Boat porpoising

N

NewfieDan

Petty Officer 1st Class
Joined
May 8, 2011
Messages
383
Had my new to me boat out a couple of times and noticed something strange.

When running at just above cruising speed to WOT the boat porpoises until I trim almost all the way down, almost to the point of plowing water. At first I thought it was the swells and waves creating the action but yesterday it was flat calm.

I've used the boat exclusively on salt water. The boat itself is a '07 Rinker with a Merc 5.0 Alpha one drive. The prop is 14.5 x 19 Pitch.

My last boat never did this so I am wondering what may be causing this. My parents boat also never did this.

Your thoughts?
 
NYBo

NYBo

Admiral
Joined
Oct 23, 2008
Messages
7,107
Re: Boat porpoising

Weight distribution. Your current boat is apparently more stern-heavy than you r last one or your parent's.

Give my regards to Brigus!:)
 
B

Bamaman1

Lieutenant Commander
Joined
May 15, 2011
Messages
1,895
Re: Boat porpoising

If you get a set of adjustable hydraulic trim tabs, you can easily solve the problem. They're around $475, and very easy to install.
 
NW Redneck

NW Redneck

Chief Petty Officer
Joined
Jul 30, 2006
Messages
643
Re: Boat porpoising

Yup, sounds like you're stern heavy. Try loading as much gear as you can to the front and see if it helps. Bamaman's suggestions of trim tabs is a good one too. If you don't want to go to the expense and trouble of adjustable tabs, Nauticus Smart tabs are a great product. I have these on my boat (18.5' Cal-Glass w/175hp I/O) which is a little stern heavy and they greatly improved bow rise while getting on plane and almost totally eliminated porpoising.
 
jayhanig

jayhanig

Master Chief Petty Officer
Joined
Jun 27, 2010
Messages
836
Re: Boat porpoising

Ditto on the Smart Tabs. Mine have eliminated slow speed wander and I plane out very easily without porpoising. I only paid $160 or so for them in stainless steel.
 
N

NewfieDan

Petty Officer 1st Class
Joined
May 8, 2011
Messages
383
Re: Boat porpoising

Thanks for the input. Any idea where I can find more info onthe smart tabs?

I've never heard of them. it sounds like they are definitley worth looking into.
 
ezmobee

ezmobee

Supreme Mariner
Joined
Mar 26, 2007
Messages
23,767
Re: Boat porpoising

NewfieDan said:
Thanks for the input. Any idea where I can find more info onthe smart tabs?

I've never heard of them. it sounds like they are definitley worth looking into.
Click to expand...

Oh come on man, don't make us bust out one of those condescending "let me Google that for you" links :p:p

The company that makes them is Nauticus. http://www.nauticusinc.com/
 
You must log in or register to reply here.
Top