Reply
 
Thread Tools Search this Thread Display Modes
 
Old 03-17-2019, 11:49 PM   #1
Guru
 
Arthurc's Avatar
 
City: Seattle
Country: USA
Vessel Name: Sea Bear
Vessel Model: Kadey-Krogen 54
Join Date: Sep 2016
Posts: 522
Trim Tabs for 12í RIB?

I have trim tabs on both my old rib and my bullfrog, the new rib has significantly more horsepower but the bow comes way up when jumping on a plane and it porpoises a bit at low speed plane. Are trim tabs really that effective, I for the life of me canít seem to think of anything else different? If so what brand do you like best.

Thanks!
__________________
Advertisement

__________________
Kadey-Krogen 54
Arthurc is offline   Reply With Quote
Old 03-18-2019, 12:42 AM   #2
Guru
 
HopCar's Avatar
 
City: Miami Florida
Vessel Name: Possum
Vessel Model: Ellis 28
Join Date: Aug 2011
Posts: 4,360
I’ve been playing with the problem of bow rise and I’ve decided you need some planing surface aft of the transom. Fixed or spring type trim tabs solve the problem nicely. I don’t know why more small boats aren’t designed with surface area aft of the transom.
__________________

__________________
Parks Masterson
HopCar is offline   Reply With Quote
Old 03-18-2019, 01:21 AM   #3
Guru
 
Comodave's Avatar
 
City: Au Gres, MI
Country: US
Vessel Name: Never Say Never
Vessel Model: President 41 DC
Join Date: Jul 2015
Posts: 5,371
I added the spring type of tabs, cannot remember the name of them, on a previous RIB and they worked well.
Comodave is offline   Reply With Quote
Old 03-18-2019, 05:09 AM   #4
Guru
 
Keysdisease's Avatar
 
City: South Florida
Country: USA
Join Date: Sep 2014
Posts: 701
Some small RIBS benefit from a hydrofoil on the outboard. Doelfin, Stingray, Whaletail, choose your poison I don't have experience with any of them but when I see one on a RIB I have always asked how they work and the answer has almost always been something like "good." Downside is there is no adjustment, so they work or they don't but there is no tweak. They may also shave a little speed off top end and get in the way

There are three types of trim tabs for a small RIB to consider

Fixed: Cheapest, adjustable but not underway, includes "wedges"

Spring Loaded: Bennett and Nauticus and maybe others, offer more tab when you need it to get on plane, and less as speed increases, some adjustability but not underway

Electric: Bennett and Lenco and others, fully operational trim tabs that are just the actuators, planes and control at helm. Best and most expensive

There are also "intercepters." These sound just wrong but really work. I don't believe any of the manufacturers make any small enough for a RIB, but fixed intercepters would be easy to fabricate and would be adjustable, but not underway.

Keysdisease is offline   Reply With Quote
Old 03-18-2019, 06:27 AM   #5
Guru
 
Arthurc's Avatar
 
City: Seattle
Country: USA
Vessel Name: Sea Bear
Vessel Model: Kadey-Krogen 54
Join Date: Sep 2016
Posts: 522
Thanks all, I think I’ll give the Nauticus a try, plus ordered the Davis hydrofoil, it’s likely less effective than the larger ones but I need to be able to walk around the boat so a large fin like the whaletail is out.
__________________
Kadey-Krogen 54
Arthurc is offline   Reply With Quote
Old 03-18-2019, 07:10 AM   #6
Guru
 
Maerin's Avatar
 
City: East Coast
Country: USA
Vessel Name: M/V Maerin
Vessel Model: Solo 4303
Join Date: Jun 2013
Posts: 808
Quote:
Originally Posted by Arthurc View Post
Thanks all, I think Iíll give the Nauticus a try, plus ordered the Davis hydrofoil, itís likely less effective than the larger ones but I need to be able to walk around the boat so a large fin like the whaletail is out.

Addition of a Doel-Fin changed our 10-6 Caribe with a 15 HP from bow-high & unstable to quick-planing and steady. No more bow attitude. With only one person, it was almost scary. EZPZ install, no maintenance. A friend had the gas shock tabs on their AB, mostly they were replacing the springs. Rarely functioned as intended.Great concept, lousy implementation.
__________________
Steve Sipe
Selene 4303 Maerin
http://maerin.net
Maerin is online now   Reply With Quote
Old 03-18-2019, 07:21 AM   #7
Guru
 
Keysdisease's Avatar
 
City: South Florida
Country: USA
Join Date: Sep 2014
Posts: 701
I would try the hydrofoil first, you may not need tabs if it works



Quote:
Originally Posted by Arthurc View Post
Thanks all, I think Iíll give the Nauticus a try, plus ordered the Davis hydrofoil, itís likely less effective than the larger ones but I need to be able to walk around the boat so a large fin like the whaletail is out.
Keysdisease is offline   Reply With Quote
Old 03-18-2019, 07:40 AM   #8
Guru
 
Arthurc's Avatar
 
City: Seattle
Country: USA
Vessel Name: Sea Bear
Vessel Model: Kadey-Krogen 54
Join Date: Sep 2016
Posts: 522
Yep, I plan on installing it first, plus I’m a bit worried the tabs will monkey with the airmar transom mount transducer which I have yet to install.
__________________
Kadey-Krogen 54
Arthurc is offline   Reply With Quote
Old 03-18-2019, 07:41 AM   #9
Guru
 
City: Hampton, va
Country: USA
Vessel Name: Didi Mau
Vessel Model: 2003 Ocean Alexander 456
Join Date: Jul 2015
Posts: 907
I have a Diel fin

Quote:
Originally Posted by Arthurc View Post
Thanks all, I think Iíll give the Nauticus a try, plus ordered the Davis hydrofoil, itís likely less effective than the larger ones but I need to be able to walk around the boat so a large fin like the whaletail is out.
On my 12 foot dinghy with 15hp engine. It came with the boat when bought three years ago, so I donít know about performance before install. My boat gets on plane with four adults and seems stable and under control at all speeds.

These characteristics may come from the dinghy versus the fin. The dinghy is a west marine 350 with 19 inch tubes.

Gordon
Gordon J is offline   Reply With Quote
Old 03-18-2019, 07:50 AM   #10
Guru
 
hmason's Avatar
 
City: Stuart FL
Country: USA
Vessel Name: Magic
Vessel Model: Grand Banks 46 Europa
Join Date: Aug 2013
Posts: 2,235
Quote:
Originally Posted by Arthurc View Post
Thanks all, I think Iíll give the Nauticus a try, plus ordered the Davis hydrofoil, itís likely less effective than the larger ones but I need to be able to walk around the boat so a large fin like the whaletail is out.
I have the Nauticus and Iím pleased. Be aware that they say not to use a hydrofoil with the tabs. I had a foil and had to remove it.
__________________
Howard
Magic, 1996 Grand Banks Europa
Westport, CT and Stuart, FL
hmason is offline   Reply With Quote
Old 03-18-2019, 09:35 AM   #11
Guru
 
Keysdisease's Avatar
 
City: South Florida
Country: USA
Join Date: Sep 2014
Posts: 701
Originally Posted by Arthurc
Thanks all, I think Iíll give the Nauticus a try, plus ordered the Davis hydrofoil, itís likely less effective than the larger ones but I need to be able to walk around the boat so a large fin like the whaletail is out.


Quote:
Originally Posted by Keysdisease View Post
I would try the hydrofoil first, you may not need tabs if it works
While the Nauticus product has been around for awhile, I think the Bennett spring loaded units to have cleaner look and are more robust. I may not be entirely objective:
Attached Thumbnails
Click image for larger version

Name:	smart_tabs-1-1-495x400.jpg
Views:	17
Size:	5.0 KB
ID:	86508  
Attached Images
 
Keysdisease is offline   Reply With Quote
Old 03-18-2019, 10:08 AM   #12
Guru
 
City: Northport
Country: USA
Join Date: Aug 2015
Posts: 1,396
Somnetimes just changing the hieght of the motor on the transome will give better results.
I have had great results with the Nauticus tabs on 3 different RIBS now - some fairly high powered. They were adjustable enough to alleviate bow lift and porpoising on one RIB which had a larger tendency to porpoise without them.
Never have I favored attachments to outboards or outdrives as they always seem to lend at least one negative attribute.
smitty477 is offline   Reply With Quote
Old 08-08-2019, 01:03 PM   #13
Newbie
 
City: Seattle
Country: US
Join Date: Aug 2019
Posts: 1
Trim tab solution

Arthur, were you able to get your bullfrog to keep the bow down. I have a 10 foot bullfrog that came with a boat I just bought. It has a dolefin and smart tabs and still is bow up. I am going to remove the dolefin and add pressure to the smart tabs, but that is desperation. Was hoping maybe you found a cure.

Bill
wherman is offline   Reply With Quote
Old 08-08-2019, 01:25 PM   #14
Guru
 
Join Date: Oct 2007
Posts: 850
Doel Fins work well and are inexpensive and easy to attach to the motor.
Chrisjs is offline   Reply With Quote
Old 08-08-2019, 01:39 PM   #15
Guru
 
Arthurc's Avatar
 
City: Seattle
Country: USA
Vessel Name: Sea Bear
Vessel Model: Kadey-Krogen 54
Join Date: Sep 2016
Posts: 522
I used motor mount fins on my new rib, they work great. On the bull frog it’s got smarttabs which also work
__________________
Kadey-Krogen 54
Arthurc is offline   Reply With Quote
Old 08-08-2019, 02:01 PM   #16
Guru
 
caltexflanc's Avatar
 
City: North Carolina for now
Country: USA
Vessel Name: Small Incentive
Vessel Model: Boston Whaler 130 Sport
Join Date: Aug 2011
Posts: 5,184
I use the hydraulic trim of the engine itself to fine tune these things just fine with a push of the button on the throttle lever. Weight and weight distribution vary so no one setting will do for every situation.

On wider, bigger boats, trim tabs make more sense. Of course if you can't easily adjust the trim of your outboard, then some sort of tab is useful. My problem is that we use the boat to go to the beach, and tabs get somewhat in the way of reboarding even on our friend's 22' Cobia; on a 12 foot RIB, I don't see it.
__________________

__________________
George

"There's the Right Way, the Wrong Way, and what some guy says he's gotten away with"
caltexflanc is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





All times are GMT -5. The time now is 03:40 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012
×