when to use Short Shaft vs 20"

[BoatGoFaster]

Here's the question, for drags, when is the short shaft preferred over a long shaft.

What advantage besides weight does shorter offer?

thanks.

[Edited by BoatGoFaster on 05-08-2001 at 01:02 PM]

[crowfly]

always

[O/B-1]

Weight closer to the water. Not so top heavy. Easier to handle.

[MirageMark]

The shorter the shaft, the lower the center of gravity. It's alot like a vehicle. It's easier to flip a tall/lifted truck than it is a lowered truck. Same thing in boats. The lower center of gravity gives more stability in overall handling and steering, which I'm sure would increase overall speed as well.

Mark

[TTriton]

Like the Grand Prix "Wider is Better" When Drag racing "Shorter is Better"

[Edited by TTriton on 05-09-2001 at 10:58 AM]

[RocketMan]

Sorry Mr. McCune, with respect to factoy production motors, you have your definitions wrong.

A 20" motor is a Long Shaft.
A 25" is an Extra-Long Shaft.
A 15" is a Short Shaft.

You don't have to look very far to verify this. Any outboard motor sales brochure will have this info.

[BoatGoFaster]

Short Shaft it is. Thanks for all the replies

[jimmyb]

couple of quick things to keep in mind on an SS...

1) weight is actually a bit heavier (~20#) than a 20" standard. the sand cast driveshaft housing and the heavy duty clamp bracket is heavy.
2) your engine is gonna be 5" lower. This could be an issue when you come off of plane. You really dont want to dunk your cowl too badly! Some boats really arent designed to have an SS motor.
4) you will have to mount a trim pump in your boat. Not an issue usually... just make sure you have room in your bilge.
3) cost and resale. a 20" motor can be sold to a much wider scope of boaters, so they are usually easier to sell. a 15" will cost you more off the bat, and you might have a problem selling it in your area. (although you probably wont have much problems selling it through the internet)

[TTriton]

Your right about the lengths. Since I don't use HOPO engine's I've always been used to 20" being concidered short shaft. All it took was me taking a look at my Midas Software on my other computer and that answered the quesiton. And Like i've said before.. I'm not always right.

[BoatGoFaster]

OK, so what would i use with either an Allison or Mirage??
for drag use.

[RocketMan]

15" Short Shaft

[jimmyb]

which allison? :)

2002, 2001, or 2000, I would go with 15"

XTB or 2003 (depending on application) 20"