Converting ULDB into trawler

Discussion in 'Boat Design' started by ctmi, Nov 2, 2020.

  1. ctmi
    Joined: Nov 2017
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    ctmi Junior Member

    Looks like someone converted an ex racer into a very economical trawler.

    “ACHARNÉ IS THE BEST DAMN BOAT I’VE EVER HAD.” - Berthon International https://www.berthoninternational.com/berthon-blog/acharne/

    80 foot long but 2.6 GPH at 9-10 knots.

    I wanted to get the forum’s thoughts on this. Right out the gate, it looks like the made the keel significantly shorter since less RM is needed and and to improve roll inertia.

    Of course they have an even lighter weight to length ratio then when it was a sailboat. Not surprisingly, it pounds when going upwind. A lot.

    what modifications could you do to it to reduce pounding? I’ve thought of everything to a box keel, to water ballast bags in the front to weigh down the bow. Any thoughts?

    it’s an interesting concept but not for the faint of heart!

    Isaac
     
  2. upchurchmr
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    upchurchmr Senior Member

    Design a propper boat.
     
  3. ctmi
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    ctmi Junior Member

    ***Sigh*** That’s boat design forum for ya, immediate dismissal by men who build kayaks.


    Anyone want to use their noodles? Modification of existing watercraft to make improvements is firmly within the realm of boat design. Not all design work is clean sheet!
     
    Last edited: Nov 2, 2020
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  4. ctmi
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    ctmi Junior Member

    I would also note that the “improper” boat I linked was modified into a trawler on the east coast, went to South Africa on its own bottom and from there to all parts of the Indian Ocean while being featured in the documentary “Oceans without Limits”
     
  5. goodwilltoall
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    goodwilltoall Senior Member

    I think Bolger called his modified sharpie bows a "cut water bow", i know topaz is one of the sharpies this was designed into.
    He liked upswept bows but this could also be done on any flat footed bow where you scribe a center line lengthwise below the existing bow say 6" as an example then create a vee from current wide profile.
    Biggest trade off would be wider tacking angle
     
  6. jehardiman
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    jehardiman Senior Member

    At a DLR of 89 she's more a light weight than ULDB, and would most likely be passable as a motor yacht as long as you routed her as a sailboat. But as a trawler; nope, no way. She would never support the gear or the sea state.
    Make sure you understand the difference between a trawler, a boat that fishes with trawls; a troller, a boat that troll line fishes; and a motor yacht, which may be called "trawler" or "troller" by the unknowing because they look in profile like those vessels. The naval architecture requirements are very different between the three.
     
  7. DCockey
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    DCockey Senior Member

    For most recreational boaters "trawler" means a powerboat capable of long distance cruising with a somewhat "traditional" appearance and wheel located midships or futher forward. Usually they don't have a profile anything like commercial fishing trawler.
     
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  8. ctmi
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    ctmi Junior Member

    Ya I was talking about a recreational power boat I hate fishing
     
  9. ctmi
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    ctmi Junior Member


    That’s smart. That would be easily done too. Fill the void with very dense Expanding 8lb foam. Glass like crazy then 2001 paint and bottom paint and it’s done. Smart!
     
  10. jehardiman
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    jehardiman Senior Member

    "...they don't have a profile anything like a modern commercial fishing trawler". There, fixed it for you.
     
  11. DCockey
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    DCockey Senior Member

    Some "trawler" yachts have resembled US west coast trollers, but very few have resembled trawlers of any vintage which have large deck areas for handling nets and other gear.
     
  12. jehardiman
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    jehardiman Senior Member

  13. tlouth7
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    tlouth7 Senior Member

    Pounding would be reduced by moving weight out of the ends. Get the big engine further forward, and move the stuff that was put at the bow back towards the centre. Revisit the location of the tender and motorbike, there is plenty of room in front of the deckhouse. Ditch the "searchlight mast", nothing to do with slamming it just looks ugly.

    Accept that this hull is not designed to go directly into waves at speed.
     
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  14. Milehog
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    Milehog Clever Quip

    I am skeptical of the motion of all converted sailboats.
     

  15. Mr Efficiency
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    Mr Efficiency Senior Member

    What simple modification(s) to the hull, might mitigate that ? If any.
     
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