Sea Ray issues

Discussion in 'Powerboats' started by cthall8143, Sep 24, 2007.

  1. cthall8143
    Joined: Sep 2007
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    Location: minneapolis

    cthall8143 New Member

    Hello all. I am new to this board, and I have a few questions...

    I just bought a 2003 sea ray 185 bowrider with the 4.3 liter motor. The first question is how, or what can I use to help the boat plane out better. When I hit the throttle the bow comes way up in the air, and takes a while to plane out. My last boat was a 1995 stingray with a 3 liter moter and that planed out much better.

    My last question is what is making the boat from going straight when traveling at slow speeds? It likes to go left... then right...then left again.

    Any Ideas?

    Thanks
     
  2. nukejr
    Joined: Oct 2006
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    Location: Stuart, Florida

    nukejr frmr Nuke Submariner

    You could install a variety of different models of hydrofoils (i.e., Doel-fins) to the lower unit of the sterndrive. This is a quick and easy addition and might be all that you need to help the boat.

    Second option might be to try a prop with a less pitch, or try a four bladed prop. This will give the boat better "hole shot" and will help the boat to get on plane faster. But there are consequences, though. You will end up losing top end speed, but it might not be that noticeable depending on how fast you typically run the boat.

    Lastly, trim tabs would also help. This is the most expensive option, and the most involved task (labor and technical difficulty).
     
  3. KCook
    Joined: Jan 2003
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    KCook Senior Member

  4. cthall8143
    Joined: Sep 2007
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    Location: minneapolis

    cthall8143 New Member

    Thanks everyone. I figured it may be something i need to get used to. Next season I may try out a few new props to see if that makes a difference or not.

    Thanks again!
     
  5. marshmat
    Joined: Apr 2005
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    Location: Ontario

    marshmat Senior Member

    Hi cthall,
    Nukejr's suggestions sound about right.
    The root of your boat's problem, in my opinion, is that its weight distribution and hull geometry don't go so well together. Sea Ray built the thing to be fast, compared to its length. That necessitates the centre of gravity being fairly far aft. But people won't buy a fast boat that's uncomfortable, so they give it a pretty sharp V-shape in the hull bottom to cut the waves. Now it's fast and comfortable, but too tail-heavy and with not enough lift to get up on plane easily. Unfortunately there is next to nothing you can do about these issues, inherent to the design of the boat, except for having the crew sit well forward in the boat.
    What you can do is to give it more lift in the stern. The drive-mounted hydrofoil will do this; so can the trim tabs. The wider, shallower prop with more blade area will give more thrust at lower speed, so you get through this phase quicker.
    The low-speed wander is not an uncommon issue in short, wide, high-speed planing hulls. The underwater shape off plane is not conducive to good directional stability. Trimming the drive up- not to the fully-up trailering position (which could damage it if the engine's running), but rather to the shallow-water trim angle, sometimes helps hold a straight line in some boats like this. You'll have to learn, though, that the boat will take several seconds to react to a change of helm, so don't overcompensate on the steering.
     
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  6. KnottyBuoyz
    Joined: Jul 2006
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    Location: Iroquois, Ontario

    KnottyBuoyz Provocateur & Raconteur

    See if you can find the Wide Open Throttle (WOT) specs for your engine. You should be able to obtain this RPM with the correct prop. Each inch of prop pitch should account for about 200 RPM. So for example; WOT spec is 5000 RPM and your current prop will top out at 4400 RPM. You'd need to remove (go down in pitch) 3" to achieve WOT. That's a baseline only. As suggested hull shape and trim tabs will help move the CoG fwd.

    For WOT test you should be half load, half fuel, half water etc. So if your capacity plate says 6 pers you should have 3 passengers or the equiv. weight on the boat when you test.

    There are other prop features, cupping, 4 blade, etc. that'll help but you'd have to consult a prop specialist. Try trimming your drive down as far as it'll go and bring the RPM's up slower to see if you can get it to climb out of the hole without pointing up to the sky!

    A good prop shop will may have a set of test props for your boat that you can try before buying.
     
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  7. techyjeff
    Joined: Dec 2007
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    Location: Alton, NH

    techyjeff Jeff K

    Not sure if you're still following this thread but just in case...

    I have a lot of experience with Sea Rays, have had a 270 Sundancer, and currently have both a 320 Sundancer and a 170 bowrider with a 3.0 ltr.

    My 3.0, most closely related to your 18', plans out fast as long as my drive is fully down, so that is my suggestion, to make sure your trim is all the way down before you hit it.

    Best of luck.

    Jeff
     
  8. yipster
    Joined: Oct 2002
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    Location: netherlands

    yipster designer

    my thoughts also techyjeff and at the stern sits a drive range adjuster you may trim in
     
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  9. techyjeff
    Joined: Dec 2007
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    Location: Alton, NH

    techyjeff Jeff K

    I did not know about the trim range adjuster; will have to check it out for future reference.

    Thanks for mentioning.

    Jeff
     
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