Rascal mahogany runabout - video of high speed passes

Discussion in 'Boatbuilding' started by peter1708, Sep 15, 2015.

  1. peter1708
    Joined: Jun 2008
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    Location: washington

    peter1708 Junior Member

    For anyone interested in building this design, I was finally able get some reasonable footage of what the boat looks like at speed. In the short video, there are 4 passes, the first 3 are at 50-51mph, the last at 40mph.

    The motor is a 1961 Mercury 800, turning a 22" pitch chopper prop.

    Pete

    https://www.youtube.com/watch?v=AqLSSJWOTko


     
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  2. Woobs
    Joined: Jul 2015
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    Location: Newmarket, Ont

    Woobs Junior Member

    Very nice! The Rascal is a great design :)
    Here is another Rascal with similar performance (56mph) but, a modern 85HP Merc (old decals).
     

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  3. peter1708
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    peter1708 Junior Member

    Hi Woobs, that is a very striking boat! The engine decals are a great touch - vintage look with modern performance and reliability!

    Pete
     
  4. Woobs
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    Woobs Junior Member

    Yes, one of our club members built it and after many years of use, another club member helped out by doing a total refinish/makeover. They are a great design.
     
  5. LP
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    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    Nice looking boat.

    What up with the porpoising?

    Looks like a motor trim error or a weight distribution problem.
     
  6. peter1708
    Joined: Jun 2008
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    Location: washington

    peter1708 Junior Member

    Hi LP, thanks for watching.

    Great observation about porpoising. The lake was pretty rough this day, causing all the bouncing in the video. But, you're right, the motor trim determines if she will porpoise in certain conditions, depending on what you want to do. I have an after market power tilt/trim unit on just for this reason (CMC PT-130).

    For speeds up to 45mph or so, she rides very smoothly and very flat, with no bouncing at all, due to the ability of the power trim to maintain hull ride angle, forcing the bow down to a more level boat trim.

    To get to speeds above about 45mph, the motor is trimmed out much more, forcing the hull out of the water so that the boat can "break out" - ride only on the pad for the last foot or so of the bottom. That transition zone - going from level ride to having little to no hull in the water, or "break out", is where the boat will porpoise. Once on the pad, the ride is like floating on air, the video below kind of shows this. At about 48mph or so, you'll see the ride really get smooth - the boat has "broken out". (Note that I'm trimming the motor out beyond a flat ride right from the start, so there some porpoising through the mid-range speeds).






    It's definitely a learned skill to be able to drive the boat fast and be able to get through that transition zone from slow to fast as quickly as possible, still learning.

    Pete
     
    Last edited: Nov 3, 2015
  7. tom28571
    Joined: Dec 2001
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    Location: Oriental, NC

    tom28571 Senior Member

    Thought I recognized that one. I had the pleasure of driving it on Lake Muskoka in 2003. Chris Bullen built it, if I remember his name correctly. Still beautiful.
     
  8. Woobs
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    Location: Newmarket, Ont

    Woobs Junior Member

    Yes, you are correct. "Sam's Smile" is the name Chris gave it. It was the first wooden boat Chris had ever built and sparked his passion for the "woodies". The facelift was done over the 2014-2015 winter by Rich Hughes and his wife, Linda Hughes whom did the interior.
     

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  9. tom28571
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    tom28571 Senior Member

    Did Chris not do more on the restoration than lean on the deck?:)
    I think the origin of the name is kind of neat too.
     
  10. Woobs
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    Woobs Junior Member

    Yes, he pushed his pen through his check book!
     
  11. tom28571
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    tom28571 Senior Member

    That works.:D
     
  12. davidmhoj
    Joined: Feb 2016
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    Location: South Jersey

    davidmhoj New Member

    Hey Pete-
    I have watched all of your videos on youtube. Your boat and craftsmanship is what got my gears turning about this specific boat. I can tell how much you must be proud of yourself as you always seem to be grinning-that coupled with the fact of how much fun that thing seems to be.
    I noticed your most recent video from the other day with the new(er) motor. Would you mind sharing more details of it, mainly what you feel the output HP is?
    I don't know if I am going to take the plunge and attempt a build of this model, or something similar. Perhaps a culmination of a few designs, but this one is pretty much what I'm after- something just a hair bigger- possibly stretched.
    Thanks for the inspiration. My wife may have some other choice words in the near future, but at least I got the green light, so the hardest part is over so far!
     

  13. peter1708
    Joined: Jun 2008
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    peter1708 Junior Member

    Hi David,
    Thanks for watching and you'll have more fun (and frustration:) ) then you ever imagined building your own boat. That green light is vital first step, congrats on receiving the go ahead!

    The motor in the clips above is a 1961 Merc 80HP. The newer motor is a 1962 100HP (the 100HP power head fits into the cowling of the 80HP) and has some modifications, such as a modern ignition system (modern meaning late '70's solid state - no points) and other assorted tweaks. It was rebuilg completely and I'm 7 hours into a 10 hour break in schedule. I haven't had maxed it out yet, but with warmer weather coming, hope to do so. The 80HP went 53mph and I suspect the 100HP MAYBE will increase that by 4-5 mph. That being said, the real performance difference is in acceleration; going from 20 to 50 mph is much, much quicker now.

    Both of these motors are crank shaft HP rated. I think that around 1983 or so, Mercury (and all manufacturers for that matter) switched to prop rated HP. I don't know what the prop HP is for these early '60's engines are,but when Mercury went to prop rated HP, I've read that the 140HP was re-rated to 115HP and the 115HP was re-rated to 90HP. Don't know if that applies to the early '60's engines, but it's all the data that is available (as far as I know). I suspect the 100HP is probably 75-80HP at the prop. These engines are also a lot heavier than the '80's to '90's two strokes.

    You mentioned stretching this design and there was a builder did that and documented his build on the Wooden Boat forum; I believe he stretched it to 16'. I have also seen photos of someone who put a smaller second cockpit up front also.

    There are many cool designs out there and whatever you decide to build, you'll have something to enjoy for the rest of your life. Good luck, you won't regret it!

    Best,

    Pete
     
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