Short shaft motor on long transom

[Johnathon182]

Recently bought a Tohatsu 20hp 17 inch short shaft motor, the boat I have had a 20 inch transom. I’ve read lots of forums stating that installing an setback plate will make this set up work. Has anyone able to make this similar set up work? If so can I have some tips.

 

[JimS123]

Anything can be "made" to work. But is that the right way?

Trade the boat and/or motor and DIRTFT.

 

[KJM]

Why did you buy a motor you knew was too short?

 

[Texasmark]

If I am recalling comments from the big guns on here the rule of thumb is 6"/inch. So that would put you out about 30" and would be similar to mud boats propulsion.

 

[racerone]

I am not sure that they market motors for 17" transoms.-----Many folks are confused by the term short and long shaft.-----It refers to the height of the boat transom.----Thus 15" motor is designated a short shaft and 20" is a long shaft.-----It is not some dimension on the motor itself.-----And it is not the length of the driveshaft installed in the motor.-----I used to explain to folks that a long shaft motor has the same bits sticking below the transom as a short shaft motor.

 

[JimS123]

I am not sure that they market motors for 17" transoms.-----Many folks are confused by the term short and long shaft.-----It refers to the height of the boat transom.----Thus 15" motor is designated a short shaft and 20" is a long shaft.-----It is not some dimension on the motor itself.-----And it is not the length of the driveshaft installed in the motor.-----I used to explain to folks that a long shaft motor has the same bits sticking below the transom as a short shaft motor.

I have had several short shaft transom boats. Wood and Aluminum. The transoms varied in height from 16 - 17".

 

[Scott Danforth]

rough rule of thumb is 1" back for every 1/2" you raise the lower. so if you have 3" from the anti-cav plate to the bottom of the hull, you need a 6" set back. if you have 5", you need a 10" set back.

 

[crazy charlie]

Recently bought a Tohatsu 20hp 17 inch short shaft motor, the boat I have had a 20 inch transom. I’ve read lots of forums stating that installing an setback plate will make this set up work. Has anyone able to make this similar set up work? If so can I have some tips.

I would look into a kit that can be added to the shaft between the upper and lower to lengthen it.I have seen them used successfully.Charlie