Adding trim tabs

TIDE

Active Member
Joined
Jan 9, 2022
Messages
28
Reaction score
4
Points
3
Location
Chesapeake Bay, Maryland
Model
Seafarer
My 94’ seafarer did not come with trim tabs and am looking into adding Bennett tabs, preferable ones with the autotrim controls. Has anyone added them and seen an improvement? Main reason I’m looking into them is to lessen roll while trolling and moving around the boat along with improvement of how it handles in general.
 

seasick

Well-Known Member
Joined
Aug 19, 2008
Messages
9,141
Reaction score
1,310
Points
113
Location
NYC
I suspect that if trolling fairly slowly, trim tabs won't make much of a difference. They are not stabilizers even with auto trim.
At speed they can help to a point and can help if the boat is listing at speed but if you have waves abeam, the hull is going to roll.
 

DennisG01

GreatGrady Captain
Joined
Sep 1, 2013
Messages
6,817
Reaction score
1,208
Points
113
Location
Allentown, PA & Friendship, ME
Model
Offshore
Yup, trim tabs have no effect on roll (or pitch) at slow speeds. But they would have a tremendous impact on stability, ride comfort, hole shot and fuel economy at speed.

The way to solve help roll at slow speeds is with a wider-beam boat.

The way to solve roll issues at slow speeds is by installing a SeaKeeper. www.seakeeper.com :)
 
  • Like
Reactions: enfish

TIDE

Active Member
Joined
Jan 9, 2022
Messages
28
Reaction score
4
Points
3
Location
Chesapeake Bay, Maryland
Model
Seafarer
Thanks for clarifying. So it will help with the boat leaning to one side or the other while at speed? One of my passengers (mother-in-law) is a bit on the heavier side so each time she sits on the boat or moves it causes the boat to lean to one side and is not as enjoyable to take out.It's a pain to drive really because the boat is all over the place from the weight difference. Hoping trim taps would help with that rather than having the conversation with my wife as to why her mom can't come on the boat LOL.

Just curious - how much more speed and fuel savings do you get with trim tabs?
 

DennisG01

GreatGrady Captain
Joined
Sep 1, 2013
Messages
6,817
Reaction score
1,208
Points
113
Location
Allentown, PA & Friendship, ME
Model
Offshore
I probably shouldn't have used "fuel economy" in the same line as "tremendous". It will help fuel economy, for a number of reasons, but it's not going to be huge increase. But it will still be better.

They won't give you more top end speed - but they can allow you run faster under certain sea states and still be comfortable. They also allow you run a slower "on plane" speeds.

Once you have tabs, and get used to them, you'll never want a boat without them.

Tabs will help with list and pitch. You can control them with switches and/or install an optional "auto tab control" that will constantly work to keep the boat at the attitude you set it to. I highly suggest learning how to use them manually, though, you have a better idea of what they're doing and also just in case the ATC takes a dump. Plus there are times where you may want to override the ATC.
 

enfish

Well-Known Member
Joined
Oct 17, 2006
Messages
433
Reaction score
68
Points
28
Location
San Marcos, CA
Model
Adventure
Speed and fuel savings... that's tough to answer because it depends on conditions. What trim tabs allow you to do is stay on plane at lower speeds and level out the boat due to conditions, whether that be where passengers are sitting while underway or wind and chop direction. Things like getting up on plane faster are pretty negligible for overall fuel economy.

In some cases, the trim tabs will slightly lower fuel economy and speed due to more drag in the water (with the trade-off being a smoother ride). In other cases they will allow you to travel at a speed that would otherwise be impossible given the water conditions, so in that case they could potentially save you a lot of fuel and give you a lot of speed.

Bottom line... trim tabs allow you to make the boat more comfortable and safer while underway, and that's pretty much the only reason to have them. I would never own a v-hull boat designed for offshore without them.
 

enfish

Well-Known Member
Joined
Oct 17, 2006
Messages
433
Reaction score
68
Points
28
Location
San Marcos, CA
Model
Adventure
Yup, trim tabs have no effect on roll (or pitch) at slow speeds. But they would have a tremendous impact on stability, ride comfort, hole shot and fuel economy at speed.

The way to solve help roll at slow speeds is with a wider-beam boat.

The way to solve roll issues at slow speeds is by installing a SeaKeeper. www.seakeeper.com :)
Don't forget paravanes, Dennis... ;-)

 

seasick

Well-Known Member
Joined
Aug 19, 2008
Messages
9,141
Reaction score
1,310
Points
113
Location
NYC
The trim tabs will help greatly dealing with uneven loads.
With regard to fuel savings and speed, I probably have a different opinion than most.
There are those who think that tabs should rarely be used except when listing needs to be corrected. This view is based on a hull that is well balanced at rest and getting on plane. This view also says that all trimming should be done using the motor trim and tabs shouldn't be used assuming no listing. I kind of agree with the theory.
Often times a hull is not balanced well especially older hulls that had 2 strokes but were repowered with 4 stokes causing the sterns to sit lower in the water. Sometimes you get a boat that has a hard time getting on plane and tabs can help lift its stern.
When deployed, trim tabs add drag. If they reduce the drag of the hull more than they add when deployed, the fuel efficiency goes up. Likewise if you use tabs to push the bow down, that probably adds more overall drag and fuel efficiency goes down. Sometimes you have no choice about where the bow needs to be

In your case when having passengers aboard, tabs can help or actually be needed to get the hull on plane. From a practical aspect, if you need tabs deployed to get the boat on plane and stay there, use as little as possible and when you are on plane reduce tabs as much as possible while still staying on plane. Remember that the motor trim affects performance and it is important it is to learn how to trim your motors for your hull and sea conditions
 
  • Like
Reactions: trapper

glacierbaze

Well-Known Member
Joined
Jul 6, 2012
Messages
2,344
Reaction score
599
Points
113
Age
75
Location
Chapel Hill and Pine Knoll Shores, NC
Model
Seafarer
10 X 12 M120 Sport tabs, unless the MIL is over 300 lbs, then you might want to go up a size ;). Something like this.

 

blindmullet

Well-Known Member
Joined
Oct 19, 2015
Messages
449
Reaction score
106
Points
43
Location
Florida
Model
Explorer
Any pro vs con between the electric actuators and hydraulic?
Yep, and each have their application. If it's a small boat with limited space electric is the way to go. Electric is MUCH more responsive. The hydraulics are usually easier to repair and probably have a longer life expectancy. I have both and like the electrics better.

If the boats stored in the water I would go hydraulic for sure.
 

DennisG01

GreatGrady Captain
Joined
Sep 1, 2013
Messages
6,817
Reaction score
1,208
Points
113
Location
Allentown, PA & Friendship, ME
Model
Offshore
Last edited:
  • Like
Reactions: enfish

DennisG01

GreatGrady Captain
Joined
Sep 1, 2013
Messages
6,817
Reaction score
1,208
Points
113
Location
Allentown, PA & Friendship, ME
Model
Offshore
Any pro vs con between the electric actuators and hydraulic?
Space is certainly a consideration - but the hydraulic unit is plenty small and you'll have room for it. But the pros/cons are pretty much what was said above. Personally, I've seen electrics fail at enough of a higher rate to prefer hydraulics... which, for the most part, go for decades without even thinking about them.

FYI, if I can add on to what Mullet said about "responsiveness"... what he means is that they "move" faster up and down. The end result on the boat is exactly the same.

As far as sizing goes... go with the largest span you can fit. Span is more important than chord. Google those terms and read up on tabs.
 

steveditt

Well-Known Member
Joined
Nov 11, 2012
Messages
148
Reaction score
23
Points
18
I was interested in the Auto also but they have issues I would be spending way to much time re calibrating them , I upgrade to the LED controls so you know exactly the position of each , had them a few years and they are simple to use .
 

DennisG01

GreatGrady Captain
Joined
Sep 1, 2013
Messages
6,817
Reaction score
1,208
Points
113
Location
Allentown, PA & Friendship, ME
Model
Offshore
I was interested in the Auto also but they have issues I would be spending way to much time re calibrating them , I upgrade to the LED controls so you know exactly the position of each , had them a few years and they are simple to use .
Which system are you talking about? Bennett's ATC has been around for decades and is pretty much fool proof. For reference, I'm speaking from experience - I've personally used it, but my shop has also installed them for quite a few customers over the years.
 

TIDE

Active Member
Joined
Jan 9, 2022
Messages
28
Reaction score
4
Points
3
Location
Chesapeake Bay, Maryland
Model
Seafarer
Space is certainly a consideration - but the hydraulic unit is plenty small and you'll have room for it. But the pros/cons are pretty much what was said above. Personally, I've seen electrics fail at enough of a higher rate to prefer hydraulics... which, for the most part, go for decades without even thinking about them.

FYI, if I can add on to what Mullet said about "responsiveness"... what he means is that they "move" faster up and down. The end result on the boat is exactly the same.

As far as sizing goes... go with the largest span you can fit. Span is more important than chord. Google those terms and read up on tabs.
I understand. Dedicated a good bit of time researching them. I need to measure the span this spring to actually see how big of a tab I can fit.
 

TIDE

Active Member
Joined
Jan 9, 2022
Messages
28
Reaction score
4
Points
3
Location
Chesapeake Bay, Maryland
Model
Seafarer
I was interested in the Auto also but they have issues I would be spending way to much time re calibrating them , I upgrade to the LED controls so you know exactly the position of each , had them a few years and they are simple to use .
I like the idea of the autos, but after reading up on them It seams like the auto function only works after you get on plane not out of the hole. It just holds your setting to what you set after it’s on plane. Maybe I’m wrong but that is how I took it. With that being said - rather save the money and go with the LED controls.
 

DennisG01

GreatGrady Captain
Joined
Sep 1, 2013
Messages
6,817
Reaction score
1,208
Points
113
Location
Allentown, PA & Friendship, ME
Model
Offshore
I like the idea of the autos, but after reading up on them It seams like the auto function only works after you get on plane not out of the hole. It just holds your setting to what you set after it’s on plane. Maybe I’m wrong but that is how I took it. With that being said - rather save the money and go with the LED controls.
I still don't know what system (there are a few) the two of you are referring to, but the Bennett ATC will work ALL the time, including helping hole shot. You set it one time and it retains that. But of course you could change it or override it.