Porpoising ?

[daviddsims]

I know I have asked before but just want to check before I buy smarttabs. I bought a glasstream 15 feet 120 hp mercruiser inboard boat. When i get on plane the front of the boat starts bouncing so bad that it feels like I am gonna start flying and I have to come to a stop to get it to quit. I know smaller boats have this problem but my last 17 feet boat with same motor and everything did not do this at all. I really havent tried shifting weight to the front but it really scared the crap out of me today and no matter how I trimmed it never got better. I just want to make sure that smarttabs will fix this and that there is nothing else wrong. Any suggestions?

 

[QC]

Re: Porpoising ?

Popoising is usually caused by weight balance . . . too much aft, and gets worse if you trim out. Trim tabs of any type if set and installed properly will definitely help, but you should probably work on the weight thing too. I had a 20 footer that I was VERY unhappy with until I got tabs, it sounds like yours is worse, so the weight thing is still a concern. I use adjustable tabs, but SmartTabs will be effective too.<br /><br />You could possibly have rocker in your hull. This would be that your hull is not flat but bowed slightly i.e. the bottom toward the stern is rounded upwards (opposite of hook). Still should be helped with trim tabs although this would be something "else wrong".<br /><br />Good luck!!!

 

[Moody Blue]

Re: Porpoising ?

Can't say for sure if tabs will help in your situation but they sure did the trick for me. I have a 14ft whaler style boat that is overpowered and hence the stern sits really low in the water at rest. To make matters worse, the console is positioned quit close to the stern so when I get in by myself the balance is WAY off. Had terrible porposing at anything past 1/2 throttle, engine tilted full down. Added a hydrofoil and that improved things quit a bit. Able to run 3/4 throttle now, engine still tilted full down. Removed the foil and installed tabs. Can now run full out AND trim the motor out where it should be. No more porposing. This thing flies now and is rock solid in the water. Turning is tight and smooth and hole shot is almost instant.