# Long shaft vs Short shaft motors



## GSSF (May 25, 2013)

The engine shaft length should be the same as the transom height on the boat.  An IPB 14 has a 15 inch transom, so the short shaft motor (referred to as having a 15 inch shaft) is what you need.  You wanna have the least amount of motor in the water while still giving you power and control and not blow out in turns.  Most of us with an IPB 14 have a short shaft motor _and_ a jackplate. IN my case, the cavitation plate on my merc 25 is about 2.2 inches above the bottom of the transom. Runs great and nasty skinny.

Running a long shaft on anything other than a 20 inch transom is going to put too much motor in the water, creating excessive depth required to run the boat, and drag.  No bueno.

Put that jonrude on the IPB and let it rip, my brotha.


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## WhiteDog70810 (May 6, 2008)

Different shaft lengths are for different transom heights. However, it is fairly common to put a 20" jackplate on a 15" transom because used 20" shaft motors are generally cheaper than used 15" shaft motors. There is no performance difference if you have the motors at the correct height (cav plate in relation to the bottom of the boat) with the correct prop.

Just beware that many used long shaft motors are high torque engines from sailboats and are geared for displacement speeds.

Hope this helps.

Nate


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## Stormchaser (Feb 10, 2013)

OK, thanks to both of you, I actually feel like I have a little common sense now. That's EXACTLY what I was thinking, but if you peruse Craigslist, all you see (vast majority, anyway) is micro skiffs with 20" shaft motors, and if you're searching outboards, you just find 20" motors for sale. 

Thought I was missing something, but I was thinking that exact same thing...that I SHOULD be using a 15" shaft on an IPB 14. Hell, even the small motors like the 9.9 and 15hp I see are mostly 20" shafts. I even saw one that was a 25" shaft, but I automatically assumed it was specifically a kicker on a big boat. 

Just making sure I wasn't crazy.


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## Stormchaser (Feb 10, 2013)

I often read of people saying their micro-skiff "plows" or whatever term you wanna use. I'm not a micro-skiff expert, but common sense says the less boat in the water, the faster you'll go, and the more fuel efficient it'll be. All of that can be accomplished by motor height, trim angle, and in small boats like a micro-skiff, even weight distribution in the boat. 
Of course, with everything there's a trade off. In our bayboat, my brother and I put as much weight as possible in the REAR, but that was simply to increase speed, since we fished tournies from time to time and required long runs to our spots. Even in a larger craft like a 102" wide bayboat, simply having the non driver move to the back would actually increase the speed by a couple MPH on the GPS. Now with a micro-skiff, you have to consider how the boat is gonna float (for draft's sake), so you can move items such as fuel cell and battery under the front deck to even out the weight from a motor hanging off the stern. But if you want it to perform, I guess you need to play with things to find the perfect balance for your own circumstances. 

Me, I want as much "safe" speed as possible, and don't fish puddles. I typically fish in approx. 1'-1.5' of water, but I sometimes make long(ish) runs to get there. So I will tweak mine to allow a little more speed, while not worrying if it drafts in poodle piss. As long as I can keep it around 6"-8", I'm golden.


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## springerscott (Jan 31, 2013)

When I bought my used boat, the guy had the longshaft 15hp on the back of the short transom. He wasn't happy with the performance and wanted a bigger boat and motor. So when I bought it, I immediately fixed that issue. I like having the engine higher. The IRL can get real nasty, real fast.


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