Crazy boat

[SpinnerBait_Nut]

OK, this boat has done this for a long time, but I want to find out what is doing it and what I have to do to fix it.<br /><br />It is a 1986 16' Bassmaster with a 115Mariner on it.<br /><br />I have no problem getting on plane, but when I start trimming the engine up, it <br />1. Starts to porpoise, <br /><br />2. if I keep trimming it up, it will quit that, but the rear of the boat gets real squirrelly, as in switching from side to side, violently.<br /><br />Now do I have a weight problem, as in not enough up front, or not enough on one side?<br /><br />I do weigh in at about 300lbs.<br /><br />Don't know if it will do the twitching stuff when wifey pooh is with me cause I never trim it that far, in fear of dog house, but it will start to porpoise at which time I will trim it back down to stop it.<br /><br />Any ideas would be appreciated.

 

[catfish1]

Re: Crazy boat

i dont know what it is spinner, (maybe a hook?) but if your takin it to the ozarks with you in three weeks you could give some demo's and i'll bet someone will figure it out! if not, it will sure make conversation

 

[neumanns]

Re: Crazy boat

Sounds like chin walk possably. when it gets up on the pad it starts falling of side to side. Just my guess lets see what the experts say. If that is what it is I do not have a clue how to fix it.

 

[CalicoKid]

Re: Crazy boat

SBN, have you checked for excessive play in your motors pivot points or steering linkages?

 

[SpinnerBait_Nut]

Re: Crazy boat

Kid, I have noticed that the motor mounts are loose. But don't think they are that loose.<br />You can just barely move the engine by hand.

 

[DJ]

Re: Crazy boat

SBN,<br /><br />Porpoising (bow up and down oscillations) is typically caused by to much weight aft.<br /><br />Chine walking is typically due to hull design or other causes such as prop torque, eight imbalance, etc.<br /><br />Your loose engine mounts are not helping your chine walking issue. The engine can move side to side thus transferring power from one side to the next.<br /><br />Super hi-perf. boats use very hard engine mounts to fight that issue.

 

[SoulWinner]

Re: Crazy boat

In a word, Smart Tabs. Ok, thats two words, but they are great. Check out the threads on them. I love mine. I didn't think I could be happier with my boat when I bought it, until I put the Smart Tabs on. WOW, what a dif

 

[DJ]

Re: Crazy boat

SBN,<br /><br />Agree with SW. Those will definetely help. But, you still need to tighten up that engine.

 

[SpinnerBait_Nut]

Re: Crazy boat

Yea djohns, but don't that call for the engine to be removed to replace them?

 

[DJ]

Re: Crazy boat

SBN,<br /><br />Sometimes yes, sometimes not. Not being that familiar with the mounting mechansim on a Mariner, I can't say.<br /><br />Try to tighten them up first. Regardless, it has to be dealt with. Or, stay under the speeds that cause you problems. A chine walking boat can "get away from you" pretty quickly.

 

[SpinnerBait_Nut]

Re: Crazy boat

thanks dj, I will post in mariner to get a feel of motor mounts.

 

[Jdeagro]

Re: Crazy boat

I agree that the motor should be tight, however the porpoising is typical of stern loaded, power boats. The balance point is in the last 30% of the boat and this allows the boat to rotate bow high because there is more boat and LESS weight forward. Every time there is a small force (pressure) to lift the bow, it goes up. Trimming the motor down allows the propeller to lift the stern (pushing the bow down) to resist the bow from coming up. The problem is that with constant strn lift (and resulting bow down pressure) the boat runs slower, and bow steers. <br /><br />Once the higher speeds are achieved, the boat runs high on the center of the boat with no outboard stability. It then rocks side to side (chine walks), but this is rare unless the boat is doing 50+mph. Keep in mind that the boat is balancing on an axis and can rotate in any direction. Front to back or side to side. Your boat is a very good candidate for Smart Tabs.