lighter than the smallblock 16. Performance should be almost identical to gas, at maybe 2/3 the fuel burn? Cost would be about $12k more I think.

    (Of course, the IDEAL engine for a 16 is known universally to be an inline 6 292, hopped up to somewhere between 220 and 300 hp. Superb maintenance access like was mentioned in the article above, lighter than a smallblock, no cost premium for a diesel motor, and you only need to buy one exhaust tip. My saying this, of course, is in no way whatsoever related to the fact that I happen to have two 292s for sale. Hey, did I mention that I have 2 292s for sale? )
    "I don't have time to get into it, but he went through a lot." -Pulp Fiction

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    I wonder if an in line 6 would even fit behind the back seat of a 16'.
    Maddy's Daddy
    L.I.,N.Y.

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    Based on my recent experience, I think it's almost identical to a big block for length. I'd thought it was longer, but the way they mount all the accessories (stacked on the front of a big block, offset on a 6) keeps the overall about the same.

    Of course, there's always transverse mounting...
    "I don't have time to get into it, but he went through a lot." -Pulp Fiction

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    TTT for smokers .............. 1
    1972 16 OB - C16B-63 - "Surface Tension" Resto Project
    1974 16 OB - DMR16106017-B - "The Mule"

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