shaft length

[chuck172]

I understand that if the transom to bottom of boat is 15" you need a short shaft. 20" a long shaft. I have a 1978 starcraft seafarer. The top of transom to the bottom of boat =17".
Do I use a short or long shaft outboard?

 

[tashasdaddy]

Re: shaft length

you need a long shaft, and may have raise the motor. what is the measurement straight down from the top of the transom?

 

[chuck172]

Re: shaft length

Straight down is 17"

 

[tashasdaddy]

Re: shaft length

long shaft, and play with height.

 

[jeeperman]

Re: shaft length

If 20" is long shaft, what is a 25" shaft?

 

[dajohnson53]

Re: shaft length

If 20" is long shaft, what is a 25" shaft?

Extra long. (I'm serious - at least with the older Johnson/Evinrudes I'm familiar with, 25" is designated extra long).

 

[dingbat]

Re: shaft length

Extra long. (I'm serious - at least with the older Johnson/Evinrudes I'm familiar with, 25" is designated extra long).

Then I guess the 30" is the extra, extra long shaft.

It really depends on the model and HP of the motor. In the high HP world, 20" is short, 25" is long and 30" is extra long.

 

[steelespike]

Re: shaft length

Straight down is 17"

Just to clarify.
If the transom is raked(angled) then the demension is longer measured along the transom than if you measure down at a right angle to the keel.

 

[chuck172]

Re: shaft length

If I measure down at a straight angle, it is 17". I'm not counting the keel. The boat has a somewhat deep V. Should I take the keel into consideration at all?
Seems like used short shaft motors are more common. I'm having a hard time finding the long shaft @ 9.9 HP.

 

[rickdb1boat]

Re: shaft length

Short shaft= 15"
Long Shaft=20"
Ex-long shaft=25"

You need a long shaft (20") lower unit and yes, consider the keel in the equation...