Stabilizing with trim flaps.

[vanderzeeh]

Hi All.
Last year during our vacation trip we docked along an Island Gipsy 32, which is pretty similar to my Integrity 32, so soon the owner from the Island Gibsy and I had a lot to discuss.


The most interesting topic we discussed was the stabilizing system he had installed and worked fine according the guy.



It was from a company called Mente-Marine and uses the normal hydraulic trim flaps to reduce the rolling of the boat.


I have never seen this system on other boats so my question is has somebody experience with this relative cheap stabilizing system.


I have doubts that my hydraulic pump is fast enough to continuesly push the flaps up and down in the same frequency as the boat rolls.


But it might be a cheap solution to change my wifes opinion to go out on the sea

 

[MurrayM]

I contacted Humphree about their hydraulic stabilizing trim tabs a few years ago and they said they weren't recommended for slow trawler speeds.

https://humphree.com/interceptors/

Maybe Mente-Marine is different, or was this set up on a 'fast trawler'?

 

[Alaskaflyer]

Not on an Island Gypsy 32, that's for sure.

 

[vanderzeeh]

Not fast no, the guy had less horsepower then I have and I can make approx 10 knots WOT, with a clean hull and downhill I did once 18 knots but a few weeks later when the Algae started growing again I was back to 10 knots WOT

 

[ScottC]

True. Tabs, interceptors and the like are best for higher speed boats. Nevertheless, I took a gamble with this a few years ago:

Zipwake | Dynamic Trim-Control System
Check their references tab for lots of real examples and photos. I'm one of them.


I don't regret it.

Interceptors.

I normally run 7 knots. But on the (rare) occasions I wanted to go 9-12 knots, I found the bow would rise to an unacceptable level. The Zipwake interceptors solved the problem for me. For 7 knots or less, they do not come on, as they would not add any benefit. As I start to go faster than 7 knots, however, they come on gradually. They also have a stabilization feature, which helps noticeably in certain sea conditions - but they are in no way a substitute for a true stabilization system. For what it's worth, my fuel consumption at higher speeds has been reduced by 5-16%.


There's a lot more detail about my ZipWake project on TF here:
https://www.trawlerforum.com/forums/s76/greenline-33-exterior-enhancement-discussions-53392.html

 

[Alaskaflyer]

Make your trim tabs automatic! » Mente Marine

Interesting, I assumed they might replace the pumps for faster action (like MurrayM suggested) but they don't, it's just a controller. Watch the video. They do say that they are designed for both planing and semi-displacement hulls. The implication - to me at least - is that they aren't hugely useful at hull speed and don't counteract rolling to any useful degree.

If I still had my cabin cruiser, I would consider the product. I am one who is constantly trimming a boat on plane.

 

[rsn48]

I have a new Merc engine with a new Bravo 2 leg. Also installed are two new electric trim tabs. I do use the leg trim and find it effective. I have yet to figure out what to use the electric trim tabs for.

Having said that, my boat at low speed suffers from wandering. Turns out this is a common problem with a single engine stern drive. One of the solutions, again note this is at slow speeds like 7 - 9 knots, is to run with the trim tabs full down to act as a damper for a wandering boat.

 

[rslifkin]

I have a new Merc engine with a new Bravo 2 leg. Also installed are two new electric trim tabs. I do use the leg trim and find it effective. I have yet to figure out what to use the electric trim tabs for.

I'd experiment with various combinations of drive and tab trim. You might find some combination gives slightly better speed (at a given throttle setting). Or you might find that other than maybe allowing the boat to climb on plane faster, your hull just doesn't have much need for the tabs.

 

[Alaskaflyer]

When I drove planing boats with trim tabs I used them for four things: 1. To assist the boat to accelerate and achieve plane sooner than it would otherwise (to "get out of the hole"), particularly when heavy; to trim the boat level in wind drift; to trim the running attitude for best performance/economy if it didn't otherwise have the type of drive (outboard, IO) that would do it; and to provide a more stabilized and thus comfortable ride in choppier seas by having the tabs force the bow down a bit (at the cost of efficiency.) Personally, I would never have a planing boat of any size without tabs.

 

[MurrayM]

To clarify...to make sure we're talking about the same thing here.

These are tabs, or blocks, that rise & fall vertically from the transom, not near horizontal plates which trail behind the transom, right?

 

[rslifkin]

To clarify...to make sure we're talking about the same thing here.

These are tabs, or blocks, that rise & fall vertically from the transom, not near horizontal plates which trail behind the transom, right?

Tabs are the horizontal plates that angle downwards. The vertical plates that extend straight down are the "interceptors" mentioned earlier in the thread.

 

[MurrayM]

Tabs are the horizontal plates that angle downwards. The vertical plates that extend straight down are the "interceptors" mentioned earlier in the thread.

Ahhh...I see the Mente-Marine system uses tabs:

Make your trim tabs automatic! » Mente Marine

 

[Alaskaflyer]

The Mente-Marine product and several others simply add artificial intelligence to your existing trim tabs, the horizontal transom-mounted devices with hydraulic or electric rams, by replacing the existing two toggle or four-button controller with a computerized device with attitude sensors included.

The Interceptor is a whole 'nuther animal which as you describe enters the water vertically, is faster acting, and they claim better efficiency. They might be fast acting enough to have some ability for active roll stabilization if fitted with a controller with sensors, but I wouldn't think they'd be very effective for that on a slow moving boat.

 

[ScottC]

I failed to mention in my earlier post that I would be VERY skeptical of a company that claimed they could make standard ”tabs” with standard hydraulic pistons move fast enough to accurately provide any amount if useful stabilization. Interceptor blades move up and down quite fast.

 

[rslifkin]

I'd expect you could make tabs move fast enough, but it'll take good actuators and a much bigger (and more power hungry) pump than most setups have. Bigger hydraulic lines as well. As an example, my large Bennett tabs (2 actuators per tab) take something like 20 seconds for full travel if you move both tabs at the same time.

 

[ScottC]

I think my interceptors take maybe 2 seconds for full travel. ( which is only a few cm)

 

[FF]

"I'd expect you could make tabs move fast enough, but it'll take good actuators and a much bigger (and more power hungry) pump than most setups have. Bigger hydraulic lines as well. As an example, my large Bennett tabs (2 actuators per tab) take something like 20 seconds for full travel if you move both tabs at the same time."

If you desire rapid movement an air powered setup should be fastest.


I know of no air system that would take immersion in sea water.

 

[Keysdisease]

Both Bennett and Lenco make auto tab control systems as add on options. In a sense as Alaskaflyers says, this just adds artificial intelligence to your trim tab system.
Also mentioned is tabs working on slower speed boats. For slower speeds, you need bigger tabs, and in some cases no amount of tab at a given slower speed is going to work on larger boats. On my olde Mainship 34 with 200HP I installed 12 x 42 tabs. The made all the difference between actually being able to plane to 15 knots or whether to wallow around and try and get on plane at 11. They did a fine job of correcting list due to load or windage, and were marginal at pitch at our usual cruise speed of 8-9 knots. Tabs can correct list and pitch if they are large enough on boats travelling as slow as the 8-10 knot range. At speeds below that they will have marginal influence as there just isn't enough water flowing over them for them to be effective.
If tabs are effective at trim control on your boat, the addition of "auto trim" will work like active stabilizers.

This is the Bennett system https://bennetttrimtabs.com/atp/

This is the Lenco system https://www.lencomarine.com/en/Products/Auto-Glide-Kits

 

[rslifkin]

"I'd expect you could make tabs move fast enough, but it'll take good actuators and a much bigger (and more power hungry) pump than most setups have. Bigger hydraulic lines as well. As an example, my large Bennett tabs (2 actuators per tab) take something like 20 seconds for full travel if you move both tabs at the same time."

If you desire rapid movement an air powered setup should be fastest.


I know of no air system that would take immersion in sea water.

Yes, a pneumatic system could be made very fast. But based on how well hydraulic fin stabilizers work, a hydraulic setup could be made "fast enough". And we know those work in water.

 

[FF]

But based on how well hydraulic fin stabilizers work, a hydraulic setup could be made "fast enough". And we know those work in water.

Trim tabs do work fine for raising or lowering the bow.

My concern is the use of tabs instead of paravanes or thru hull fins to damp the roll.

No overboard gear on deck to set , or danger with sinking from hitting an object with fins while underway.

The air pump might even be robust enough to operate a windlass or a bow thruster with no time limits.

 

[rslifkin]

But based on how well hydraulic fin stabilizers work, a hydraulic setup could be made "fast enough". And we know those work in water.

Trim tabs do work fine for raising or lowering the bow.

My concern is the use of tabs instead of paravanes or thru hull fins to damp the roll.

No overboard gear on deck to set , or danger with sinking from hitting an object with fins while underway.

The air pump might even be robust enough to operate a windlass or a bow thruster with no time limits.

Agreed, being able to make the tabs multi-purpose would be nice. And they've already proven to be a low risk for getting hit with debris. Either pneumatic cylinders or just bigger hydraulics optimized for fast movement should do the job. Just a question of which one can be made more durable.

 

[BeeJay]

Air being compressible is the issue. Pneumatics have no issue with the environment.