Sea Sled madness. It’s in my brain.

Discussion in 'Fiberglass and Composite Boat Building' started by DogCavalry, Nov 11, 2019.

  1. bajansailor
    Joined: Oct 2007
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    Location: Barbados

    bajansailor Marine Surveyor

    You really do live in a wonderful part of the world - and all these houses have such lovely million dollar views!
     
  2. DogCavalry
    Joined: Sep 2019
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    Location: Vancouver bc

    DogCavalry Senior Member

    It's a really informative perspective. Even if everything else was just completely average, that incredibly useful front deck and cockpit would be enough to persuade me.
     
  3. BlueBell
    Joined: May 2017
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    Location: Victoria BC Canada

    BlueBell . . . _ _ _ . . . _ _ _

    And thank gawd 'cause the aft deck's useless.
     
  4. DogCavalry
    Joined: Sep 2019
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    DogCavalry Senior Member

    Yes. I made it too short. Less cabin, more back deck was the was to go it seems.
     
    fallguy likes this.
  5. BlueBell
    Joined: May 2017
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    Location: Victoria BC Canada

    BlueBell . . . _ _ _ . . . _ _ _

    Nothing a chain saw couldn't fix!
     
  6. DogCavalry
    Joined: Sep 2019
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    DogCavalry Senior Member

    Hmm. While I am pretty good with a chainsaw, the idea alarms me a bit. Still, major structural chains are common in boats, right?
     
    Stofferaus likes this.
  7. fallguy
    Joined: Dec 2016
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    fallguy Boat Builder

    As a fisherman, the aft deck is always a big deal. For you, less cabin means lcg moves forward as well; so less aft cabin means less for'd cabin?
     
  8. DogCavalry
    Joined: Sep 2019
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    DogCavalry Senior Member

    LCG doesn't really matter in Serenity, provided the prop or props can bite. Even otherwise empty, with five adults sitting on the foredeck, she planed easily. So I wouldn't change anything forward. Well, get some SS piano hinges and install the locker hatches.
    IMG_20230813_155853573_HDR.jpg
     
  9. DogCavalry
    Joined: Sep 2019
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    DogCavalry Senior Member

    Finally got paid on the Federal Government contract. Well, 50% anyway. I immediately contacted a prop shop and ordered a 16*17 SS prop, and asked them to put more cup in it, per @baeckmo 's recommendation months back, when I couldn't afford it.
     
  10. DogCavalry
    Joined: Sep 2019
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    DogCavalry Senior Member

    The prop shop is the famous VicProp, where the well known prop calculator comes from.
     
  11. BlueBell
    Joined: May 2017
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    BlueBell . . . _ _ _ . . . _ _ _

    That's a pretty limited calculator for your application, no?
    How did you compensate for aerated inflow water to the prop?
    I would have thought a chubby, cupped, 5-bladed, 21" pitch would have served your purposes.
    But that is providing you raise the engine up 2" - 3" as previously established.
     
  12. DogCavalry
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    DogCavalry Senior Member

    21" pitch would be too much. I don't think Serenity could go that fast
     
  13. BlueBell
    Joined: May 2017
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    BlueBell . . . _ _ _ . . . _ _ _

    Is that a gut feeling?

    I thought sea sleds were low drag at speed.
    Didn't you once calculate 50 - 60 knots at 230HP?
    You are limited by the 16" diameter, correct?
     
    Last edited: Nov 2, 2023
  14. DogCavalry
    Joined: Sep 2019
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    DogCavalry Senior Member

    Yes, 16" will be very tight.

    My calculations have been redone based on better formulas provided by @baeckmo , and observations IRL. My best speed will be around 40 knots, once everything is done to fair the hull and reduce drag.

    Once the prop is cupped, its effective pitch will be higher than 17.
     

  15. BlueBell
    Joined: May 2017
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    Location: Victoria BC Canada

    BlueBell . . . _ _ _ . . . _ _ _

    Just found out Arneson style drives are acoustically quiet.
    Much more likely to have orca encounters while making way.
     
    DogCavalry likes this.
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