Overpowered Trawler???

Discussion in 'Diesel Engines' started by pha7env, Jun 10, 2012.

  1. pha7env
    Joined: Aug 2011
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    Location: Lake Dannelly, Alabama River

    pha7env Junior Member

    I am looking at a 1991 Charles Neville, Steel Displacement Trawler. It is 52'LWL, 95,000#, drafting 5.5. The best i can figure the hull speed is just over 9kts and it should take less than 200HP to take her over that. For some reason, the boat was powered with not one, but two 6125 luggers that have a continuous duty rating of 380 hp. Can you run this boat at low enough speeds to get any economy out of her?
     
  2. Aliboy
    Joined: May 2011
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    Location: New Zealand

    Aliboy Junior Member

    Around 15 - 20lph at 9knts I would expect. Say ~2NM per USG with a clean bottom. Does seem a bit strange to have all that hp, but in a heavy sea it would probably fell quite welcome.
     
  3. pha7env
    Joined: Aug 2011
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    Location: Lake Dannelly, Alabama River

    pha7env Junior Member

    I actually talked with Charles Neville, the designer. He designed the boat for the owner of Florida Bay Trawlers as his personal boat. Diesel was cheap and the owner want to get the boat to go 14kts. Charles said the boat was really a well built boat, but, at the owners request, the aft section of the hull wall flattened for for more post displacement speed. That said, it will do 14kts but it takes a minimum of 40gph to do so. I then spoke with Bon Senter of Lugger figured that the boat would idle over 6 knots which is too fast for what i want, and at 9 knots, the engines would only be running at around 20% which could be an underloading issue. Also, Mr. Neville said that the flat aft was not designed for heavy following seas and may get quite squirrely at slow speeds but should be ok at higher power as the boat was designed for fair weather. That pretty much sealed her fate with us. 200k for a coastal boat is not in my budget. If it were around 80 i would sure consider, but just can't afford both an inefficient boat and expensive boat!
     
  4. daiquiri
    Joined: May 2004
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    Location: Italy (Garda Lake) and Croatia (Istria)

    daiquiri Engineering and Design

    This sounds like a case for that old thread http://www.boatdesign.net/forums/boat-design/client-always-right-31899.html . There are times when it is much better, if possible, to talk the customer away from a foolish idea, than to follow him. I believe Mr. Neville, who has a really nice portfolio of designed and built boats, and hence has a required authority, in this case should have been more insistent with the client and tell him - look, that's a folly you're asking me to do. All the logical arguments would be on his side, and an intelligent client would understand. If one doesn't have such a big name (my case, but I'm working on that ;) ), then most of the times he ends up with just compromising (but essentially complying) to client's requests.

    Now, about bout that boat. In order to make it possible for an already heavy boat to reach 14 kts, it was heavily overpowered, with the relative additional weight penalty. My calculations, with some non-verified assumptions, optimistically indicate roughly around 600-650 HP the power necessary to reach that speed, with boat data taken from here: http://www.yachtworld.com/core/list...rency=EUR&access=Public&listing_id=64851&url= . With more due caution, it is probably closer to 700 HP - a value not too far from what you claim is the total power of the installed engines.

    But going that way is not a sound choice, imho. It requires an overdimensioning of everything, from diesel tanks, to engine mounts, to the drivetrain, to the engine room space, ventilation - everything. which means even more weight penalty and a drivetrain (transmission, propeller) setup which necessarily gives a bad (too high) trawling speed when running at idle. Possibly even prop cavitation and excessive vibrations at full throttle (depending on underwater design particulars). And the fuel consumption will be so high that you will seldom ever (read: never) go at full speed, so all the above mentioned efforts for nothing.

    If I were you, I would stay away from that boat, it's a wave-maker with huge maintenance and fuel costs. But I am not you and it's your money, so your ultimate decision.

    Cheers
     
  5. pha7env
    Joined: Aug 2011
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    Location: Lake Dannelly, Alabama River

    pha7env Junior Member

    Daiquiri, your assumptions and calculations are exactly what we came up with. Mr. Neville did establish with me that he explained to the Customer, who was, and is a boatyard owner and yacht (Florida Bay Coasters) Builder. But, fuel was cheap and busy people think they must go fast. As for me and mine, the joy is in the journey! Unfortunately for me, I love steel and the boat (or boats) that fit my needs do not fit my wallet. So for now we will be buying an older boat, like a Hatteras LRC until i can convince the Admiral to let me refit an steel fishing vessel. Meanwhile i will learn what it takes to have an effecient, affordable, very seaworthy boat in hopes of getting there one day to go anywhere, almost anytime! Thanks for the input. It validates the hours i put into gathering similar results! Robert
     
  6. mydauphin
    Joined: Apr 2007
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    mydauphin Senior Member

    Some thing happened with my boat. Buy it cheap, sell motors, replace with a single. Unless you can get a better somewhere else. It is the more is better syndrome. I have seem boats with 1000 hp that really should have 300hp. People with money are always right, until they are wrong and they sell it.
     
  7. WestVanHan
    Joined: Aug 2009
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    WestVanHan Not a Senior Member

    Horses for courses:I have 1300 but very rarely use it,but the times I have used it all I was very glad that I had it there.

    But yes, 700 hp in a coastal "trawler" is overkill.
     
  8. pha7env
    Joined: Aug 2011
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    Location: Lake Dannelly, Alabama River

    pha7env Junior Member

    The idea would have been to use it to go further than coastal so it was not just the HP that killed it. It was also the aft section that was flattened on what was an awesome passagemaker style displacement rig. A side effect of flattening out the rear was that it left the props hanging naked underneath making it, to me, virtually useless. If it were really cheap, and being steel, we possibly rework that part and reset the wheels so as to be a more stable platform, even to the point centering one of those awesome engines and making it a single. But not for 200K.
     
  9. WestVanHan
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    WestVanHan Not a Senior Member

    Especially this one being kind of a mongrel and the economy in those parts being down it'll be tough to sell.

    How long has it been for sale? I'd suggest figuring out what your costs would be to convert it to what you need...then roll in and make an offer that suits you.
    If they laugh at you...just wait another 6 months.
    Many power boats have dropped by 30-50% the last couple years.

    To build that new with all those goodies would be 7 figures+.
     
  10. pha7env
    Joined: Aug 2011
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    Location: Lake Dannelly, Alabama River

    pha7env Junior Member

    The boat has not been on the market, at least with the current broker, but about 6 weeks. I have been scouring the market for 18 months and try to keep track of any trawler or passagemaker in that size range in this hemisphere. I really like the boat, and if cheap enough i could live with it for quite a while. They claim 1 gal/mile at 9kts. The desinger said that should i choose to run one engine at a time, that i should get around 2/nmg/mile. I could live with that for a while. And a I could do a direct engine swap for a reasonable amount. But then, even with stabilizers, there is the sea keeping issue. The bow and midsection are designed with a keep, but the rear was flattened to gain speed. If i have less than 100 in the boat, i can use it in the gulf, islands and loop for 4-5 years until the kids get out of college. Then, put a hot price on it and buy a more seaworthy boat for passagemaking. But reshaping the aft section correctly where is has a full keel to make it suitable for rough water will be more expensive than i want to think about. Possibly around 150K(a guess)
     
  11. FAST FRED
    Joined: Oct 2002
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    Location: Conn in summers , Ortona FL in winter , with big d

    FAST FRED Senior Member

    You should consider the value of the engine package.


    You night be able to advertise the engines and demonstrate how well they operate before selling them.

    Then a pair of realistic sized engines could be installed , with perhaps new props.

    A flow scan installed on the existing engines might give great insight as to power required for performance you are willing to pay for.

    Almost all cruisers will operate well below "hull speed" as it can save 2/3 in fuel burn.

    'SL x 1.34 is hull speed

    SL x .9 to 1.15 is long range cruise for cost limited folks.

    A factory rebuilt engine and tranny can save 1/2 to 2/3 over "marine" suppliers costs.

    FF
     
  12. pha7env
    Joined: Aug 2011
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    Location: Lake Dannelly, Alabama River

    pha7env Junior Member

    Fred, we have surely looked option. Those Luggers, even with a few thousand hours, are valuable engines and coveted by fisherman. Especially in the PNW. I believe we could do the engine deal for not to much added money. We are monitoring this boat while we wait for our property in Nebraska to close. If it stays on the market for a while, we might just make an offer! They say the boat gets 1nmpg/gal at 9 knots. ( is just under hull speed, so our guess is that it will use around 3/4 at 7.5. At that, it would get even better at 6kts. Although, with the driveline the way it is set up, the boat will idle at 6 which means i would have to run faster during parts of the day to keep the engines healthy. That would hurt the average but might be liveable until we were able to swap. We shall see. Wish it were in the US so i could go test it.
     
  13. Aliboy
    Joined: May 2011
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    Aliboy Junior Member

    Those fuel burn numbers don't sound that good. I run a 43ft Sportfisher with twin 330hp and get 2NMPG at 8 - 8.5knts (max efficient displacement speed). Although that boat is much (MUCH) heavier, it has more waterline length than mine and I would have expected significantly better than 1NMPG.
     
  14. Angélique
    Joined: Feb 2009
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    Location: Belgium ⇄ The Netherlands

    Angélique aka Angel (only by name)

    Besides the over power issue and the spoiled aft section. Is it safe to bring 55' boat that's on the market in Colombia to the US . . ? ? How would you know you're not importing "something" . . . ? ? ?

    Anyway, good luck !

    Cheers,
    Angel
     

  15. pha7env
    Joined: Aug 2011
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    Location: Lake Dannelly, Alabama River

    pha7env Junior Member

    I would have Colombian customs inspect and ask them what they recommend before purchase. And have a reinspect before i left. Also notify US customs about the purchase and go straight to them asap. I used to do some work in that field, and still have enough friends in high places to belay any problems. Could happen though!
     
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