Notices

Porpoising Issues - Smart Tabs?

Old 07-15-2016, 11:29 AM
  #1  
Admirals Club Admiral's Club Member
Thread Starter
 
Join Date: Feb 2015
Location: New Orleans, La
Posts: 626
Default Porpoising Issues - Smart Tabs?

Added a T-Top to my 17' boat and now I'm fighting porpoising. With 3-4 people on board I cannot run over 25mph, no matter how I load the boat. I've moved some weight to the bow which helped - now i can run and trim the boat out with just he fiance and I on board, but once we add another person it's hell. Ken recommended a 4 blade prop for stern lift, but I do not want to change props just yet. Local boat shop(s) recommend adding tabs or a hydrofoil fin - I absolutely HATE the fin and that's my last choice.

Smart tabs seems like the best solution - cheapest, easiest, and nothing that needs to be constantly adjusted while someone else is running the boat. Will the smart tabs solve my issues or do I need to just go with either a prop ($350) or add Lenco 12v tabs ($600)


Nauticus PT9510-60 Smart Tab
https://www.amazon.com/Nauticus-PT95.../dp/B001DYUKRK

Self-Leveling Tabs (SLT)
http://www.bennetttrimtabs.com/self-leveling-tabs-slt/

I prefer the look of the Bennett's, and both can be had for ~$135
jvoisel is offline  
Old 07-15-2016, 11:40 AM
  #2  
Senior Member
 
Join Date: Aug 2013
Location: Charlotte Harbor, FL
Posts: 316
Default

I hate smart tabs with every bone in my body.

There isn't a replacement for a set of adjustable trim tabs. People without them seem to think that adjusting them is some sort of magic or its hard. I wont own a boat without them. They have so many uses from helping jump on plane faster to leveling out while on plane due to uneven weights in the boat.

A 4-blade prop with good stern lift will help for sure though.
devildog12210 is offline  
Old 07-15-2016, 11:46 AM
  #3  
Admirals Club Admiral's Club Member
 
Join Date: Oct 2014
Location: Kings Park, NY
Posts: 1,643
Default

If you are handy then go with the Smart Tabs, it will be your cheapest alternative $129. Pretty straight forward to install. 4 blade prop would be 2nd and then the most which is probably the best as you can also balance the boat without having to tell people to move over.
limshady88 is offline  
Old 07-15-2016, 11:47 AM
  #4  
HTJ
Senior Member
 
Join Date: Jun 2013
Location: Baytown, TX
Posts: 9,744
Default

Contrary to devil dogs experience I had a pair of smart tabs on a 21' WA back when and they did their job without fuss. Sure no adjustment on the fly capability but on a 17' you're not going to be making 50 mile runs offshore. In your scenario I wouldn't hesitate to use them.

Edit: My old rig would hold plane down to 13 MPH with the smart tabs and you couldn't make the hull misbehave.
HTJ is offline  
Old 07-15-2016, 11:55 AM
  #5  
Senior MemberCaptains Club Member
 
Join Date: May 2005
Location: Seattle, WA
Posts: 7,798
Default

Smart Tabs are terrible. Either install trim tabs or adjust the set up to avoid the porpoising.

Treat the problem, not the symptom
Tom W Clark is offline  
Old 07-15-2016, 11:55 AM
  #6  
GCC
Senior Member
 
Join Date: Feb 2010
Location: Mobile, AL
Posts: 5,664
Default

Why do you hate the hydrofoil? Every time Ive used them to solve the issues that youre having, it has worked. They even make one now that you dont have to drill holes in the cavitation plate to install (if thats your worry). If it were me, I would go with the Lenco tabs, but if budget was an issue, I would go with the foil considering its a 17ft boat. Lenco is a super great company and they have won me over in the past with their excellent customer service, therefor I just dropped 800.00 on a set of performance racing tabs for my big boat.
GCC is offline  
Old 07-15-2016, 11:57 AM
  #7  
Senior MemberCaptains Club Member
 
Join Date: May 2005
Location: Seattle, WA
Posts: 7,798
Default

Let's start with the basics...

What 17' Boat?

What motor?

What propeller is being used now?
Tom W Clark is offline  
Old 07-15-2016, 11:57 AM
  #8  
Senior Member
 
Join Date: Feb 2015
Posts: 3,396
Default Porpoising

"Smart" tabs are not held in high regard on THT. The world's smallest adjustable tabs might work if they fit on the transom but you will need additional controls, wiring, drill holes in your transom, etc. I would try a 4 blade prop before going through the time and expense of installing tabs. You can buy a used or new 4 blade aluminum prop on CL or eBay inexpensively, it's easily installed, lifts the stern which changes the entire attitude of the hull on plane, doesn't require adjustments or additional maintenance and you can easily remove and resell if it doesn't work.

PS You would be well advised to flow TW Clark's advice.

Last edited by LeakinLena; 07-15-2016 at 12:10 PM.
LeakinLena is offline  
Old 07-15-2016, 12:02 PM
  #9  
HTJ
Senior Member
 
Join Date: Jun 2013
Location: Baytown, TX
Posts: 9,744
Default

Originally Posted by Tom W Clark View Post
Smart Tabs are terrible.
School me please....Sure they're not the choice for a 28 Contender but on a smallish inshore boat why not. They are robustly built and in my one experience with them they were faultless.


OP I just reread your post and noted the 3 - 4 people part...ya need a bigger boat bro, or move the bigguns to the front
HTJ is offline  
Old 07-15-2016, 12:05 PM
  #10  
Senior Member
 
Join Date: Mar 2016
Location: Washington, NC
Posts: 1,075
Default

4 blade prop
Stevesmarsh is offline  
Old 07-15-2016, 12:18 PM
  #11  
Senior Member
 
Join Date: May 2013
Location: Goooooose Creek
Posts: 1,056
Default

I have run the Nautical Smart Tabs. They worked great for me but I went through 3 shock absorbers in 4 years. They were all replaced under warranty. They were friendly and very helpful and even gave me a spare when I voiced my concern about the warranty ending.

For your situation I would want adjustable tabs. You may only need a small bump to keep the bow down. Once you find the sweet spot you wont have to move them till next trip.
friogatto is online now  
Old 07-15-2016, 12:46 PM
  #12  
Admirals Club Admiral's Club Member
Thread Starter
 
Join Date: Feb 2015
Location: New Orleans, La
Posts: 626
Default

Originally Posted by Tom W Clark View Post
Let's start with the basics...

What 17' Boat?

What motor?

What propeller is being used now?
2016 Sportsman Island Reef 17
Yamaha F90
Turbo Quest 13-1/8 x 18

Took a while to find a prop I was happy with. I tried 6-7 Powertech's, hated every one. Including the SCD3. Now I'm debating a SCD4, which is their sternlifting prop but still feel it would be a waste of money - as I was not happy with ANY of the other Powertech's I have tried.

I can get Solas props at dealer cost - considering buying a Titan HR4 13x17 and trying that, but if it does not work then I have to sell it, buy another, etc. Not looking forward to being stuck with a few more props for testing.
jvoisel is offline  
Old 07-15-2016, 12:47 PM
  #13  
HTJ
Senior Member
 
Join Date: Jun 2013
Location: Baytown, TX
Posts: 9,744
Default

What hole is your motor mounted in?
HTJ is offline  
Old 07-15-2016, 12:48 PM
  #14  
Member
 
Join Date: Apr 2016
Posts: 93
Default

Get the fin! Don't be a hater. They are easy to install, adjustable, and work great! Got my old Proline 17 to plane at 11 knots with the Sting ray fin!
Canoe Sailor is offline  
Old 07-15-2016, 12:50 PM
  #15  
Admirals Club Admiral's Club Member
Thread Starter
 
Join Date: Feb 2015
Location: New Orleans, La
Posts: 626
Default

Originally Posted by HTJ View Post
What hole is your motor mounted in?
Motor is mounted in the top hole.
Came from the factory on the 2nd hole, moved it up as per Ken's suggestion when we were prop testing. It did improve performance, but I was not having the porpoising issues at the time.
jvoisel is offline  
Old 07-15-2016, 12:59 PM
  #16  
Senior Member
 
Join Date: Nov 2014
Location: N.E. Florida
Posts: 891
Default

Originally Posted by jvoisel View Post
Added a T-Top to my 17' boat and now I'm fighting porpoising.
I think everybody is skipping over this part.

Big heavy T-Top on a small boat changed the COG drastically?



Seems it would have the opposite effect, but I guess it depends on mounting location.

A foot or two one way or the other could cause huge changes in how the boat rides.

Pics?

Edit: looking at sig pic, seems you would be more likely to bow steer than porpoise.

Last edited by Cucumber; 07-15-2016 at 01:01 PM. Reason: looked at sig pic
Cucumber is offline  
Old 07-15-2016, 01:02 PM
  #17  
HTJ
Senior Member
 
Join Date: Jun 2013
Location: Baytown, TX
Posts: 9,744
Default

Without getting confused on semantics, top hole = motor all the way down, is this were you are? If so that may well be the root source of your porpoising. In a nut shell just about any boat motor combo should have the motor as high as possible without blowing out.

Motor too low is contributor numero uno to porpoising problems
HTJ is offline  
Old 07-15-2016, 01:06 PM
  #18  
Admirals Club Admiral's Club Member
Thread Starter
 
Join Date: Feb 2015
Location: New Orleans, La
Posts: 626
Default

Originally Posted by Canoe Sailor View Post
Get the fin! Don't be a hater. They are easy to install, adjustable, and work great! Got my old Proline 17 to plane at 11 knots with the Sting ray fin!
Jsut always hated them. May buy one, and give it a shot - since they're no-drill but I REALLY hate the damn things.

Originally Posted by Cucumber View Post
I think everybody is skipping over this part.

Big heavy T-Top on a small boat changed the COG drastically?



Seems it would have the opposite effect, but I guess it depends on mounting location.

A foot or two one way or the other could cause huge changes in how the boat rides.

Pics?

Edit: looking at sig pic, seems you would be more likely to bow steer than porpoise.
Top is mounted in the only place I could fit it - it's as far back as it'll go before hitting the console, and I can't move it forward because then it does not fold down enough to go under my cover. (fish master folding - and it's only about 100#)
Attached Images  
jvoisel is offline  
Old 07-15-2016, 01:07 PM
  #19  
Admirals Club Admiral's Club Member
Thread Starter
 
Join Date: Feb 2015
Location: New Orleans, La
Posts: 626
Default

Originally Posted by HTJ View Post
Without getting confused on semantics, top hole = motor all the way down, is this were you are? If so that may well be the root source of your porpoising. In a nut shell just about any boat motor combo should have the motor as high as possible without blowing out.

Motor too low is contributor numero uno to porpoising problems
No, sorry, bottom hole. Motor all the way up.
jvoisel is offline  
Old 07-15-2016, 01:09 PM
  #20  
Senior Member
 
Join Date: Nov 2014
Location: N.E. Florida
Posts: 891
Default

Originally Posted by jvoisel View Post
Jsut always hated them. May buy one, and give it a shot - since they're no-drill but I REALLY hate the damn things.



Top is mounted in the only place I could fit it - it's as far back as it'll go before hitting the console, and I can't move it forward because then it does not fold down enough to go under my cover. (fish master folding - and it's only about 100#)
Did the boat porpoise before you added the t-top?
Cucumber is offline  

Thread Tools
Search this Thread