2460 bayliner hull stretching

Discussion in 'Stability' started by aitkenkingfish, Dec 6, 2013.

  1. aitkenkingfish
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    aitkenkingfish Junior Member

    Im considering stretching my 2460 bayliner hull its 8 foot beam 25 foot long. Im considering stretching the cockpit before converting to diesel. Ill be converting to a megatech 290 weight is 900 lbs dry mated to a Volvo duoprop drive. ill be stretching the hull 6 foot and im wanting to get an idea of the outcome since ill be adding more weight than the original 350 id like some more displacement.
     
  2. PAR
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    PAR Yacht Designer/Builder

    How do you propose to perform this stretching and why would you? A SBC weighs about 700 pounds fully dressed (about 550 without manifolds, pump, etc.), so your boat can tolerate a few hundreds extra pounds. Just ask one of your well fed friends to stay home (more beer for you). Simply put, IMO you haven't thought this through well enough yet. For example, with just some rough estimating, a 6' "lengthening" will probably add another full ton of displacement to a 2460.
     
  3. Stumble
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    Stumble Senior Member

    I am thinking it would be cheaper to sell this one, and buy a 30' bayliner instead.
     
  4. Mr Efficiency
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    Mr Efficiency Senior Member

    Why 6 feet ? That is a lot on a 25 footer, it will be a whole different animal altogether. The structural planning and execution would be not much less work than building another hull.
     
  5. PAR
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    PAR Yacht Designer/Builder

    Not to mention developing effective running surfaces.
     
  6. aitkenkingfish
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    aitkenkingfish Junior Member

    That won't work I'm looking to keep this Boat Trailerable. I don't want the extra highth and extra Beam.
     
  7. aitkenkingfish
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    aitkenkingfish Junior Member

    I would like a longer cockpit it could be a shorter stretch 2 to 4 feet. I have 2 2460 hulls Im planning on getting the graft out of the second hull from the transom forward.
     
  8. Stumble
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    Stumble Senior Member

    Sell what you have and buy what you want. There are plenty of 30' trailerable boats out there. What you are proposing is going to be a huge project, cost a fortune, and result in a boat no one wants.

    Making a boat longer is not as simple as just inserting a new section in the hull, it takes some real engineering in a boat like this.
     
  9. aitkenkingfish
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    aitkenkingfish Junior Member

    Sorry folks I must have not been specific in my original question. This has gone off on tangents of if I should. That question was never asked. I've done major restorations, hull up restorations On boats. I know monetary wise I wool never get back my investment that's not the point of this build. I'm planning on keeping this Boat for twenty years I'm converting to Diesel another investment I won't see a return on resale but I will see a return Fishing 3 days a week with long runs to the Fishing grounds. If we could stay on topic that would be great. This project is not what a lot of people would do that's probably why I can't find what I want on the market. I'm specifically interested in the Sea keeping when stretching a narrow hull by 6 feet or what the maximum stretch should be.
     
  10. Mr Efficiency
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    Mr Efficiency Senior Member

    Am I correct in thinking this hull alteration is purely to allow a somewhat heavier engine, or is there another motive, such as increasing the cockpit space ? If there is only the matter of the extra engine weight, and you are worried the boat will squat because of it, you could fit a bouyant pod to each side of the transom, the best way to do that is another question, but vastly easier than hacking up the boat, whatever way it is done.
     
  11. PAR
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    PAR Yacht Designer/Builder

    I'm reading from all this is he wants some displacement, which he really doesn't need for this engine upgrade and he want s a bigger cockpit.

    You can lengthen this hull, but because the hull tapers in plan and profile, the second hull isn't going to be much help, without cutting lots of pie wedges and finicky fitting of these bits and pieces. You'd save little effort over just extending the stern and fairing the bottom and topside to the new, narrower dimensions. A couple of feet will not hurt much, but once you approach 3 or more feet, the balance of the boat will likely need some adjustment. The fast way to extend the stern would be to use foam or light plywood (1/8" - 1/4") over some molds, to define the new shapes. You'd laminate a new hull shell and deck cap/liner over this.

    There are a few different 2450 deck caps and liners, which do you have, the Sunbridge? As to sea keeping changes, well this is a complex subject, with some subjective aspects to it. Generally a 15% stretch alters the longitudinal balance enough to want a close look at the "centers", running surfaces, loading, etc. Adding 6' is a 25% stretch and way past what would be considered reasonable without running some number and moving significant weights around to balance her up. The 2450 wouldn't be considered a "narrow hull". She has a 3:1 beam/length ratio which is pretty typical and about right for her length. At 27' she'd be a 3.37:1 beam/length ratio, which isn't that bad either. At this B/L ratio, she'd be more efficient underway and better in following seas than a typical 27' powerboat.
     
  12. aitkenkingfish
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    aitkenkingfish Junior Member

    Id like to gain fishing space in the cockpit area im looking to fish 6 adults to cut down on everyone's cost's we have long runs to the fishing grounds.
    the cockpit now is good for 4.
     
  13. PAR
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    PAR Yacht Designer/Builder

    Again, which configuration do you have (model and year)? Can you post a photo? It might be easier to enlarge the cockpit internally, then by adding to the boat's length. This would simply entail cutting up the liner and making the sole more accommodating, of course moving the helm and other elements in the process.
     
  14. Mr Efficiency
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    Mr Efficiency Senior Member

    Helluva job, you wouldn't need to be mad to attempt it, but it'd help !!! :D
     

  15. aitkenkingfish
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    aitkenkingfish Junior Member

    Hi par

    I'm tied up at my daughter's school today seeing up the aquarium store units I donated to the science department. I'll be able to grab pics and load them tomorrow.
     
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