Short or long shaft

Fish On Fabrications
TinBoats.net

Help Support TinBoats.net:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
P

putback

Well-known member
Joined
Aug 12, 2014
Messages
57
Reaction score
1
Location
Enosburg Falls Vermont
I really want to mount a Merc Mark 55 or 58 on a restore with a 16 inch transom. Every time I get a line on one its a short shaft, and always 100+ miles away so I've never measured one. Can anyone tell me if a "short shaft" will work on a 16 inch transom? I'm told shaft length is measured from Clamps where they contact top of transom to centerline of prop shaft, that right?
 
A short shaft is 15"
A Long shaft is 20"
An Extra Long shaft is 25"

outboard%20shaft%20length.gif
 
A boat manufacturers idea of transom height and a motor builders idea of long shaft, short shaft will never be the same measurement.
 
Right off the bat, you cannot take a tape measure and lay it against the transom and measure it. That is not how a transom is measured. Your measurement will always be long.
Outboard transoms are designed at around a 15 degree angle.
With this in mind the way to measure an outboard transom is to either take a straight edge off the bottom of the boat and measure from the top of the transom to a point on the straight edge that will be perpendicular to the bottom of the boat.
Or, take a square and come off the bottom with it and measure to the top of the transom.
Now, the simple answer to your question is to use a short shaft engine.
 
Thanks, clear and concise. Using the square I have 15.5 inches of transom height. Of course that means I've missed 2 possible Mark 55's and 1 Mark 58 due to my ignorance. Hard to come by these in Vermont.
 
Pappy said:
Right off the bat, you cannot take a tape measure and lay it against the transom and measure it. That is not how a transom is measured. Your measurement will always be long.
Outboard transoms are designed at around a 15 degree angle.
With this in mind the way to measure an outboard transom is to either take a straight edge off the bottom of the boat and measure from the top of the transom to a point on the straight edge that will be perpendicular to the bottom of the boat.
Or, take a square and come off the bottom with it and measure to the top of the transom.
Now, the simple answer to your question is to use a short shaft engine.
Click to expand...


That's good info!!!!
 
I have a buddy just outside of Nashville that has a complete Mark58 he would like to sell. Like me, he leans more toward Johnson and Evinrude but a boat that he recently purchased came with that engine on it. PM me if you are interested, thinking that he will not want a lot for it.
 

Similar threads

S
Mercury 20hp 4 stroke 20" long shaft convert to 15" short shaft
Replies
1
Views
712
Bailey Boat
B
H
Weekend auction lot of outboards
Replies
5
Views
691
hoarder
H
F
Large lot of 70's and 80's Johnson and Evinrude outboards
2
Replies
27
Views
2K
captain cletis
C
Douglasdzaster
Trolling motor acting up
2
Replies
28
Views
2K
Douglasdzaster
Douglasdzaster
B
Short shaft/long shaft
2
Replies
24
Views
2K
cyclops2
C

Latest posts

Top