Interesting things seen in a boatyard

Discussion in 'Boatbuilding' started by DogCavalry, Jun 6, 2021.

  1. DogCavalry
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    DogCavalry I aim to misbehave.

    Homer liking tuna is just reasonable. The comically extended transom looks like a reciped for bad handling at sea. 20210605_190254.jpg 20210605_190048.jpg
     
    Last edited: Jun 6, 2021
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  2. kapnD
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    kapnD Senior Member

    Could you elaborate on “bad handling at sea”?
    Extensions like this are pretty common on commercial boats, and are often accomplished economically with no changes to running gear. Apparently Homer would like to take home more tuna than he’s been able to carry previously.
    Similar extension projects I’m familiar with have improved the handling characteristics, increased crew comfort, and improved fuel efficiency, especially when returning to port heavily loaded.
     
  3. DogCavalry
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    DogCavalry I aim to misbehave.

    Two different boats...

    But the huge beaver tail with about a foot of draft will be in the air, or completely submerged in any sort of sea way. It won't take much pitching to slap that tail.
     
  4. DogCavalry
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    DogCavalry I aim to misbehave.

    20210620_113207.jpg 20210620_113227.jpg
    Not a lot of consensus on bulbous bow design.

    And I'm wondering what effect the extended hull will have on steering authority, now that props and rudders only a little aft of midships.
     
  5. Mr Efficiency
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    Mr Efficiency Senior Member

    The steering would not be that greatly affected, there isn't much profile in the water aft
     
  6. kapnD
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    kapnD Senior Member

    I’ve some experience on extended boats like that, there’s really no big negatives apparent.
    The vessel in question here looks to be a yacht converted to commercial fishing, so working deck space and fish storage would be needed.
    An added plus is that the running gear is well out of harms way when working over the stern.
     
  7. DogCavalry
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    DogCavalry I aim to misbehave.

    Actually, the structure on the beavertail extension is a garage for a classic jaguar convertible. The crane is for lifting jet skis and a boston whaler off the garage roof. I don't know how the jag will be disembarked. Ramp I guess. But since total draft at the new transom is only 12"/30cm, and freeboard is only 4"/10cm, I hope the garage door is like a submarine hatch. Unless total pitching on a 100'/30m can be kept to under 4" while at sea. Then a normal garage door should be fine.
     
  8. fallguy
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    fallguy Senior Member

    I dunno. Seems a bit sketchy to add a 25' swim platform for a car.

    But, like I said, I dunno.
     
  9. DogCavalry
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    DogCavalry I aim to misbehave.

    Me neither.
     
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  10. fallguy
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    fallguy Senior Member

    Makes a fella wonder if the stern was 7-10 tons too light before.:eek::oops::rolleyes:o_O;):mad::confused:
     
  11. Ad Hoc
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    Ad Hoc Naval Architect

    It 'appears' that they are adding a bulbous bow, shown in red, as there seems to be weld/scare marking at the intersection with the hull, and the fwd lines do not lend itself to such:

    upload_2021-6-22_8-2-3.png

    As such, it will move the LCB fwd..

    So, with presumably, the LCG remaining in a similar position pre and post, so the boat will now trim badly.
    The adding an extension aft, will mitigate this by moving the LCB back to roughly its original position, or at least roughly to the the location of the new/estimate LCG post build/refit....it 'should' all balance itself out.

    Whether this is a good idea/solution,....aaahh... that is a different question!
     
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  12. Ad Hoc
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    Ad Hoc Naval Architect

    This:
    upload_2021-6-22_8-7-46.png

    Wont do anything meaningful. I suspect this may be housing a sonar etc?
     
  13. fallguy
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    fallguy Senior Member

    a log floats..
     
  14. Ad Hoc
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    Ad Hoc Naval Architect

    That's what my wife says too... :eek::rolleyes:o_O
     

  15. comfisherman
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    comfisherman Senior Member


    Ugh.

    I wish it served as honorable a purpose as a sonar housing. That front cone has the telltale signs of being from a specific yard cranking out bulbs for fisherman. It's the healing oil/crystal/ snake oil catch all that's been popular in the west coast fleets the last decade. That pizza slice cone... I've seen a couple....

    Usually it goes down like this; fisherman A: is a very successful fisherman who hires a naval architect to laser scan his hull and virtual tank test his hull. He then gets a bulb optimized for his hull, built and installed by a competent yard.

    Fisherman B: has a bit smaller boat and a smaller budget as well. He doesn't want to pay for all the "fluff" of an engineer, so he hires a welder to make one "just like fisherman A". Only it isn't like fisherman A's, its shorter and narrower because they don't want to mess with bow rollers and anchors hitting. It's a more simplified shape and its potential for meaningful improvement in efficiency or ride decreases with each compromise.

    Insert fisherman C. He wants to be one of the cool kids and have a bulb, but doesn't know why. So he talks a drinking buddy into welding on a propane tank he got on craigslist. He's convinced that 1200 pounds of buoyancy radically improved the ride of his 70 ton steel boat. So much so, he convinces hoards of people who are just like C. It keeps the pills they sell at the gas station in business, "as seen on TV ", and psychic hotlines......

    This picture is very much a Fisherman C bulb....


    As to boat stretches, very popular with a specific hull up here. So much so the builder made a mold, but it was only about a 10% extension (about 4'). Guys wanted more and started doing 6' and even 8' stretches. It radically increases the vessel hold capacity.... with the side effect of a lot of blown out wheel house windows. A friend of my fathers did a 6' stretch an a hull identical to mine and in identical weather in 2013 he blew out windows while mine were fine. Was a fairly easy fix, we just glassed the window sockets closed as all our boats have flybridge tophouses now and the windows are redundant. Longer without taller bows made for different characteristics, not all positive.
     
    Last edited: Jun 22, 2021 at 9:38 PM
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