Trawler Rocking, Rolling and Stability

[Don L]

Something like this then? These are for flopper stoppers only though.

Do they work? Be honest and not just because you spent the money.

 

[rslifkin]

Something like this then? These are for flopper stoppers only though.

Yeah, something exactly like that. But maybe in a beefed up form (and with the ability to angle upward while in use) to allow use with paravanes.

 

[Datenight]

Something like this then? These are for flopper stoppers only though.

I am looking for something like that. Are they commercially available or did you have them made?

If custom, how long are the poles and what type of "fish" do you use?

Thanks,

Rob

 

[Todd R]

https://www.trawlerforum.com/forums/s68/flopper-stoppers-sale-66977.html

These are in Classified

 

[long-cours.62]

Any idea of the cost

Any idea of the cost to ad this type of equipment ok it is made for use "on the way" but it must also work at anchor .

 

[Fletcher500]

Any idea of the cost to ad this type of equipment ok it is made for use "on the way" but it must also work at anchor .

Hmm.

 

[Airstream345]

We installed the Magma system last season and use all the time in rolly or exposed anchorages. It works surprisingly well and stows into a medium size dock box on deck. I was pleased given we're at 33 tons (more when full) as it really slows the roll down signficantly.

A friend has paravanes on a KK42 which they use underway and then switches the fish out for floppers on anchor. He swears by this system and given he crosses the Columbia River Bar each season I trust his perspective.

We draw 5.5' and have 10% ballast in the keel. We also have a ketch rig that we use for steadying (more than most trawlers but far less than the same size motorsailor) which works well in beam conditions. Long term plan is to add paravanes.

 

[Bmarler]

We installed the Magma system last season and use all the time in rolly or exposed anchorages. It works surprisingly well and stows into a medium size dock box on deck. I was pleased given we're at 33 tons (more when full) as it really slows the roll down signficantly.

A friend has paravanes on a KK42 which they use underway and then switches the fish out for floppers on anchor. He swears by this system and given he crosses the Columbia River Bar each season I trust his perspective.

We draw 5.5' and have 10% ballast in the keel. We also have a ketch rig that we use for steadying (more than most trawlers but far less than the same size motorsailor) which works well in beam conditions. Long term plan is to add paravanes.

are you deploying on both sides or just one?

 

[Airstream345]

are you deploying on both sides or just one?

sometimes one, but floppers on both sides seems to give us the best roll attenuation.

 

[Capt Ray]

My high school and college days were spent aboard a 31 ft Seafarer sailboat with a full keel 6 ft draft. I would usually be heading out in the afternoons when the wind was picking up. Most of my classmates who lobstered for a living would be heading IN. "Early to be early to rise makes a many healthy wealthy and wise." as Ben Franklin wrote.

Years later, as I got older and my wife and I got into a power boat for our cruising adventures, it did not take long for me to realize there is a fundamental difference between cruising on a sailboat v. a power boat.

Under sail, we put our miles on in the afternoon when there was wind, and white caps, and we'd try to time it to be pulling into port with the setting sun in our eyes!

In a power boat, we found it best to be up with the sunrise, and put our miles on before noon or 1:00pm ... before the wind picked up.

It is simply the nature of the beast. There are fundamental differences between the two. The "Go / NoGo" criteria and choice becomes more important with a power boat. So establish your Go NoGo Criteria based on your boat and your crew's comfort. Make pleasure boating live up to its name!

There are wing stabilizers and gyrostabilizers you can inve$t in. Cha Ching.
But few boats can accommodate them that were not designed to handle the stresses on the hull that they present. Though the persons who have them LOVE them. There are also trim tab stabilizers that are dynamic to accomplish the same thing.

As you morph from sail to power, you are fundamentally changing the platform ... so be ready for making adjustments!

Shellerina [.com]

 

[Simi 60]

Any idea of the cost to ad this type of equipment ok it is made for use "on the way" but it must also work at anchor .

Here in Oz they cost I would hazard a guess at $30,000 for a 60fter
Still way cheaper than actives or gyro
And they do work well both underway and at anchor going on observations of boats that have had them near us.

 

[Insequent]

Do they work? Be honest and not just because you spent the money.

LOL!
Have a read of an earlier discussion. I can now use open roadstead anchorages that previously needed ideal conditions.

https://www.trawlerforum.com/forums/s3/flopper-stoppers-59139.html

 

[Insequent]

Yeah, something exactly like that. But maybe in a beefed up form (and with the ability to angle upward while in use) to allow use with paravanes.

They do angle upward. If I am only moving a few miles to another anchorage I simply retrieve the "gullwings" and then secure the pole in a vertical position

 

[mvweebles]

Do they work? Be honest and not just because you spent the money.

Yes they work. I had them before - old school 4" diameter spinnaker poles that were heavy and ungainly. So during my refit, I replaced them with lighter 3" poles with much easier to use fittings at a total cost of around $3k. Once set, the old and new ones are functionally equivalent. So yea, in my opinion they worked well enough to justify upgrading them. They really attenuate the oscillation.

Peter

 

[Insequent]

I am looking for something like that. Are they commercially available or did you have them made?

If custom, how long are the poles and what type of "fish" do you use?

Thanks,

Rob

I had them fabricated. The flopper stoppers are the same as the Magma Rock'n roll units.

https://www.whitworths.com.au/magma-the-rock-n-roll-boat-stabilizer

They were basically unavailable world-wide for more than 6 months. However, the patent has long expired so I had a pair made for $300. Better than the advertised price, each!

You could use the Magma poles, but others might be better. Some guidance was to have the poles half your beam, so mine are 8' long. If doing again I would likely go a bit longer. Here is a close up pic of the "gooseneck type joint that allows both horizontal and vertical movement.

 

[Simi 60]

We went this style with our arms
And like Brian, did the Magma on steroids version of flopper stopper done in 3mm plate vs sheet metal

Whilst not a 100% fix they make the untenable anchorage good enough.
Money well spent for us.

 

[Mambo42]

I have a Defever 49 and she does like to rock and roll on anchor or even in the marina when it is windy. So we went searching for the right stabilizers and yes, they had to work underway and on anchor.
Problem of course is that a trawler travels at low speed, which makes the stabilizers less effective.
Peter wrote

At-anchor stabilization. There are two choices. Seakeeper gyro which requires the generator be running (and being a fairly new option, is only found on newer, more expensive boats likely out of your budget). Or "Flopper Stoppers." These are outrigger poles that look like Paravanes but are much less robust because they are only used at anchor, not underway. Paravane rig can be used as flopper stoppers, but not vice versa. Forespar makes a nifty flopper-stopper setup - my boat had spinnaker poles originally that I replaced with the Forespar poles. I have them on both sides of my boat.

And I have to agree with the gyro's, they are no option. They guzzle electricity, take up an enormous amount of space and the bearings need to be changed basically every 3000 - 6000 hours.
Flopper stoppers would be nice, but in order to install that I basically have to reconfigure the whole boat, not really an option.

So, in comes option nr 3 and that is electrical fins that can rotate 360 degrees, which work both underway and on anchor. After speaking with almost all suppliers of stabilizers I finally decided on CMC Stabilizers. Their system requires the least amount of additional equipment on board, no hydraulics and if you would hit the fins on something (rocks, ground etc) the fins will just shear off and can be replaced easily. There is no metal shaft sticking through them.

Officially the Stab 20 would fit our boat, but after seeing an episode of MV Oloh on Youtube and after talking to them (thanks guys for the kind advice) I decided to go for one size larger, the Stab 25.
They will be installed this summer and we will put them immediately to the test. That period of the year is the time of the Meltemi winds, which can cause very rough seas in a matter of minutes (highly unpredictable).
Not that we plan to go out in that weather, but if we do get caught we should be fine. Normally we won't go out in weather that you will find in Deadliest Catch, so we should be fine. Also spoke with some users of the Stab series and they love the system.

So, am looking forward to see them installed, space has been made available and I will document the whole installation process.

 

[Datenight]

I had them fabricated. The flopper stoppers are the same as the Magma Rock'n roll units.

https://www.whitworths.com.au/magma-the-rock-n-roll-boat-stabilizer

They were basically unavailable world-wide for more than 6 months. However, the patent has long expired so I had a pair made for $300. Better than the advertised price, each!

You could use the Magma poles, but others might be better. Some guidance was to have the poles half your beam, so mine are 8' long. If doing again I would likely go a bit longer. Here is a close up pic of the "gooseneck type joint that allows both horizontal and vertical movement.

Thanks Brian, The plates are easy to get now. I really like the idea of the poles folding alongside. The photos are great!

Thanks again,

Rob

 

[Roy Ferguson]

As I look at trawlers they all seem to have 3.5-4' draft (a plus to someone who has been cruising around on 6'4" draft). I have to wonder about the rocking, rolling and stability of these. They are low draft and high windage with nothing really to stabilize it. Let me tell some observations so you know how I view it (all I can currently base it on whether right/wrong):

My first trip across to Bahamas we were sailing and in sight of a trawler in front of us most of the trip. We watched this boat for hours just rolling back and forth in what we considered pretty mild open water seas. We later asked the guy how his crossing was and he said "It SUCKED"

Last week at an anchorage I met up with some ex-sailors on a 44' DeFever that they had "fitted" out for "comfort". It had a 6' draft and stabilizers (the ones on poles that have the plates, don't know what those are called). At anchor they rolled around just as much as us. A few days ago they were next to us in what turned out to be a terrible anchorage for rolling due to the surge. They were rolling just a much as all the sailboats and like me were pulling up anchor a first light to get out.

So what should I look at far as type and design to reduce this issue in a trawler? It didn't seem to me that the 6' draft made any difference at anchor. Are those pole type stabilizers and trawler sails really of use?

I am sure I am asking a loaded question because far as trawler go I don't enough to ask a more specific one.

Or is this just something you have to put up with and try to plan around?

thanks

The best you can do are hydrolic stabilizers, steady sale can help under the right conditions.. avoid a soft chine. Roy Ferguson

 

[rpackard]

On my Willard 40 I used paravane poles underway in rough beam seas and, if the anchorage was rolling, I switched them to flopper stoppers. If using flopper stoppers you need to have something elastic in the down line or else the boat gives a big jerk when the vanes open.

 

[Datenight]

Hi Brian,

Three more questions on your flopper stoppers.

1. Do you mind if I copy your hinge assembly?

2. Could you supply the wall thickness and diameter of the poles?

3. Do you have a photo of how the lines attach to the end of the poles?

Thanks,

Rob

 

[mvweebles]

Hi Brian,

Three more questions on your flopper stoppers.

1. Do you mind if I copy your hinge assembly?

2. Could you supply the wall thickness and diameter of the poles?

3. Do you have a photo of how the lines attach to the end of the poles?

Thanks,

Rob

Rob - Insequents setup is similar to the Forespar setup I used. If you don't mind the look, the H-Frame setup Simi pictures in Post 46 are much easier to deploy. Having a free end can be a bit ungainly and requires an additional topping line to triangulate the pole. I simply did not want the aesthetics but functionally, Simis setup is better. Easier/cheaper to fabricate too I'd imagine.

Peter

 

[Insequent]

Hi Brian,

Three more questions on your flopper stoppers.

1. Do you mind if I copy your hinge assembly?

2. Could you supply the wall thickness and diameter of the poles?

3. Do you have a photo of how the lines attach to the end of the poles?

Thanks,

Rob

For the hinges, go for it! They are 5mm plate. You likely can't see it from pic, but there are nylon bushing/washers on both the vertical and horizontal pivot points. Its a no-rattle design!

The poles are 50mm diameter. There are no openings to measure wall thickness - sorry.

At the end of the pole there is a sheave for 10mm line, and some holes in a 5mm end plate for snap-shackles. I fit the topping line when the poles are stowed, then raise the pole to vertical to fit the fore & aft guy lines, and feed the flopper stopper line through the sheave. So I'd suggest pole length of 50% of your beam minimum, but a couple of feet longer if you can still readily access the top of the pole when vertical to rig the other lines.

 

[Datenight]

Thank you Brian and Peter,

I have not decided which way to go yet but you have both given good advise. Simi's solution is also a simple way to go. Aesthetics are always a consideration.

The Magma Rock and Roll is also in the running but not sure if I want something on the hull. It may be difficult to mount and dismount the poles.

Thanks for the good leads and suggestions.

Rob

 

[Hippocampus]

Went from 6’6” bulbed fin to a SD hull with a SeaKeeper. Our program now is very different than it was on the Outbound. The outbound had a AVS of ~130 degrees with a very small area in the negative on the Gz. The NT does not. So you change your thinking about weather for reasons of safety not comfort. That means you are not exposed to the same kind of seas.

The problem with the Seakeeper is it’s so effective unlike the sailboat you have less tactile awareness of the sea state. Kind of like a sailing cat where you need to pay attention to small clues you are overburdened and approaching the limits of its stability. Most recreational trawlers are B not A boats. Accept that.

So since owning this boat we’ve had the SeaKeeper on for maybe 20% or less of the time. We look at what the weather is going to do daily so have at least a days notice of when to turn the thing on. It takes awhile to spin up but so far that hasn’t been an issue. It sits in the middle section of our lazerette so lost storage space hasn’t been an issue. My boat had its SeaKeeper put in 2011 and has yet to need its vacuum broken. Probably won’t need that service for another 3-5 yrs. Unlike fish don’t need to worry about if I have sufficient depth to deploy them. Unlike both fish and fins the device is inside the boat so can’t snag anything or be hit. Also doesn’t produce drag so no effects on speed.

For us and our program it’s a better choice than rolling chocks, batwings, fish or fins. Think Magnus effect might be even better but don’t know. Rather put up with using fuel to run the genset than worrying about hurting myself with fish or having things sticking out.

Due to north swell been in some really rolly anchorages in the sailboat. As said every boat sail or power has a harmonic and if direction, period and size of wave or chop is just right to be in synchrony you’ll have a lousy night. On any boat I’ve owned the usual answer is to reaanchor to a more benign spot. Admittedly sometimes it doesn’t help much or can’t be done. For sure those depending upon form stability float more on the water so behave differently. But they can be jerky or pitch more depending upon design. No boat is perfect. In crowded anchorages I’d rather use the SeaKeeper. To many idiots on PWCs and dinghies flying by not paying attention.

 

[Southern Boater]

We use two flop stoppers at anchor off our midship cleats……...

Can you describe or post a pic of your flop stops? How much improvement, say percent wise, over not deploying them?

Thanks

 

[socalrider]

Can you describe or post a pic of your flop stops? How much improvement, say percent wise, over not deploying them?

Thanks

https://www.flopstopper.com/FlopStopper/Home.html

These are the ones. It's very hard to quantify improvement unfortunately; this is SoCal, Channel Islands and Catalina - anchorages can be quite roll-y indeed.

We did a season with nothing, then a season with those orange cones - four per side. They were almost useless - no real discernible difference.

Bit the bullet and got a single flop stopper ($$). It made a significant improvement in comfort - mainly by damping out the roll much more quickly than the boat's natural motion.

We got the second and used it for two more seasons - another step up in improvement; roll damping is much faster since damping occurs on both sides.

Again, I have no measurements, but with nothing, it could be tough to walk around and make dinner. With two, you still feel some motion, but it's much more controlled. I think polls will be another big step up - I've seen some boats with just a single flop stopper and a long pole and they seem to do better than us with two off the midship cleats.

 

[redline]

I have a Defever 49 and she does like to rock and roll on anchor or even in the marina when it is windy. So we went searching for the right stabilizers and yes, they had to work underway and on anchor.
Problem of course is that a trawler travels at low speed, which makes the stabilizers less effective.
Peter wrote


And I have to agree with the gyro's, they are no option. They guzzle electricity, take up an enormous amount of space and the bearings need to be changed basically every 3000 - 6000 hours.
Flopper stoppers would be nice, but in order to install that I basically have to reconfigure the whole boat, not really an option.

So, in comes option nr 3 and that is electrical fins that can rotate 360 degrees, which work both underway and on anchor. After speaking with almost all suppliers of stabilizers I finally decided on CMC Stabilizers. Their system requires the least amount of additional equipment on board, no hydraulics and if you would hit the fins on something (rocks, ground etc) the fins will just shear off and can be replaced easily. There is no metal shaft sticking through them.

Officially the Stab 20 would fit our boat, but after seeing an episode of MV Oloh on Youtube and after talking to them (thanks guys for the kind advice) I decided to go for one size larger, the Stab 25.
They will be installed this summer and we will put them immediately to the test. That period of the year is the time of the Meltemi winds, which can cause very rough seas in a matter of minutes (highly unpredictable).
Not that we plan to go out in that weather, but if we do get caught we should be fine. Normally we won't go out in weather that you will find in Deadliest Catch, so we should be fine. Also spoke with some users of the Stab series and they love the system.

So, am looking forward to see them installed, space has been made available and I will document the whole installation process.

These look really interesting and more compact with potentially less to break then a hydraulic system. What do the costs look like if you don’t mind me asking?

 

[sjisailor]

Agreed the electric CMC look great. Various web pages list them as "starting" at $45600 USD for 12 meter vessels, e.g. https://www.nauticexpo.com/prod/cmc-marine/product-29020-556763.html I mostly see the same price regardless of model number so I assume that's for the smallest size, ~40 foot vessel.

 

[Mambo42]

These look really interesting and more compact with potentially less to break then a hydraulic system. What do the costs look like if you don’t mind me asking?

When I spoke to the owners who already had them installed they told me the price they paid in the US and that is indeed around 45.000 for the Stab 20 and 55.000 for the Stab 25.
Installation cost vary a bit. One owner installed them himself so his cost were minimal. Another one had it done and paid about 18.000, but don't know if that included the yard cost.

They are produced in Europe and strangely enough I pay the same price in euro, 55.000 for the Stab 25. The installation cost, for me, are around 14.000 euro because I get it done in Turkey and wages are much lower there than in other parts of Europe. A large part of the cost is hull strengthening and pulling wires to the pilot house and fly bridge. But since I had the boat completely rewired this winter (was necessary since cables were falling apart) I already pulled the cables they will be needing for the stabilizers.

Then again, I have to bring the boat to Turkey, while we were planning to go back to Croatia this year, so should you consider that extra cost ? On the other hand, we turn it into a one month trip, doing about 2 to 3 hours each day so we can see the islands along the way and spend time on each island we stop at.
So even though I should calculate the transit cost I really don't, we see it as a fun time, we are in no hurry, have more than enough time to get there.
Best part however is that the marina is not charging us anything for staying on the dry for 2 weeks. It is their quiet time and a few of their companies will have some work on our boat, so we only need to pay the haul in and out.

In all it is a lot of money, there is no way around it. And at the same time we are installing the lithium winston cells, but we see all of it as an investment in our pleasure and comfort. We will never recoupe the money when we sell the boat, but if we get a more comfortable ride we will enjoy the boat so much more and we do spend 7 to 8 months a year on the boat.
The admiral and our dogs do get pretty sea sick when the winds pick up at anchor and the boat starts rocking and rolling, which takes away a lot of their pleasure and we are on the water purely for pleasure. It is not nice to see everyone puking onboard and me being the only one who is servicable, long nights for everyone. So something needed to be done and to us it is worth the investment, but I can fully understand if anyone else decides otherwise. If these stabilizers would not have an 'anchor' option I would not have done it. I really wanted the double option, underway and on anchor, plus it could not use a lot of electricity and I don't want to run the generator for them. I need to be able to run them, at night, off the batteries. Since they are electric they also hardly make a sound, so you can sleep quietly. They will be installed about 50 cm after the master stateroom bulkhead, so right near our ears. Quiet was mandatory.

The lithiums are also expensive (around 12.000 euro for 1200 Ah at 24 V), but they are necessary to be able to run the stabilizers the way I want to. Good part is they will save us around 3000 euro every single month on the water (no need to run the generator at all). So in a couple of years we will have basically earned the whole investment (lithium and stabilizers) back via savings on the fuel.
Hopefully in about 10 or 20 years when we sell the boat the new owner will appreciate the approach we took, but then again...........does it really matter ? If we are happy with the result then we will call it a success. And as a (later found out) benefit.........the stabilizers will open up the whole Med to us. Parts of the Med are known to be very rough and highly uncomfortable, but hopefully with these Stabs we will be able to e.g. visit the West coast of Italy, visit Malta, go to Cyprus, cross from Italy to Ibiza and then on to Spain. Perhaps even Gibraltar to Canary islands and Azores. But that we will find out once we have them.