Why does my cataraman porpoise after 27 mph???

FishinjeffFishinjeff Posts: 56 Greenhorn
I have one theory.  I do have the motors mounted one or two holes down.  I thought it would get a better bite offshore and it does, but in calm water it propoises really bad at higher speeds.  Can this be my problem???   

Replies

  • FS DanFS Dan Posts: 2,353 Moderator
    on the trailer, run a straight edge on the hull so it sticks out to the lower unit. the cavitation plate should line up with the edge, allowing 1" rise for every 12" of setback. each hole is ~3/4". As for porpoising, would need more info on the hull.

    FSD 
    Formerly Catmandew
  • RangermanRangerman Titusville FLPosts: 75 Greenhorn
    Are you trimmed up too far?  I don't have experience with cats, but my bass boat porpoises if I trim the motor up to high.  I trim it down and its fine.
  • kmagnusskmagnuss Posts: 3,171 Captain
    edited January 31 #4
    Too much trim?  Hull warped?  Too much weight in rear?  Different props with more lift can help.  Get some trim tabs and be done with it.
    Tarpon... everything else is just bait.
    Captain Keith Magnussen - Crooked Rod Charters
  • watergatorwatergator Fort Pierce Posts: 151 Deckhand
    Is this a new boat or have you made any adjustments recently other than lowering the engines
  • FishinjeffFishinjeff Posts: 56 Greenhorn
    It has really always done this, but when in the ocean it dosent bother me in rough water.  Smooth it is ridiculous.  I have since read many other cats with the same problem.  Mostly I have found a common item is the Hondas.  I am going to try 4 blade props.  Trimming does nothing.  I also have wedges added on motors.  I have heard about hulls being warped in the back.  Hard to see or test on the trailer.  I don't see any way to add trim tabs on this cat.  Just not enough area.  I have Bobs tabs on the motors.  
  • watergatorwatergator Fort Pierce Posts: 151 Deckhand
    Lowering the motors would be my first move. It sounds like the props may be catching and slipping if they're mounted too high. A 4 blade prop with some cupping should help with that without lowering the mount since they get better bite in dirty water. 

    Have you tried having the wedges removed? Depending on the transom setup you may not be able to trim down far enough which can cause it to porpoise. Have you contacted the manufacturer to ask about it? They may be able to help or point you to someone who can.

    Really shooting from the hip here but it may be worth removing any "ad ons" such as your bobs tabs and then working forward from a blank slate. Try adjusting one thing at a time and if it doesn't help then undo it and try something else. Dont be afraid to go back to something that didnt work if you get a marginal improvement with something else as the combination may fix it. 
  • FishinjeffFishinjeff Posts: 56 Greenhorn
    Watergator:
    The motors are already well below the bottom.  Drag, if anything may be an issue.
    When new, the boat would just pop the bow offshore to the point it was dangerous.  I put the wedges on to give it more negative trim.  That fixed that issue.  The manufacture was Leader boats.  Out of business. 
    he Bob's tabs did not do much good or bad.  I want to try to have the motors moved up 2 holes and I have 2 4blade props I got, but are 2 different pitches.  Used.  Ones to high and the other too low, lol  The motors weigh 496 lbs x 2.  Lots of weight for that boat.   
  • FishinjeffFishinjeff Posts: 56 Greenhorn
    This is with the trim all the way down.
  • FishinjeffFishinjeff Posts: 56 Greenhorn
    Lowering the motors would be my first move. It sounds like the props may be catching and slipping if they're mounted too high. A 4 blade prop with some cupping should help with that without lowering the mount since they get better bite in dirty water. 

    Have you tried having the wedges removed? Depending on the transom setup you may not be able to trim down far enough which can cause it to porpoise. Have you contacted the manufacturer to ask about it? They may be able to help or point you to someone who can.

    Really shooting from the hip here but it may be worth removing any "ad ons" such as your bobs tabs and then working forward from a blank slate. Try adjusting one thing at a time and if it doesn't help then undo it and try something else. Dont be afraid to go back to something that didnt work if you get a marginal improvement with something else as the combination may fix it. 
    See above
  • kmagnusskmagnuss Posts: 3,171 Captain
    Is it possible to stuff a couple hundred pounds of weight in the front of the boat somewhere?  Or move some of the weight that's in the stern to the bow... specifically the batteries?
    Tarpon... everything else is just bait.
    Captain Keith Magnussen - Crooked Rod Charters
  • FishinjeffFishinjeff Posts: 56 Greenhorn
    kmagnuss said:
    Is it possible to stuff a couple hundred pounds of weight in the front of the boat somewhere?  Or move some of the weight that's in the stern to the bow... specifically the batteries?
    I did that.  I moved both batteries from th back to the center console.  No change.


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