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Thread: why the 9.9 kicker?

  1. #1

    Default why the 9.9 kicker?

    hey guys, what is it about the 9.9 hp kicker you see on alot of bigger boats as the trolloing motor?..why not the 15 hp, which weighs the same and gives that extra "kick"?... is it the gas mileage that makes the 9.9 king?.....thanks larry

  2. #2
    Member Alaskanmutt's Avatar
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    Default Well

    Lower price and they are usually 20 - 30 pounds lighter i.e. 84 for the 9.9 Mercury 4 stroke and 115 for the 15 4 stroke and 300 or so difference in price plus like me I use mine on my inflatable skiff and it is top rated for 10 hp so Ikill 2 birds with one stone

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    Member patrickL's Avatar
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    Most importantly, you don't get anything extra out of having a 15hp for a kicker as long as your 9.9 is getting your boat up to hull speed. In most applications you see them on a 9.9hp is plenty for getting these bigger boats up to hull speed. Its not like a 15hp motor is going to get you on plane so why spend the extra money, carry the extra weight, or waste the extra gas?

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    Member jrogers's Avatar
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    Larry,

    Most of the 9.9's you see are the High Thrust version of the motors. They are designed for slow speed and have a bigger prop that is geared down for this application. Most of the 15-30hp outboards are meant to push smaller boats at higher speeds. Supposedly you can reduce the pitch of the prop on one of these, but it is still spinning faster than you need so it is less efficient at pushing around a large boat. That is the sales pitch anyways! I have a 9.9 on my 31' 12,000lb boat at it will push it at 5kts in flat, calm water.
    Last edited by jrogers; 12-22-2009 at 18:58. Reason: my typos made me sound like a hick
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    Member Maast's Avatar
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    In calm conditions you only need about 5 HP to bring a 28 foot boat up to its hull speed (which is roughly the square root of the hull length at the waterline).

    Any faster than the displacement hull speed and you're trying to push the boat up on top of the wall of water the boat is pushing in front of it (also known as planing or "up on step").

    Add another few HP to overcome headwinds and thats the maximum size of your kicker motor. Anything bigger than that is just wasting money and gas.

    Jrogers made a good point that the high thrust/bigfoot motors are geared down to spin their props slower but with more torque & bigger and higher pitched props so they're much more efficient at the speeds its actually going through the water. Its got to do with "prop slippage"

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    Member patrickL's Avatar
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    Ditto on what JRogers said. I forgot about the high thrust motors. I have hte honda power thrust on my boat but keep forgetting that its geared lower. So a question though. What about the new higher HP high thrust motors Yamaha is making. I think they go up to 50hp. In what application would this be useful?

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    Member jrogers's Avatar
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    More HP would be nice to have on the high thrust motors. While you would not push the boat any faster, when the wind is catching the boat like a sail or you are trying to climb a big wave with a 9.9 you could use more HP.

    One of the things on my 'to do' list is to get in some bad conditions, such as bigger waves and wind and switch to the kicker to see how much control I have. I have any run this in lighter conditions, and not really bad conditions and I think it would be valuable to see how it performs if I ever needed it in an emergency situation.
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    Member patrickL's Avatar
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    Good point. I don't nearly have the size of boat you have. The 9.9hp Honda Power Thrust I have seems to move the boat around very well. That being said, I've always tried to avoid bad weather so don't now how that would affect it. Your right though, sure would be beneficial to know.

  9. #9

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    Its a good idea to try out your kicker in less than perfect conditions to know what its capable of doing for you, then set your expectations/plan accordingly.
    I had occasion to use my 9.9hp on my 21' glass boat heading into 20mph winds and managed only to "hold ground."
    Unless its calm with little wind, your kicker will only afford you the ability to motor down wind with the ability to steer in order to find shelter.
    Its probably unrealistic to think it'll get you home...only slowly.
    Sorry if this is too obvious.

  10. #10
    Member ocnfish's Avatar
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    Default 9.9 honda extra long shaft with high thrust prop

    This set up has brought me back from Montague to Seward twice and a bit, in the last 5 years. From an eariler post:

    "Yesterday, I drove all the way to Cape Clear, Montague from Seward. After catching a 60" halibut I decided to head back but the engine would not start. Fortunately my honda 9.9 kicker started me back to port at about 5.5 mph. I also used the 6 amp charger to recharge the two starting and one house battery. After 3 hours of cooling and getting the volt indicator over 12, I managed to restart the 5.7 GM and the rest was a great ride."

    The Osprey 26 LC is about 9,000 lbs fully loaded and with the tide we saw about 7 mph against the tide we saw about 4.5 to 5 mph. In my 24 hours of operating in this mode, ugggggh, wind and wave did not make that much difference and I am sure the last one with 20+ quatering head wind and 5' seas with a chop on top. don't know why it worked out that way, it just did.

    The little honda is hooked up to the main fuel tank so ... if I could stand it with full tanks I might make it to Hawaii. That little motor saved my ***** twice now.

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