How to measure boat for kicker motor length?

[drbrand]

I have a Tracker Targa 2000 20' boat and was looking at putting a new Mercury 9.9 prokicker on it. How do I determine if the kicker should be 20" or 25"? I had a 20" on it previously and it worked fine as far as I could tell, but I never knew if that was correct for this boat. The 20" kicker prop was always below the bottom of the boat seeing it was mounted to the side and the sides of the hull are shallow.

[bogey]

When I got my last kicker, they told me that the cavitation plate on the kicker should be at or just lower the bottom of the boat.

[drbrand]

I found this page that talks about sizing up shaft length. It states the same a Bogey stated. The cavitation plate should be at or just below the bottom of the transom. But if your kicker motor is mounted to the side of the main motor like everyone's is, wouldn't you want to be just at or below the transom where the kicker will be mounted which may be shallower than the center of the transom? You might have a 25" transom in the middle, but it's only 15" or 20" deep on the ends of the transom where the kicker motor will mount.

http://smalloutboards.com/shaft.htm

[T Mac]

On that particular boat don't get a 25" ...pretty sure t'll drag.

[Shep]

If you had a 20" before, and the prop was below the bottom, get another 20".

[oldntired]

My boat has a 25" transom and I installed a 20" kicker. Works fine. If your kicker shaft is to long it may not clear the water when it is tilted up.

[ebijack]

length also depends on how/where you use it. if you fish big water, a 20 even on a 20 transom the prop will come out of the water in bigger waves and you lose control when that happens. i went to a 25 on a 20 transom just for that problem. i can not trailer with it in the down positition but that's not really a problem for me. and when running it's plenty high up trimmed all the way up.

[T Mac]

Originally Posted by ebijack

length also depends on how/where you use it. if you fish big water, a 20 even on a 20 transom the prop will come out of the water in bigger waves and you lose control when that happens. i went to a 25 on a 20 transom just for that problem. i can not trailer with it in the down positition but that's not really a problem for me. and when running it's plenty high up trimmed all the way up.

Yeah...Ebi...but you don't have the same boat asthe one that is in question.
The model in question tends to dig really low in the back ....especially during the holeshot.
As you will recall, the glass 20' Targas hydro-locked a lot of main engines, let alone drug kickers.

[Grampa_Joe]

Yeah, you want a 20". The 25" part is on the centerline of the boat, over on the side where a kicker is mounted a 20" works perfect and, like Tmac said, it will drag in the water. The only time I ever put a 25" kicker on was a Boston Whaler, and the gunnel was almost taller than is outboard.
I don't know of a manufacturer that installs a 25" kicker from the factory either.

Joe Carlson

[Waxy]

Now I'm really confused.

I initially wanted a 20", then was told I need a 25", and now the concensus seems to be 20".

I want to put a ProKicker on my 1900 Pro V. Do I want a 20" or 25" model?

Waxy