Outboard Shaft Length

[lambster]

"I have been "coached/dire

"I have been "coached/directed" to determine the correct shaft length of my outboard by measuring the length from the top of the transom to the bottom or keel of the boat. My boat has basically a sea drive that makes this difficult. I have seen engines listed for sale that are supposed to be 25" and they have the lower unit bolted directly to the exhaust housing. Mine has a 5" high spacer housing between the exhuast housing and the lower unit. I don't think I have a 30", but I am confused as to how to determine what I have based on engine measurement rather than boat."

 

[fastjeff]

The cavitation plate needs to

The cavitation plate needs to be about an inch below the bottom of the boat. Just worry about that--its' all you need.

jeff

 

[galamb]

"John, the 5 inch spacer is si

"John, the 5 inch spacer is simply a spacer and could just as easily be seen on any outboard. If you have a short shaft outboard, a 5" spacer (with a water tube and driveshaft extension) will turn it into a "long shaft" model.

Are you looking to measure to see what you would need to replace the SeaDrive with an outboard or are you looking for a measurement on your unit itself.

Measuring your transom will tell you what "shaft" length you need - 15-17" is short, 20-22" is long, 25-27" is extra long and above that is the more recent 30" shafts (which I don't know the name - extra extra long or super long???)

When measuring a motor to determine what it is, the diagram below is the accepted standard.

"