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  1. #1
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    Building a fast Sidewinder

    In New Zealand we have a sidewinders that are very similar to the US versions and rumor has it that the design was copied here in the early seventies.
    They were built by FiGlass as Sidewinders and Plylite as Panthers
    These were 16ft and there was a 14ft version as well called a Cheeta.
    They all have the same hull bottom which is a round Vee with two large Strakes each 8 inches out from centerline.
    These two strakes stop approx 16 inch short of the transom.
    They were raced here offshore early in the seventies and were often powered by a pair of 150 Mercs.
    They were nick named submarines possibly due to their tenancy to go through waves, taking out the windscreen.

    They were not an outstanding race boat IMO because they weren't designed or built for speed.
    They had 3 stringers, the floor was only 30-32 inches wide and stringers were a maximum depth of 4 inches so they were not at all rigid.
    At 40mph they were fine but once pushed over 60mph they lifted clear of any straight edges and behaved like they were on ice.

    So I brought one and have decided to try and make it go fast.
    To do this requires a total redesign and rebuild of most of the Hull.
    The Transom is cut off as is the transom well.
    The floor is out and the hull is bare.
    Its sitting in a perfect 19 deg cradle hanging on its Chines but with each strake resting on or near a full straight length support.
    I say "near" because when the hull is gutted the hull sucks up into one large Hook.
    Its getting remedial work on the inside of the hull but then more glass
    Then instead of 3 stringers its getting 5 and instead of a max stringer depth of 4 inches the new keel stringer is 8 inches deep
    This is achieved by raising the floor so that it sits into the 3rd strake out from the keel on each side.
    Thats a new floor width of 4ft
    The stringers raise up at the stern to form 3 Transom Knees and the keel stringer knee also connects to the new transom well floor.
    The Transom is mostly 2.5inch thick Marine ply laminate and is 25inch rather than 20 inch.

    The bottom of the hull needs some thought and input from others.
    IMO it will need some straight lines that go back to the transom but without too much lift
    Out of the mold they are shocking for wishy washy edges and flex.
    Basically Ill give the hull enough internal strength and hull thickness to aggressively blueprint end modify the bottom.
    I dont think an aggressive plank/ Pad is the a answer.
    There is a famous small offshore race bout in NZ named Chindit and it is a deep Vee with a small Tunnel.
    I like this concept and am looking at ways to create a similar system.???

  2. #2
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    Being you are in NewZealand........I think your limited to boat type so have to work with what you have. I have a old Sw....in the back yard..... one of too many boats. They do have bad hooks and felxi bottoms. I would think putting a heavy push on the inside of the hull to stress/flaten out the hook..... then glass in some core and stringers to make it straight and firm. I kinda wonder how those boats would be with a 3 foot streach in the back? Good luck with your project. Dave S.

  3. #3
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    Thanks Dave
    Its not so much that we are limited in boat type although yes there isnt the go fast selection that you have.
    We have Mirage 5000s, Bullets and Magnums etc.
    For me its about the Sidewinder/Panther being an Iconic NZ boat , even although its now clear that they arent NZ boats even if they were built here.
    I just like the style and always have.
    Its also a challenge of making one walk the walk.
    NZ ia a long narrow country on the edge of the Southern Ocean so our boating tends to be in choppy lakes and changeable seas.
    Fast boats here need to be strong so that adds another dimension the challenge
    The Molds are still around and I was told that there was a plan to produce a limited run again.
    Here is a Link to a Classic Kiwi race boat
    https://www.youtube.com/watch?v=UfCBBNbZn3A&t=2s

  4. #4
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    Edgewater,B.C. CANADA
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    The round pad bottom boats are tough to get to handle well above 60mph, was a Sidewinder up here years ago with a 260 Mercruiser that ran well into the 60's and handled great. Most the outboards got pretty tricky after 60.

    Dave
    1980 Cougar 19 tunnel,90 2.4L Bridgeport EFI in middle of restoration.
    1988 BAJA Sunsport 186, 96 225 Pro Max
    79 12' Auminum, 95 Merc 9.9
    RIP Stu
    "So many idiots, so few bullets"

  5. #5
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    The one in my back.... woods had a 327 IO.....was sposed to be fast.... never seen it run. When I got it had been converted to OB.....I keep it cause it's a flat deck.......And I am a boat junkee.......

  6. #6
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    I think it needs a flat pad to run fast. The Sidewinders built in my area also lacked rigidity

  7. #7
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    Pekin, IL
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    Not a good boat to try and run fast. We tried to get one to run with a 200 Merc. Never been so scared at 70.

    Rock
    Team Junk

    No sparkling wiggles in here, only dump truck grinches.

    "Screamin Heathen"

  8. #8
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    Hee Hee Just think of getting scared so easy........ya don't need a 300r and a high $$$ boat........

  9. #9
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    I have a plan and will post some pics when I can
    This Video link is what my Sidewinder bottom will probably end up looking like.
    Call me a gambler
    https://www.youtube.com/watch?v=tahrKRYBgQs
    Last edited by NZ Sidewinder; 11-22-2020 at 03:25 AM.

  10. #10
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    Nothing ventured nothing gained. Just add 3 feet. JMO......Bigger water ..... longer boat.

  11. #11
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    Lol
    Have considered it but the lines if the boat dont suit it.
    It would leave the drivers seat too far forward etc.
    In the 70s race guys put flat decks on them and moved the seats aft so that when they nose dived through large waves at speed the decks didn't get wiped of.
    Hence the nick name submarine.
    My next boat will be a Copy of that Chindit.
    Its built in Glass over Ply in a conventional frame and stringer method. (over 40yrs old now and still racing)
    The bloke built it under his house over a 12 month period and it has a race weight of 880lb (400kg)approx.

  12. #12
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    i drove a 14' sidewinder with a 112 Johnson on it. the kid that owned it said it was scary. well, with single cable steering, no trim on the wheel and the motor buried on the transom, he was right! thing was terrifying, and my 15' Whaler with a 90 v4 outran it ha. neat little boat though.

  13. #13
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    Ive almost finished glassing in the stringers
    What a job, it's huge.
    Ive put 5 in at 8 inch apart.
    This boat will be almost as rigid as a cored boat and I aim to make it the fastest Panther/Sidewinder that this country has ever seen.

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