Jon boat porpoising

cvtech1

Petty Officer 1st Class
Joined
Aug 16, 2009
Messages
277
I have a 14ft Jon with a 25hp Johhny it has a hydrofoil. I have just noticed it seems to be porpoising alot, not sure if it always have been but just learned what porpoising is. When I reduce speed no problem, is there a easy solution for this? Anyone?
 

capt sam

Master Chief Petty Officer
Joined
Jan 14, 2009
Messages
878
Re: Jon boat porpoising

move as much weight as you can up front, fuel tank, batteries, cooler. Make sure the motor is pinned in close to the transom.
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,417
Re: Jon boat porpoising

Ayuh,... Get rid of the whaletail,+ move the motor to a lower pin setting...
 

nam6869usmc

Petty Officer 2nd Class
Joined
Sep 3, 2009
Messages
115
Re: Jon boat porpoising

Mine's "Porpoising" also, but when I trim motor all the way ((down)) & then tap my "Lenco Trim Tabs" Bow Down about 3 times it stops. I'm over HP with a 50HP on this 14"(running a 40HP Cowling);), it's HP rating is 45 and it also has a CMC Tilt bolted on the back.(Heavy). I bought this boat with the Lenco's Trim Tabs on it and with what I know now, I would recommend Smart Tabs or Lenco's on any boat..
DSC01084.jpg

DSC01088.jpg

P.S. also running a Solas 4 Blade Prop.....
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: Jon boat porpoising

nam6869usmc , you are definately tail heavy.
 

arks

Lieutenant Commander
Joined
Nov 7, 2002
Messages
1,962
Re: Jon boat porpoising

move as much weight as you can up front, fuel tank, batteries, cooler. Make sure the motor is pinned in close to the transom.

What he said!

I have a 14 foot Jon (25 HP) with a side console. To settle it down I had to do some serious weight-shifting. I moved the trolling battery forward and store the spare gas tank and anchor in the bow. That did the job.

Interior002.jpg
 

cvtech1

Petty Officer 1st Class
Joined
Aug 16, 2009
Messages
277
Re: Jon boat porpoising

Thanks for the advice, I do believe that my motor is not in the lock down position first of all because it tried to raise up in reverse. Oops, just learned that it would lock down. The previous owner did not know that because he had a rubber tie down strapped to it. I will move more things up front as I start to convert it for storage. My hold boat is open, any ideas?
 
Top