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greauxpete

Kicker motor bracket challenge 2320

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I am trying to decide where to mount a kicker motor bracket for a 9.9 yamaha 2 stroke. Currently, the tow eye and trim tabs are in the way. It looks like I will also need a spacer block to move the kicker bracket away from the transom.

 

Questions:

 

1. Does anyone see a strength issue with bolting the kicker bracket at this location on the transom?

2. I am hesitant to remove the tow eyes on the transom, but one side will need to

Be removed to mount the kicker bracket.

Anyone see any issues with this?

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Edited by greauxpete

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I'd be more concerned about the trim tab location. What's your plan with that? Do you have access to the inside of the transom eye to remove it? As long as your transom is good, I wouldn't be worried about the weight. The boat can be rigged with twin 150's so the strength is certainly there.

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Mark,

 

Good point. My thoughts are, when running normally at high speed the kicker motor will be out of the water. The motor extends away from the transom a few inches, but a 2"-4" spacer (starboard) will be needed to get the motor past the trim tabs in the stowed position. When the kicker motor is deployed the bracket extends out about 6 inches away from the transom and should be away from the trim tabs and traveling no more than 6 mph (hull speed).

 

I realize the lower transom is stout, I was more concerned about the upper transom, where I intend to mount the kicker bracket. What do you think?

 

I have 4" access hatches on the inside of the boat. I should be able to snake in a couple of backing plates.

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No worries about the strength of the upper transom. Think of it this way.... Those are lifting eyes/towing eyes.

By 4-6" spacer, do you mean 4-6" thick? That's where my concern would lie with this. That's a ton of leverage on the hardware even with the use of backing plates. How much would you have to move the trim tabs to make it work without the spacer?

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Mark,

 

Yes, I re-measured, the spacer will need to be 3". I think it might work. It looks like only four 3/8" - 316 stainless bolts will have a factor of safety of 10 combined tension and shear). I should have plenty of clearance between the motor in the up (stowed) and down (operating) postion. I looked behind the transom and everything looks clear as well.

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Edited by greauxpete

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3 is much better! What about the tabs? Could they be moved inward slightly? I guess another option may be a tab with a shorter chord and longer span?

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I think the tabs will be okay where they are. The spacer will move the kicker out 3-4" from the transom. The motor has a short shaft and in the stored position the lower unit is higher up on the transom. When engaged the motor moves out more than 12" and also drops. I'll test fit it next week when I get my spacers and post pics.

Debating about over drilling and filling with fiberglass. I may just drill and soak the inside diameter of the hole with west epoxy.

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Here are some rules of thumb for sizing kicker motors I stumbled upon:

 

Kickers will only push to hull speed or displacement speed,(will not get on step) which is:

 

1.25×SQRT (wetted length of vessel) mph

 

Power requirements are roughly:

 

1 hp per 1,000 lbs of weight under ideal (calm conditions)

 

Double this requirement for wind, current and wave.

 

Therefore, a 5,000 lb vessel will require at least 5 hp in calm conditions and 10 hp under moderate wind current and waves.

 

I have a 1991 yamaha 9.9. We will see if these parameters check out.

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It should work just fine. You may have to go with a low pitch prop just so it's not working TOO hard....2320 is a BEAST

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Here is a rough mockup of the kicker placement with the 3" spacer block:

 

Note: The end of the rod taped to the bracket board represents the elevation of the motor cavitation plate when the bracket is lowered all the way down. The motor moves away from the bracket by 12" when lowered. In the stowed "up" position, there is at least 3" of clearance between the lowest point on the motor and the trim tabs.

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Edited by greauxpete

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Finally installed the kicker.

Used a panther 55-0416 4 stroke

bracket with 16" of stroke. It is very easy to deploy and lift on the water.

I have a 15 HP Nissan - 4 stroke (with 5" shaft extension kit from Bay Manufacturing)and it pushes the boat at about 5 knots.

Also installed a new motor (2002 Mercury Optimax - 225 HP) after blowing my rebuilt carb'd 1995 Mercury 225 - that's another thread tho - trying to get the mechanic to honor his warranty..

 

Ordered several kicker brackets before settling on the Panther (including an second hand OMC bracket), glad I waited to drill holes. I trailer the motor on the bracket but I ratchet strap the motor up to the boat using the tow hook to get the weight off the bracket. Doesn't seem to be an issue. 5 mph isn't fast but it will get me home eventually.

 

Steve

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Edited by greauxpete

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I like it. Looks good and it should provide an emergency back up. I may end up asking you more questions later. I had considered a kicker for my R207, but sold it. Now I have a new Sailfish and may think about it again sometime.

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Fullthrottle, ask anytime, I'll do my best to help.

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I used L2x2x1/4" aluminum angle (running up and down) to stiffen the back side of the transom.

Those lower holes were nearly impossible to reach. My buddies 15 year old

son was the only one who could reach the nuts with a wrench and his skinny arms.

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I did some comparing of your transom to mine - I doubt there is room to safely add a kicker. I can somewhat access where a backing plate and nuts would go, but I don't have much height anywhere to add a kicker.

Edited by FullThrottle

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