I need help with a porpoising problem I need help with a porpoising problem
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    I need help with a porpoising problem
from rswright11 #11722  
7/14/2010 9:40:05 PM


 I couldn't get my boat to plane out so I added a SE Sport hydrofoil to it and noticed the pin was missing on the mount so I added one of those. I took my boat out today and got it to plane out when I put the throttle all the way down while barely trolling but once it got on plane, it porpoised bad for about 10-15 seconds then smoothed out. I thought the hydrofoil would stop it from doing it. Before I changed lower unit, it didn't do it after planning out. What else can I try?

Thanks in advance!

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   More info from rswright11 #11722  7/14/2010 10:23:06 PM
I have a 16ft Skeeter with a Johnson 140HP. No jack plate.

   Hydrofoil from Big Erk #10974  7/15/2010 12:38:03 AM
The hydrofoil only helps your boat get up on plane easier. After you're up on the pad, the hydro foil is completely out of the water and serves no purpose. Porpoising occurs when your motor is trimmed out/up too far for the speed you are running. The slower the speed the more your outboard needs to be trimmed in/down. The faster the speed the more you can trim your motor out/up for faster running. From what info you've given it sounds as if you might be over propped or running a higher pitch prop than what you need. Hope this helps.

   Forgot from Big Erk #10974  7/15/2010 12:40:46 AM
I forgot to ask, what "pin" are you referring to? Is it the long pin that mounts horizonally near the trim motor? Just asking.

   prop and pin from rswright11 #11722  7/15/2010 8:10:00 AM
The pin is the horizontal one that you can put in a number of holes that look like a half moon shape to stop the motor. The pin is like 12" long. The prop might be my problem. Since I had to get a new lower unit, I didn't want my bent prop to mess up the seals in the lower unit I just replaced so I had it reconditioned and tuned. It may not match my boat but I have no idea what they tuned it at or what's it suppose to be tuned at.

   Know your boat from flipnswim  7/15/2010 10:02:42 AM
I don't know about the I-Class or the FX, but the ZX and SX used to have a tendency to porpoise at lower speeds. It was just a matter of being aware and throttling through the range where the bouncing lived. This is not a knock on Skeeter, they make fantastic boats. Every line has it's own idiosyncrasies.

   older boat from rswright11 #11722  7/15/2010 10:12:01 AM
Mine is a 80's Sport Wrangler SW-150 XSP.

   Pin from SMS #11748  7/15/2010 11:04:36 AM
Unless the engine hits the transom when trimmed all the way in, you don't need that pin at all. It may be keeping your motor trimmed out too far at take-off.

   High speed Porpoise from Hydrasports196 #11880  7/15/2010 11:44:20 AM
My boat was terrible at full WOT.I tried all the tricks. Nothing worked to eliminate it. I installed some Nauticus Smart tabs. Best move I could ever make. Fast to plane, will plane at very low speeds, no porpoise at top end.
I gained about 2 mph.
You must remove the hydrofoil, can't run them together

   options from rswright11 #11722  7/15/2010 1:32:45 PM
I'm going to check the pitch and size of the prop I have on the boat. All I know is that it is a Raker prop. I'm going to call the place that tuned it with what kind of outboard and boat I have, to see if I have the right prop. It wouldn't surprise me if the dude sold me the boat with the wrong prop. The lower unit was crap when I bought it and he never mentioned that. I've never seen smart tabs on a bass boat. I'd hate to be the first but it is not operational the way it is now. As far as the pin goes, I couldn't get it to plane at all the last time I had it out and that was without the pin or hydrofoil. Maybe I can just try it with the hydrofoil and no pin.

Thanks guys for all your help! I swear it seems like I fix one issue with this thing and two more pop up.

   couple of questions before you do all that from Beartrap   7/15/2010 6:40:31 PM
suspect from your comments that you are a new boater.....do you have power trim on this boat? if so are you trimming your motor all the way down when you take off?then bumping the trim up a little as you get up on plane....if you don't have power trim, you have got to set the pin underneath your motor in right place or you won't ever cure this problem...I'm guessing one or two notches from the bottom will probaly be about right....

Beartrap also I doubt seriously if the prop has anything to do with porposing problem...

Edited 7/15/2010 7:19:33 PM

   you are correct from rswright11 #11722  7/16/2010 6:43:36 PM
I am a new boater. I have power trim and I start with the motor down. I talked with the pro shop today and they told me to try and drop the motor if I can or get a 6 inch jack plate and that would help some with the porpoising. He said his first boat was a Starfire 16ft and that would porpoise too. He said Skeeters have always had an issue with that. As far as the hole shot is concerned he told me to drill out the holes a little bigger and that should take care of that problem. I'm going to give it all a try and see what happens. Thanks for everything!

   rs....you need a little more seat time from Beartrap   7/17/2010 7:51:04 AM
 those 16 ft/150 hp boats were overpowered and all of them had handling issues..and most of them porpoised at low spees.....spend your money on gas, learning to drive it for next month or so..if you are at ramp and see somebody with a high performance boat(Bullet-Allisoncraft etc) don't be afraid to ask for advice or even for them to drive your boat for you and tell you what might help it....

I had a 17 ft Allison rated for 115 with a 150 on it and that boat porpoised at a certain speed and there was nothing you could do about it except not drive it at that speed...I highly suspect that is case with your boat...

   SMS has it right on the mark....remove the pin and throw it away. from humminbird #11206  7/18/2010 3:50:11 PM
 It sounds like your engine is already too far trimmed out. Remove the pin and get your tail (trim all the way down) up under your boat. With trim/tilt, you can throw the pin away. You don't need it and it is probably causing your trouble.


   Update from rswright11 #11722  7/20/2010 1:55:16 PM
 I drilled the holes in from of the blades 2 sizes bigger than they were (recommendation from my prop guy) and that fixed my planing problem while moving. The porpoising issue may be here to stay. Prop guy told me his first boat was a 16ft Starfire and that had a porpoising issue as well. He said Skeeter is known for that. He suggested a 6" jack plate to help the issue but it won't go away totally. Bumping the trim seemed to make it stop a lot faster so I think I'm going to put more seat time in and deal with it. Unless I see a used jack plate cheap somewhere. Thanks for all you guys help!!!!

Tight lines!!!!

   rswright11, try this from humminbird #11206  7/22/2010 5:18:57 PM
I had a 16 ft boat that porpoised really bad. I bought an aluminum wedge that bolted on the cavitation plate from Bass Pro Shop many years ago (1983). Not sure they sell them today. However, this wedge greatly lifted the boat and eliminated porpoising. The wedge was above 5" wide and was tapped from 0" to 1 1/4 or 1 1/2" at the rear. Its function is to lift the transom and it works, unlike the hydrofoil, because it remains under the water at WOT. Check it out. You could have one fabricated. Forgot to mention that the wedge takes the place of the trim tab. Thus, no holes are needed to mount it...just use the bolts for the replaced trim tab.


Edited 7/22/2010 5:20:53 PM

Edited 7/22/2010 6:40:41 PM



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