planing out

[dan500]

i have a 1987 stryker with a Johnson 150 and i can not get the hang of planing it out right. After the bow comes down it always start bouncing up and down. What am i doing wrong.

 

[paulie0735]

Re: planing out

Welcome to iboats, you are experiencing what’s commonly called porpoising. There are many causes including weight distribution, prop pitch and design, engine height and trim angle and a boat / engine mismatch and I’m sure there are a few more. Each or several can combine to result in a very unpleasant ride. <br />Give us all a little more information, there are many ways to address your problem but first things first………<br />What model engine do you have? (Year and model number)<br />Does it have trim, if so how are you using the trim?<br />What prop are you running?<br />What is your Wide Open Throttle RPM?<br />Is the engine fitted directly to the transom? If not is it fitted to a bracket and is the bracket fixed or adjustable?<br />We also need to know the installed height of the engine, to do this position the engine so the prop shaft is parallel with the bottom of the hull and measure how far below the hull it is.<br />All this info will help make it possible to get to the bottom of your problem. You may need a set of trim tabs to fix it but let’s make sure your setup is correct first.

 

[studlymandingo]

Re: planing out

All of the information Paulie mentioned will be pertinent to understand the cause of your particular porpoising dilemma. Two things that will alleviate it are, trimming the motor in; usually this will take bring the bow down so the motor is not pushing the bow skyward. If you have a higher powered motor, you often can accelerate through the bounce. I have installed Smart Tabs on my boat mainly for this reason. It completely corrected the porpoising, made the boat jump immediately on plane, and made it handle very well in chop, as well as through turns.

 

[Boatist]

Re: planing out

In general once on plane trim out until porpoising starts then trim in until it just stops. <br /><br />With big engines and high speeds everything is very critical. When the boat is at max power everything is critical. Jack plate, prop, trim tabs and weight distribution can all make a bit difference. Hull design and speed is big factors.

 

[dan500]

Re: planing out

I really appreciate all your help. I do not keep my boat at my house so I cant just go measure all that stuff. It is actually an 86 Stryker with a Johnson 150 mo# J5983224. The boat is 17 feet long. I have always thought that I may be just doing something wrong but now I am beginning to the there may be something wrong with the setup and that it should not be this hard to plane out. I try to trim all the way down and then when it planes trim up but then it starts the porpoising. It sounds like the motor revs up or something after it planes right before it starts porpoising. Maybe youll have some suggestions on my driving skills. this is really the first boat I have ever owned and Im 16 years old just trying to learn and love to fish.

 

[beezee28]

Re: planing out

You need to work with the trim after planing. Too much trim up and you will have porpoising. If you can take the boat out on a calm day and learn the adjustment of you tab and trim system. You will find a happy medium.

 

[paulie0735]

Re: planing out

Dan, At 17' with a 150 on the back the set up on your boat is critical and the driving skills even more so. You have a lot of performance available to you so spending the time to get it right is well worth it. Even if everything checks out fine, at least you know it right. As for your driving technique, take heed of the advise above re the use of your trim. Remember trim is an adjustment, its not designed to work over its full range on every boat, they make it work over a wide range to suit all the different boats not so you can use it all on every boat!

 

[dan500]

Re: planing out

Ill give it a shot and try to get the installed height of my engine. I really appreciate all of your help.