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  1. Member
    Join Date
    Aug 2017
    Location
    Alabama
    Posts
    64
    #41
    How do I know if a prop has more cupping?

    I know nothing and I mean nothing about props.

    I'm not going to start welding beads on the bottom, at least for now. The boat ran like a scalded dog before I restored it. I have tried very minor trimming differences and can't make it not porpoise as well.

    I know the most common cause of porpoising is weight distribution but I've moved things around balancing them like they were prior to the restoration and it's still bouncing. It weighs more but they balance should be very, very close to what it was before I started.

    I'm going to raise the motor first, then I'll try a different prop, then I'll put on a jack plate if I have to.

  2. Member
    Join Date
    Feb 2011
    Location
    Ellettsville IN
    Posts
    4,122
    #42
    This boat has a pad and my guess is that with the extra weight your not getting up on the pad all the way. What are your break over RPMs? What kind of prop are you running what shape is it in? You need more stern lift i would bet

  3. Member
    Join Date
    Aug 2017
    Location
    Alabama
    Posts
    64
    #43
    Thanks for all the replies.

    I raised the motor one hole today and took it for a quick test drive. I had to get way up in a creek to find water smooth enough to be able to tell anything about it. Raising the motor helped a tremendous amount. I was able to run the throttle back up to 5000 rpm and trim it up enough to acheive 45-46 mph. Any more trim or throttle than that would cause her to start bouncing again. I have a SS prop on the way and if it makes as much difference as raising the motor one hole, the porpoising will be gone. If it doesn't get rid of it, I'll save my pennies and get a jack plate. I was able to trim the boat up enough today to get the spray back just a little behind me while running hard. That's a whole lot less boat in the water than what I had last weekend. I couldn't run up high enough to get the spray back behind the console.

    Gsmith, currently running a Solas 13x21 aluminum prop in fairly good shape. The leading edge needs cleaning up but it's not that bad. I'm sorry but I don't know what you mean by break over RPM's. If you'll explain what that is, I'll do my best to answer the question. LOL

  4. Member
    Join Date
    Aug 2017
    Location
    Ruston, Louisiana
    Posts
    136
    #44
    What prop & pitch did you decide on?
    1998 Xpress H51, 90hp Yamaha, 6" Vance JP, MotorGuide Xi3, Lowrance Electronics, Micro Power Pole...

  5. Banned
    Join Date
    Jun 2017
    Location
    Warner Robins, GA
    Posts
    506
    #45
    Quote Originally Posted by Bassnailer View Post
    My brother had similar issue with a Lowe Stinger. It would porpoise unless trimmed way down. He had trim tabs installed and this cured the problem. The dealer put them on, but they were just small aluminum plates in this shape > which were welded on the transom. Easy fix, rides better, and was not too spendy. By brother loves his tin rigs, I love my glass boats. We have the best of both worlds this way.
    This ^^ A buddy of mine was having the exact same issues. After trying pretty much everything (jackplate, weight distribution, etc), he had the trim tabs installed and the problem was fixed. Then he traded it for a new glass Ranger

  6. Member
    Join Date
    Apr 2015
    Location
    Aurora Missouri
    Posts
    2,764
    #46
    Extra cup in the prop is your friend.
    Bruce Phillips
    1995 190 DC champion ......1995 200 xri merc

  7. Member
    Join Date
    Aug 2017
    Location
    Alabama
    Posts
    64
    #47
    Quote Originally Posted by bulldog44 View Post
    What prop & pitch did you decide on?
    I don't remember. I'll let you know when it gets here. I didn't decide, the prop guy decided. I figured he knew a heck of a lot more about it than I did.

  8. Member
    Join Date
    Apr 2012
    Location
    Weaubleau MO
    Posts
    1,473
    #48
    I had a2072 Grizzly from BPS with a 125 could not run it without motor trimmed full in. Same problem you are having tried all the weight fixes and nothing worked, old timer said it had no HOOK on the transom, had a couple 1/4" welds on bottom on transom where it met the bottom of boat fixed the problem a lot cheaper fix instead of chasing all the other maybe this will work ideas. could run boat normally with no problem.

  9. Member
    Join Date
    Aug 2017
    Location
    Alabama
    Posts
    64
    #49
    Update on the thread. I ended up getting a Laser II 20P. Raising the motor one hole helped the poropoising and adding the stainless prop helped more. I can run up to around 5500 rpm now with no porpoise at all on slick water and up to 5000 rpm with chop before porpoising starts. It seems to me that I'm real close to where it needs to be. Top speed is still not what I would like for it to be. 53 on speedo prior to the boat restoration, and 44 on GPS now. The speedo runs higher than the GPS by about 3 mph so I'd say I've lost 6-7 mph by adding 200 pounds to the boat. Is that normal?

    I have a Vance 6" jack plate on order. Hopfully that will get her up out of the water a little more.

    Fuel economy straight up sucks. I'm not running her at WOT often and I'm seriously only getting about 1.5 mpg with the Yamaha 115 V4 2 stroke. The carbs were cleaned last fall. I'm wondering if I might have a hole in the fuel pump diaphragm.

  10. Sprint Boats Moderator Bassmeister's Avatar
    Join Date
    May 2004
    Location
    Calhoun, Ga.
    Posts
    46,440
    #50
    Quote Originally Posted by John Jackson View Post
    +1 here. You probably were not lifting the bow with the battery up front. Now you are lifting the bow but your setup won't hold the bow up. More cupping or a prop with a lot of bow lift, like a tempest, should help.
    Also the guy with the weld bead is hitting on something common with aluminum boats. The pads flex and don't work as well as fiberglass pads, and the weld bead can give a bite that can partially compensate for the flex.
    This^^ Your prop isn't carrying the bow, it drops, then it lifts it again, it drops....porpoising...

  11. Member
    Join Date
    Apr 2012
    Location
    Insomnia, near Seaford Delaware
    Posts
    35,513
    #51
    Quote Originally Posted by Bassmeister View Post
    This^^ Your prop isn't carrying the bow, it drops, then it lifts it again, it drops....porpoising...
    Which is an indication of not enough power. The fuel economy issues can come from too much drag, inefficient boat setup, too much hull in the water.

  12. Member
    Join Date
    Aug 2009
    Location
    Kings Mtn., Kentucky
    Posts
    8,820
    #52
    I had one that proposed badly without a whale tale. Took it off & put a turbo 1 on it & removed whale tale & it never proposed again. I would bet a new prop will take care of it completely.

  13. Member
    Join Date
    Aug 2017
    Location
    Ruston, Louisiana
    Posts
    136
    #53
    Quote Originally Posted by Les Young View Post
    I had one that proposed badly without a whale tale. Took it off & put a turbo 1 on it & removed whale tale & it never proposed again. I would bet a new prop will take care of it completely.
    what motor and pitch prop are you running?
    1998 Xpress H51, 90hp Yamaha, 6" Vance JP, MotorGuide Xi3, Lowrance Electronics, Micro Power Pole...

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