Motor height

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Mhopper
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Motor height

Post by Mhopper » Tue Apr 18, 2017 7:04 pm

How far above the keel should the cav plate be? Is there any type of rule or guideline on this ?



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Re: Motor height

Post by fishgitr » Tue Apr 18, 2017 7:20 pm

Even but no more than 1/2" above

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Re: Motor height

Post by Mhopper » Tue Apr 18, 2017 7:57 pm

I'm at two inches. :?

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Re: Motor height

Post by fishgitr » Tue Apr 18, 2017 8:17 pm

Way to much. You will lose water pressure most likely and cavitate

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Re: Motor height

Post by jacquesmm » Tue Apr 18, 2017 8:44 pm

Correct, too high. See this:
http://bateau2.com/howto/shaftlength.php
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BarraMan
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Re: Motor height

Post by BarraMan » Fri Apr 21, 2017 7:53 am

Well ........... it depends!

What is written above is generally correct and the article Jacque quotes basically covers what I am about to add for completeness.

My cav plate is running about 4" above the keel when the Jack plate is at its lowest - but my motor is on a 6" setback and I am running a semi-surfacing prop.

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Re: Motor height

Post by jacquesmm » Fri Apr 21, 2017 10:18 am

Yes, that makes sense. That article is a starting point. From there, you take in account what can be done with a setback bracket or jack plate, shallow water lower units, special props etc.
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Mhopper
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Re: Motor height

Post by Mhopper » Fri Apr 21, 2017 9:33 pm

i bought a setback plate. I don't like how it looks so I'm sending it back. I'm chopping her down a little in the morning. I will let you know how it goes... Thanks for all the input! That's the great thing about Bateau. You aren't buying a product. You are buying into a community!

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Capt UB
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Re: Motor height

Post by Capt UB » Wed Oct 18, 2017 2:55 pm

So where are you at with the motor now? You said you will cut down the transom? Any photo's?

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Re: Motor height

Post by TomW1 » Wed Oct 18, 2017 6:09 pm

I have been away for almost 6 weeks first on vacation and then with my dad in the hospital. Please don't confuse cavitation with ventilation. The plate on the motor is a ventilation plate. Cavitation is caused by damage to the front of the stem the creates bubbles of air that damages the propeller. Ventilation is caused by air being drawn into the propeller when it does not have enough water to cover it. You want to be on the edge of ventilation when you make a sharp turn.

Each motor has multiple holes to allow it to be adjusted up. Normally the range is 2 or 2 1/2". Smaller motors may have less adjustment than larger motors.

Propellers also must be adjusted for aluminum vs. SS. If you use a Jack Plate you can raise the prop higher. Geometry of the prop is significant. Rake, pitch, and where the cupping is placed all important. Rake can be progressive or straight. You get the Idea. Lots of things go into selecting the propeller.

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