boat porpoising

[manten]

hi guys i have a 2001 sX180 skeeter with a 150hp yamaha  outboard now it has a fixed motor plate and it has a fin on the shsft that was put on it to help stop the porpoising but it still does it some when it try to power till it up. so is there any other way to stop it??? thanks for any help

[dave]

I moved both trolling batteries forward and always try to have my partner in the forward seat. (no pedestal) It helps a lot. Trimming down is still needed.  

[gim]

5 minutes ago, dave said:

always try to have my partner in the forward seat. (no pedestal)

Forward seat, no pedestal?  So are they riding on the floor?  I'm assuming you don't have a bass boat.  Having someone ride anywhere other than the bottom cockpit area is extremely unsafe.  The US Coast Guard stamp on my bass boat specifically says no riders outside the cockpit while the boat is on plane.

[dave]

Tracker Grizzly 1754.  The seat is literally on the floor.  I used to just have a throw cushion until until the seat idea dawned on me.  I can run with just me or another seated next to me...(fishing guide who routinely has two anglers) I just need to trim down more or come off the throttle a little more.  Whatever works.

[gim]

51 minutes ago, dave said:

Whatever works.

No, not really.  Because if you have a passenger riding where they aren't supposed to and you get into an accident, your insurance will not be covering it.  I am unfamiliar with the layout of a tracker grizzly so I have no idea if someone is riding where they aren't supposed to be.  In a bass boat, that means no passengers riding on the front or rear casting decks while the boat is on plane.

[WRB]

2 hours ago, manten said:

hi guys i have a 2001 sX180 skeeter with a 150hp yamaha  outboard now it has a fixed motor plate and it has a fin on the shsft that was put on it to help stop the porpoising but it still does it some when it try to power till it up. so is there any other way to stop it??? thanks for any help

Reset everything.

1. Check the Prop center line height to the planning pad height. Should be 3.50” with prop shaft parallel to the pad surface. If not remount the engine so it’s right.

2. Check the plane pad surface, it must be flat uneven surfaces.

3. Remove the fin!

4. Take everything out of the boat, livewells empty. 1/2 full tank of gasoline.

5. Test drive your boat and slowly trim up the engine until it’s on the pad, about 35 mph. Slowly increase power without more any more trim, your boat shouldn’t propose at this trim setting! If. It. Starts. To propose trim down a tick.    

Problem should be solved now. 

Start to add tackle and weight evenly, more weight to the stern area like a full tank of gasoline.

Tom

PS, what prop SST or aluminum and pitch?

 

[Susky River Rat]

3 hours ago, manten said:

hi guys i have a 2001 sX180 skeeter with a 150hp yamaha  outboard now it has a fixed motor plate and it has a fin on the shsft that was put on it to help stop the porpoising but it still does it some when it try to power till it up. so is there any other way to stop it??? thanks for any help

Did you just get this boat? Did you just recently change something and this started? If you are running lithium ion batteries it may be throwing off the weight distribution.  There have been some guys in here that have talked about this.

[DaubsNU1]

I'm no boat expert, but the advice from @WRB is very sound. 

 

Buddy of mine was big in to walleye boats...his advice:

1. PFD on, everything strapped down, passengers in their proper seats. 
2. Always start off slow
3. Always start with your motor trimmed all the way down
4. Once at full-throttle...slowly start to trim the motor up
5. You will gain speed and smooth out the ride
6. When the boat starts to porpoise just a little...trim it back down until smooths out
7. That's the "sweet-spot," best ride, & most speed

[rangerjockey]

Too much trim. Tuck the motor back in until it settles down, that's all the trim you can give it.

[Jig Man]

I don’t know if there is a fix.  Skeeters have that reputation.  I’ve never been in one that didn’t porpoise.

[MickD]

1 hour ago, DaubsNU1 said:

• Always start with your motor trimmed all the way down
• Once at full-throttle...slowly start to trim the motor up
• You will gain speed and smooth out the ride
• When the boat starts to porpoise just a little...trim it back down until smooths out
• That's the "sweet-spot," best ride, & most speed

This has always worked for me.  Even when I start at full throttle.  

[Captain Phil]

1 hour ago, Jig Man said:

I don’t know if there is a fix.  Skeeters have that reputation.  I’ve never been in one that didn’t porpoise.

 

I have owned at least a dozen bass boats from a 15' Terry Bass to an 80 mph Gambler.  I owned a 2000 Skeeter 185 with a Yamaha 150 for ten years.  It was one of the best boats I ever owned.  Porpoising is not unique to Skeeters.  All pad hull bass boats will porpoise under the right circumstances. The most common cause is too much trim.  Back when high performance bass boats first came out,  everyone wanted to create a "rooster tail" behind their boat.  We thought it looked cool, so we trimmed the motor up until the prop was nearly out of the water.   All we had at the time were two  blade props, which made porpoising worse. I can remember when we had to have the passenger run to the front of the boat just to get on a plane. Scary stuff!

 

Mounting the motor too high can cause porpoising.  Skeeter's come from the factory with the motor mounted where it should be, but you don't know what a previous owner might have done.  Another cause is too much weight in the rear of the boat.   Moving your junk around will help.   In rare cases you can find boats with a hook in the bottom.  Modern epoxy construction has pretty much eliminated that situation. 

 

In all my years of riding in bass boats, I find most owners of these boats don't know how to operate them correctly. Your boat will not run faster if you trim the motor too high.   Every boat has a balance point.  That balance point is a compromise between speed and comfort.  If you want a race boat, buy one.  If you want a boat to fish, trim the motor down and back off the throttle.  Your boat has more than two speeds. 

[Deleted account]

After you've ruled out all the setup and  weight distribution stuff, the correct answer is trim tabs.

[airshot]

16 hours ago, DaubsNU1 said:

I'm no boat expert, but the advice from @WRB is very sound. 

 

Buddy of mine was big in to walleye boats...his advice:

1. PFD on, everything strapped down, passengers in their proper seats. 
2. Always start off slow
3. Always start with your motor trimmed all the way down
4. Once at full-throttle...slowly start to trim the motor up
5. You will gain speed and smooth out the ride
6. When the boat starts to porpoise just a little...trim it back down until smooths out
7. That's the "sweet-spot," best ride, & most speed

That what works on my V bottom side console !!

[WIGuide]

The most common reason for proposing is over trimming. This can happen at any speed. As you increase trim the thrust angles up in turn pushing the bow up creating "lift". If the thrust is not sufficient to lift the weight of the bow and hold it, on most bass boats you'll get a proposing effect as there is enough to lift it a little but it can't sustain and the bow drops again. There are generally two ways to get out of it, either trim down, or power out if it. A beat up prop can make it happen more as they don't have as much grip. A 4 blade will generally be better than a 3 blade as well as the more blade area also provides more grip. If the boat is set up properly, the fin probably won't help since when on plane and trimming your cavitation plate is usually out of the water anyway.

[Cbump]

More speed or less trim. 

[CincyGus]

DaubsNU1 has the answer. Every boat with enough power to do 40mph will porpoise if you trim it too much. 

 

[BayouSlide]

3 hours ago, CincyGus said:

DaubsNU1 has the answer. Every boat with enough power to do 40mph will porpoise if you trim it too much. 

 

 

Even 30 mph...ask me how I know ??

[airshot]

On 4/25/2023 at 3:48 PM, CincyGus said:

DaubsNU1 has the answer. Every boat with enough power to do 40mph will porpoise if you trim it too much. 

 

Dont need to do 40 to porpoise...have done it at 25 mph....any boat that can actually get up on pkane can have a porpoising issue from to much trim or weight balance.!!!

[WRB]

This thread has a grey beard and solved over a year ago.

Tom