Diablo Grande

Discussion in 'Powerboats' started by PeterK, Mar 14, 2013.

  1. PeterK
    Joined: Dec 2009
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    Location: Atlanta, Ga

    PeterK New Member

    Hello all,
    Anybody here has/had/built Bolger's Diablo Grande or Surfmaster?
    I am planning to build one, intrigued by the hull shape too...
    Any first hand experience of the boat's behavior?
     
  2. Northman
    Joined: Mar 2007
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    Location: Norway

    Northman Junior Member

  3. Yellowjacket
    Joined: May 2009
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    Yellowjacket Senior Member

    The original Diablo planing surface shape was an unashamed copy of a typical D class rollup racing runabout of the time. Even though it was made from thicker material and the upper surfaces were shaped in a utiltarian mode, the bottom was actually all race boat. As a result, it is actually a fast and capable boat that will handle more power than it looks like it should. There was on builder on the web that put a 40 or 50 hp motor on and it went very quickly.

    The Diablo Grande is just the same thing only bigger. The only downside is that there isn't much framing or stiffening of these stitch and glue versions, so they tend to be a bit wimbly if you put more power on them than is recommended and go out beating them up in rough water.
     
  4. PeterK
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    PeterK New Member

    Thanks Yellowjacket,
    I guess you meant that folks who built the DG took out the (awkward) raised deck and THEN it became too flexible?
    Could it be reinforced with a egg crate-like structure?
    Creating extra buoyancy, imparting stiffnes to the hull, creating more of a walk around deck?
     
  5. Yellowjacket
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    Yellowjacket Senior Member

    No, the basic Diablo is pretty flexible, when compared with racing boats. Racing runabouts have topside decking that, in addition to the framing structure, makes the boat a closed tube up front, and two closed tubes beside the cockpit. That results in a very stiff structure in torsion, even though the plywood is typically only 5 or 6mm thick, and the entire 13 ft hull only weighs 120 - 140 pounds.

    As a result the racing hull won't twist much at all (provided things inside aren't broken). The Diablo, while being made out of thicker plywood has only the seats and nose piece to keep it from twisting, there is no top decking. As a result, it isn't very stiff in torsion.

    They didn't recommend much power for the Diablo, but the hull is dynamically capable of handling more, so lots of folks put more power on it and the hull can go pretty fast with more power. It's just that if you are going fast the boat will feel flexible.

    The Diablo is a pretty robust design, from what others have said about beating on it and it and not having any problems, it's not really a weakness, it's just that it isn't the stiffest hull around, that's all.

    The Grande is a lot stiffer since it has the floor that boxes the structure and makes it a pretty stiff hull.
     
  6. Petros
    Joined: Oct 2007
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    Petros Senior Member

    do you really want to build a boat named "Big Devil"? Hmm, seems like temping fate...there is long history for avoiding anything that brings bad luck with boating.
     
  7. PeterK
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    PeterK New Member

    No doubt it is something to think about.
    Perhaps I'll re-christen to something more agreeable. It is the ease of build and the unusual hull shape that made me interested.
     
  8. acampoverde
    Joined: Apr 2013
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    Location: Ecuador

    acampoverde New Member

    Diablo reloaded

    Hi everyone. just wanted to share pictures of my Diablo. We used 9mm plywood instead of 6mm. Also the transom was reinforced. It is suuuper fast. 65hp etec. I know it is crazy, but the boat performs great and we got a really good deal on the Etec.
     

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  9. Easy Rider
    Joined: Oct 2009
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    Location: NW Washington State USA

    Easy Rider Senior Member

    I've got a 16' Crestliner alum w a 40hp e-tech w that extended tiller and can imagine you've got to hold on to that tiller tight at the speeds you must go w the 65 on the 15' Diablo.

    The first pic is of an 18' Grande I saw in Ketchikan Alaska that was being used as a dinghy. The boat alongside had towed it to AK from the Seattle area. It's hard to imagine the Diablo having a stiffness issue looking at the seats/ structures inside the hull. The owner said he had no problems towing from Washington.

    2nd pic is my Skiff. I think the reason the tiller is so long on the e-tech is to give the tillerman half a chance at controlling all that torque from the low gear ratio (2.67-1) and resulting big prop. When underway solo sitting on the stbd side with an otherwise balanced load I would need to weigh more (I weigh 185lbs) to balance the boat. W the 65 on the 15' Diablo I can imagine not having enough weight on the stbd side to keep the boat level w TWO people sitting on the stbd rail.

    acampoverde,
    Why didn't you build the Grande?
     

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  10. acampoverde
    Joined: Apr 2013
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    acampoverde New Member

    Easy Rider

    This is my first boat and I thought 15 ft was good enough. Also I am in Ecuador and there is no epoxy here. I had to import it from the U.S. so I didn't want to build something too big. Before the etec I had a suzuki 2 stroke 30hp. This boat is very stiff with all the structure. The etec is brand new, i have used the boat just one time with this engine. I still dont have the right prop, but with the 17 pitch it went 37mph. It goes on plane in one second so i guess the right propeller is probably 20 or 21 pitch. I am planning to build a side console, its a little scary to go so fast with the tiller.
     
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