Mercury Chopper vs. Lightning ET

[Djohns]

Has any one done a side by side comparison of an ET vs. chopper in matching pitch? I have a 22p chopper and would like to buy a 22p ET. Would this be worth the money?$900. I am looking for a little more stern lift on my 05' hydrostream. The Chopper really hooks up, slip numbers <4%. My boat does extremely well up to 72-75mph. Once I get it on the pad I get some chine walking and have to come out of the throttle around 7250rpm. I believe the ET would provide a little less bow lift an more stern lift at high speed and might prevent the chining. Yes? No? Any thoughts? Any recommendations? Please indicate differences? (more rpm, less lift etc.):cool:
Additional info. Mercury 280 w/sportsmaster case.

Thanks!!!

[EFI25]

Why don' t you have JC or some other prop shop make an et cut on your chopper. The original et was nothing but a chopper reworked. I have a 28p lighting cut chopper that JC did for me that works great and it cost a lot less than buying a new ET.
Just a thought.

[78Vector]

Just out of curiosity, what Hydrostream only goes 75 mph with a 280 on the back ???
My Vector with a little 115 Merc 4cyl at the redline 5200 rpm (yes you read that right) will do GPS verified 62mph with a lousy Laser II 26 and 69mph with my Mazco reworked/thinned/ETcut 28 chopper.

This motor on my Vector would push it to well over 100mph.

Why so low on pitch ?
You may want to try more pitch and spin less rpm; you may well get more speed with a 24 or 26.
The ET definitely reduced my bow lift (maybe too much), but I don't think it raised the stern much.

[pyro]

Chine-walking should never be the limit to your top end. You have to learn to control it, to drive through it. It comes naturally after a while.

Your slip numbers can't possibly be under 4% unless your prop has extra cupping, in which case you should use "23" or "24" in the slip calculation. Choppers usually run 12 to 15 % on the XT hulls (assuming you have a Vegas or Voyager.)

Make sure you're not giving it too much trim, it doesn't need the nose flying sky-high to get good top end numbers. What height are you running at? (propshaft centerline in relation to the pad, i.e. "1/2 inch under the pad") Something is seriously wrong here...

[David Johns]

Hey Pyro,
I have a brand new 2005 Voyager XT with Nordskog GPS and Tach. "Sweeeeeet Boat" The motor is a fresh 2000/280hp with 10 hours on rebuild. This boat will run 75-78 with 1-4 people all day long. I just can't seem to get past the 78mph/7250 rpm mark before the chine walk begins. My setup is 0.5 inch below the pad measured at the centerline. I may need some seat time and some smoother water to practice on. How do you control the walk? Do you leave the engine level and let it slowly make speed or do you tap on the trim? Once I learn how to jump on the pad, do you think I should be able to turn a bigger wheel? 24-26p Does your hull do this? Any advice would be appreciated.

Thanks a bunch :o

[150aintenuff]

first of all you are way under propped and should be around 26-28P for that engine/ hull combo.......... find someone who has a chopper or et cut in your area and try it... it could be that the engine is working against your hull due to the fact that it is under propped and throwing the torque of the engine our of sync with the boats dynamic CoG at that speed.. smooth and steady adjustments generally are better than over comoensating to chine walk.. just like learning how to drive a car... slow smooth manuvers are better to everything than hard chops which can cause a dynamic push to one side and actually induce the exact thing you are trying to avoid.. also rough water and cross waves can induce a chine walk if not yet fully ballenced on the pad.

[pyro]

Your setup sounds right, the seat time and experience is the only thing missing. Vee hulls have a learning curve that will challenge you until you learn how to properly handle them.

People who ride in my boat, including my wife, often ask me why I keep tugging the wheel slightly while we're running. I try to explain, but they don't understand. We're always flying straight ahead, smooth and stable. On Sunday, my wife asked if she could drive it. I said OK. She got it up on plane, I reached over and nudged the trim stem "up" just a little bit, and told her to accelerate gradually. Around 60 mph, she experienced chine-walk for the first time, and she immediately let off the throttle, and said, "whoa, that's freaky." I'll let her drive it some more next weekend, and teach her how to control it with precise steering input. It took me most of my first season to get the hang of it. Now, I control it without even thinking. It like riding a bike for the first time. You have to give a slight nudge of steering input when it's needed to keep it going straight. You have to learn the "feel" of the boat, know what's it's going to do, and corect it BEFORE it has the chance to start chinewalking. You can feel when it's about to fall of to the side, and make a slight left tug on the wheel to keep it level on the pad. Just like riding a bike, I control it like second nature. I could almost close my eyes if I wanted to, and I would still be able to predict what the hull is going to do, and make necessary corrections to keep it levelled.

The Voyager is fairly heavy, so it's not going to start walking until 70-75 mph, when the sponsons rise above the water, leaving you to balance it only on the center pad. You WILL get the hang of this, it's not very hard. You should be running over 90 MPH without passengers once you master the handling. They tested a Voyager in '03 with a 225, and it was running close to 85. Get a 26 or 28 pitch Mazco RE or a Merc ET (or ET "cut", these can be created by modifying a big-ear chopper, should cost well under $400.) A stock big-ear chopper will have more bow lift. A big-ear with some extra cupping will lift like a mother, for carrying passengers.

-Chad

-Chad