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Porpoising Issue
#12405654
08/29/17 12:42 PM
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Joined: May 2011
Posts: 57
David W
OP
Outdoorsman
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OP
Outdoorsman
Joined: May 2011
Posts: 57 |
I figured I would ask the experts because I certainly am not one. I have a 22' Sea Hunt center console with a 200 HP mounted on an Atlas jack plate. The issue I'm having is when I get up on plane and get to 30-35 mph, the front of the boat will start bouncing (porpoising) and will not correct itself until I throttle back. I have it completely trimmed down and the jack plate is on it's lowest setting. It did it to me the other day when the water was like glass. What am I missing? I do have trim tabs that I can use to help resolve it but I'm pretty sure that is not what they are intended for. Is it a weight distribution issue? Any suggestions would be greatly appreciated. Thanks in advance!!
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Re: Porpoising Issue
[Re: David W]
#12405682
08/29/17 01:11 PM
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Joined: Dec 2014
Posts: 1,665
Muzzlebrake
Extreme Angler
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Extreme Angler
Joined: Dec 2014
Posts: 1,665 |
I wish I knew the perfect answer. I helped my boat by going to a 4 blade prop with less pitch and more cup to get more stern lift and moving as much weight as I could toward the front and middle. I think mostly it comes from boat hull design. The prop change allow me to get on pad about 10mph slower which is exactly what I needed. Funny thing is, I didn't lose any top speed and maybe gained 1-2 mph
From Genesis: "And God promised men that good and obedient wives would be found in all corners of the earth."
Then He made the earth round...and He laughed and laughed and laughed!
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Re: Porpoising Issue
[Re: David W]
#12405730
08/29/17 01:39 PM
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Joined: Apr 2017
Posts: 12,149
tmd11111
TFF Guru
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TFF Guru
Joined: Apr 2017
Posts: 12,149 |
I'm guessing you're running a 3 blade prop with a lot of rake and small blade surface area. While good for top speeds they tend to loose grip for lifting the bow at mid range speeds especially on CC's and bay boats with wide beams.. I had the same issue with my bay boat. Went to a stern lifting 4 blade and problem gone. Other advantages to a stern lifting 4 blade on a bay boat or cc is they will plane off faster and stay on plane at lower speeds. They usually will give better performance in the midrange as well. About the only trade off is in most cases you may loose 1-3 mph on the top end.
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Re: Porpoising Issue
[Re: David W]
#12405831
08/29/17 03:23 PM
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Joined: Jan 2005
Posts: 16,938
Pat Goff
TFF Guru
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TFF Guru
Joined: Jan 2005
Posts: 16,938 |
Get a set of electric trim tabs, your issues will end.
Pat Goff Seadrift TX
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Re: Porpoising Issue
[Re: David W]
#12405932
08/29/17 04:40 PM
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Joined: Aug 2009
Posts: 1,681
Capt Craig
Extreme Angler
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Extreme Angler
Joined: Aug 2009
Posts: 1,681 |
If you are running your jackplate at the lowest settings, try raising it. It can be a weight issue, but I have also seen it as a depth/thrust issue. With the amount of thrust much lower than the hull, it provides a lifting effect. Raising the jackplate places the thrust closer to the hull and therefore less lift of the bow is created as the force is inline.
In the event that all else fails, yes, trim tabs will resolve it.
Capt. Craig Copeland Licensed by the US Coast Guard
2019 Nautic Star 215 XTS Shallow Bay Boat Humminbird HELIX 12 CHIRP MEGA SI GPS G3N Nautic Star Boats Pro Staff (nauticstarboats.com) Redneck Fish'n Jigs Pro Staff (redneckfishn.com)
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Re: Porpoising Issue
[Re: David W]
#12405937
08/29/17 04:43 PM
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Joined: Jan 2005
Posts: 16,938
Pat Goff
TFF Guru
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TFF Guru
Joined: Jan 2005
Posts: 16,938 |
Sorry did not read your entire posting. You have trim tabs, use them. A little down will cure your bounces.
Pat Goff Seadrift TX
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Re: Porpoising Issue
[Re: tmd11111]
#12405991
08/29/17 05:13 PM
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Joined: Apr 2017
Posts: 12,149
tmd11111
TFF Guru
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TFF Guru
Joined: Apr 2017
Posts: 12,149 |
I'm guessing you're running a 3 blade prop with a lot of rake and small blade surface area. While good for top speeds they tend to loose grip for lifting the bow at mid range speeds especially on CC's and bay boats with wide beams.. I had the same issue with my bay boat. Went to a stern lifting 4 blade and problem gone. Other advantages to a stern lifting 4 blade on a bay boat or cc is they will plane off faster and stay on plane at lower speeds. They usually will give better performance in the midrange as well. About the only trade off is in most cases you may loose 1-3 mph on the top end. I guess I left out motor height plays a factor too
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Re: Porpoising Issue
[Re: David W]
#12406164
08/29/17 08:17 PM
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Joined: Jan 2013
Posts: 2,104
reelswift
Extreme Angler
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Extreme Angler
Joined: Jan 2013
Posts: 2,104 |
Use the trim tabs that is what they are designed to do.
Team LVS34 Captain WNB
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Re: Porpoising Issue
[Re: David W]
#12406295
08/29/17 10:04 PM
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Joined: Jun 2016
Posts: 6,854
V-Bottom
TFF Celebrity
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TFF Celebrity
Joined: Jun 2016
Posts: 6,854 |
A 50# sack of play sand up front may help
Texas Anglers Recognition Program TPWD Official Weigh Station,77563 Coastal Bend Weigh Team, Cert. Weigh Master USMC66'- www.troutsupport.com
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