Stabilizers: A Must for Passage-Making?

[Hippocampus]

The problem with ultralights is they must be kept ultralight to perform. Same for performance multihulls . Over weighted safety can deteriorate as well. This is the opposite of what you want as a cruiser. Every time we’ve sold a boat been amazed how much stuff (watch Carlins routine) needs to be removed. For racing captains get ridiculous. Raced a Chris White designed tri to Bermuda. Owner was even interested in eliminating weight from our sea bags.
Had occasion to watch production power cats, sailing cats and mono hulls going to weather traveling from Tortola to north south BVI. All were charter boats. The multis hobby horsed terribly. A privately owned Outremer was with them and stayed flat as we did. The power cats did the worst not having the benefit of the stabilization from sails. Think as regards ride there’s much to say for tris if going with power. Especially those with long lean central hulls and short empty amas. Not the LEENs. One needs a very long central hull to decrease risk of pitchpoling and again weight is an issue.Still the LEENs offer a great cruising interior and achieve category “A”. Tenants designs seem to allow some weight to allow a cruising lifestyle but looking at the designs would seem to be prone to issues going to weather in a seaway. Have no experience on power cats beyond small center consoles for fishing. Would be quite interested in others experience.

 

[Marco Flamingo]

So what were your measurements?

The largest roll I saw was 5.1 degrees (not enough to knock over a pop can), but I was preparing myself for worse while watching the approaching wakes. It was the setup for throwing stuff on the floor. But the ART stifled it fairly effectively. It would start out as the old port/starboard/port roll building. That's when you look out and see that there are 3-4 more big waves coming. While an ART probably does have a "tuned" sweet spot, it tends to dampen from the beginning, and then (for my experiment) when a 5 degree roll comes, the roll is stalled a little, the roll back is only a 4 instead of building to 7 degree, then a 3, then the hull doesn't get back in sync while the rest of the wake passes, sometimes with just a final slap on the side of the hull.

I really, really wish my free inclinometer app had a recording/time function. My decibel and vibration apps both have that. For wakes, what it feels like is that the ART dampens the roll by modifying the roll period based on degree of inclination. A normal harmonic wave pattern can't do its mischief because the hull no longer plays a "single tune." At least that's what it feels like. There were times when it felt like "What? That's it? The whole wave train hasn't even passed yet."

The most pitch I saw was 2 degrees throughout the day, but I wasn't concentrating on that. In fact, I was trying to lay sideways to the various wakes.

 

[Mako]

Marco it would be good to take your measurements, then drain the bladder and take measurements again. great comparison on actual performance

 

[Marco Flamingo]

Marco it would be good to take your measurements, then drain the bladder and take measurements again. great comparison on actual performance

For anyone still following and interested in numbers rather than feelings, I did find an inexpensive recording inclinometer. $50 instead of a free app. It might give too many numbers. It is magnetic, so has to be mounted properly. It seems to be Android and PC. Biggest complaint seems to be that the "instructions" are standard Chinglish. But, for purposes of examining roll/pitch/yaw/degree/acceleration/period/decay, etc., it would (could?) provide actual data.

 

[Xlantic]

Maybe this app?

ClinoScope

toon|ClinoScope Support - toon,llc.

Have not tried it but it seems to record inclination over time.

 

[Marco Flamingo]

Maybe this app?

ClinoScope

toon|ClinoScope Support - toon,llc.

Have not tried it but it seems to record inclination over time.

That's the gadget, but for an iphone, which I don't have. If one looks at the "Time" section of the web page, it records the roll (of something) with the roll periods and magnitude. The roll that it shows stays the same magnitude for awhile but the period gets shorter. That would be a very nasty (and not likely) condition for a boat, but it does show that one would then have actual data to compare.

 

[Hippocampus]

What struck me as interesting about the SeaKeeper is the roll jus doesn’t seem to occur at all right from the beginning. No apparent latency to the effect. My limited experience is even active fins have a fraction of a second or so to act. Have yet experienced a strong beam wind to see if a sustained list occurs as some suggest. However been in gusty winds not a constant 20kts. However in 10-20kt seems not to. Suspect that varies with the boat.

 

[mvweebles]

What struck me as interesting about the SeaKeeper is the roll jus doesn’t seem to occur at all right from the beginning. No apparent latency to the effect. My limited experience is even active fins have a fraction of a second or so to act. Have yet experienced a strong beam wind to see if a sustained list occurs as some suggest. However been in gusty winds not a constant 20kts. However in 10-20kt seems not to. Suspect that varies with the boat.

Good point. Fins can sometimes have a short lag, sort of similar go a NYC subway that slightly jostles side-to-side.

I look forward to hitching a ride on a gyro-equipped boat someday. It's a cool system.

Peter

 

[Steve1.0]

What struck me as interesting about the SeaKeeper is the roll jus doesn’t seem to occur at all right from the beginning. No apparent latency to the effect. My limited experience is even active fins have a fraction of a second or so to act. Have yet experienced a strong beam wind to see if a sustained list occurs as some suggest. However been in gusty winds not a constant 20kts. However in 10-20kt seems not to. Suspect that varies with the boat.

I've run roughly a dozen boats with Seakeepers and their ability to keep a boat FLAT (roll wise) is impressive.

I recently did a day captain job for the new owner of a Sabre 58 (very rolly boats) equipped with one as well as ZipWake trim system. We made the loop out Palm Beach inlet and back in thru Jupiter with a 3-4' beam chop/swell.

The guests all had bubbly in champagne flutes sitting on tables, and not a drop was spilled.

The Seakeepers are very impressive, and heavy. This one takes 40+minutes to spin up.
On the other hand, during a delivery from Savannah to Stuart in a new 53 Riviera fly bridge, I had a different experience. We left St Augustine on the second day with 6-9' quartering seas from the NE. The seakeeper aboard overheated after about an hour, and went to stand by. The rolling became crazy. I was hanging onto the helm and console to keep from being tossed about bridge. Needless to say I called it, and came in Ponce inlet, finishing the trip in the ICW.



Overall, my limited experience with the SK's is very positive.


P.S. No affiliation with SeaKeeper. Just another delivery mule.

 

[cardude01]

That's one reason aft pilothouses are typically more comfortable than forward. It's a better placement and makes pitching motion much more tolerable. Of course, you're typically still up high, so rolling motion is rather noticeable.

The Pilothouse is pretty far aft on my boat, and the helm is just past amidships. When it gets really rough on crossings I will sit all the way aft in the pilothouse (with the steering on autopilot), and if I’m feeling sick outside in the cockpit for a few minutes is even better.

 

[libertas]

To stabilize or not

This has been a very interesting thread for me to read. New to the forum but an experienced boater/sailor, now moving to the dark side. Looking at both Defever 49 CPMY and Grand Banks 46 Classic. I know these boats are somewhat apples and oranges, one being a planning hull and the other a more displacement hull. one with twin 135's as standard and the other with 375's to 435's. I always thought that the slower you are going to go the more you will want stabilizers. There do not seem to be many GB 36 made with active fins, many more of the Defever's are.
Anyone seen a Seakeeper added to a Defever 49?? Aside from the space requirements sounds like it would work well. Maintenance??To
To the GB owners out there, how do the hard chines work out at anchor. Do they tend to be more suseptable to roll than the soft chine round bilge, KK, or Defever ect.??


Libertas
Future Trawler Owner
Past Tayana 52 owner

 

[mvweebles]

This has been a very interesting thread for me to read. New to the forum but an experienced boater/sailor, now moving to the dark side. Looking at both Defever 49 CPMY and Grand Banks 46 Classic. I know these boats are somewhat apples and oranges, one being a planning hull and the other a more displacement hull. one with twin 135's as standard and the other with 375's to 435's. I always thought that the slower you are going to go the more you will want stabilizers. There do not seem to be many GB 36 made with active fins, many more of the Defever's are.

Anyone seen a Seakeeper added to a Defever 49?? Aside from the space requirements sounds like it would work well. Maintenance??To

To the GB owners out there, how do the hard chines work out at anchor. Do they tend to be more suseptable to roll than the soft chine round bilge, KK, or Defever ect.??





Libertas

Future Trawler Owner

Past Tayana 52 owner

At anchor, very few boats have stabilization. Good news is relatively affordable to add. Forespar makes ourrigger poles. Ballpark guess is $5k. Not all cruising grounds are rolly so maybe that explains why few have flopper stoppers.

The GB46 and DF49 are more similar than not. Some folks like a pilothouse and small aft deck. Some like a social inside helm and flybridge. Both have a lot of teak. Both could take you from Alaska to Maine in relative comfort and similar costs. Both a couple cabins plus some room for a couple additional guests. PH layout tends to be a bit chopped up. Trunk cabin layout tends go not have great outside space except for flybdige. I personally like sedans but they probably have the least amount of accommodation space of all layouts.

I'm big on having some form of active stabilization when underway. If you're at the outset or your search, I'm sure you have a list of nice-to-have vs must-have. Stabilization is on my must-have list - its expensive and difficult to add. Better to let a previous owner take the hit on that one.

Good luck.

Peter

 

[balder8]

I learnt a lot from this forum about paravanes and how design this system. I have hydraulic fins running well but for long passage 4 to 5 nights and days several hundred miles from shore, I like idea of a simple mechanical back up. I have know finished more or less my horizontal foldaway paravanes project. To be honest, I am more concerned by all questions I have to answer in marinas or anchorages from other yachties and oftenly sailors who ask me : what bloody hell is the very strange rig you have on your boat? Are you an ex fisherman? is your trawler a conversion boat? and sometimes " gosh, this is so uggly.... ". Even the man who welded it for me said in spanish to his worker: it is the first time I am transforming a nice yacht in a fishing boat! Que du bonheur.
Filling a little bit guilty, I reduce a bit the lenght of the pole ( twenty centimenters..." Stop joking, I must now try seriously the system easy to deploy, the two arms are rotating on bearings and maintyened at a 90 deg by two dynnema 12mm. The fishes are stored on fore deck.
I have not been able to calculate the weight and dynamic pressure on the arms and I wonder if I should not install these poles vertically like most of you are doing in US or Canada, instead of New Zealand or Australia where you see more rotating poles. I wanted to avoid too much weight in the height and have a lot of space on roof top to welcome the poles. As well, I thought it was more secure to push and pull the poles than lift them and let them underway suspended by ropes. I read also on trawlerforum that most of maths coming from excellent book written by Robert Beebe should be exagerated and even with a 25 kg fish, it is not so heavy for a steel boat like mine. My poles are 60mm - 23" galva steel diameter, lenght 18'. The two stand pipes are rotating on each side of the beefy structure in X bolded on the roof top ( on a wall) .Material is also 23" galva pipe with inside a stainless steel bar.nb: the smaller vertical poles in stainless steel are more "lighter" paravanes I use only with flopper stopper in more or less quite anchorage or to use with fishing lines.

 

[KnotYet]

Your vessel is still quite lovely to my eyes, B8.
My few bits to add: for those not versed in the metric system, 60mm =~ 2.36".

I would employ only the bottom pipe run, using perhaps 80-100mm (4") pipe and
could be better in aluminum and of sufficient wall thickness for the compression load.
If you prefer the industrial look the bottom pipe could be square or rectangular tube.

The top pipe is only ever in tension so is best replaced with wire rope, rod or chain.
The truss bars would not be needed. The higher up the top pick is the better but it
would work OK as you have it placed and the pipe could swivel and stow likewise.

The overall effect would look perhaps a bit less workboat-like with the same results.
Another approach would be to use the salvaged spars and rigging from two 20 or so
foot long sailboats. That would retain the 'yachty' hardware look and work nicely.

 

[RT Firefly]

Greetings,
M. b. Ignore the critics. YOUR boat and if it works for you, there is really nothing to criticize. As to the nay-sayers...

 

[KnotYet]

Greetings,
M. b. Ignore the critics. YOUR boat and if it works for you, there is really nothing to criticize. As to the nay-sayers...

View attachment 156828

RT, see my opening line! Not criticisms, merely my observations of how things work.
I'm just a retired engineer with too much time and too few current projects.

 

[balder8]

@KnotYet, thank you very much indeed for your experienced advice. I need to translate it in french to be sure to understand it well ,technically speaking!The truth is that with our trawlers, we all are looking or are in need of less rolling and more stabilization. Sometimes I am missing sailing yachts but I do remember that if you like an efficient sailing yacht, most of the time, you will walk "on the walls" or go without sails up , so motoring. If you are travelling in Med ( no wind or too much wind most of the time) you will see a majority of sailing yachts under engine and by the way rolling like pigs. Considering the initial debate, here in Europe, looking for stability is something new as most of yachtmen switching or making the choice for powerboats or motorboats were more keen to opt for fast planning boats like princess, azimuth, jeanneau etc , less concerned by comfort required at 7 or 8 knots or slow mode.Beneteau introduced the " trawler" attitude when they decided to copy a Grand Banks with a semiplanning hull, what the founder of Beneteau have done very well 100 years ago with the small "peche promenade" range of boats built at the very beginning of this boatyard. The trawler marketing has been very efficient here and also in USA with the swift trawler success: means less fuel burning, more long range possibility, (also cheaper price, mass production)
When I read and read again the Robert Beebe s book, I understand how modern was this Captain.

 

[BelleAurore]

Do you want your first big boat experience to be enjoyable or an ordeal when you leave the dock? While many go without stabilizers, most would choose them. Trust me - there will be more than enough opportunity for 'an ordeal' from other factors while cruising, so why not choose crew comfort?

The difference we've seen while turning stabilizers on/off in even light seas has been remarkable. Our older technology NAIADs are still supported with spare parts & service techs. Some maintenance required but well worth the trouble IMHO.
We looked at a 53' Defever with the Gyro Gale system and that looked interesting. Owner raved about it. Had to give up a large locker space for the compressor though. It also needed its own cooling fan in the space.


My vote is for a stabilized version of whichever boat you choose.

We have Gyro Gale. Our system has 4 fins and instead of a compressor that needs a locker we have two gear driven air compressors mounted on the back of each of our engines. Air feeds to a dryer then to a holding tank and on to a regulator for distribution. My sea legs are a bit better than the admirals but we both benefit from a steady boat whether from a large impolite fishing boat passing in a channel or a beam sea.

 

[RT Firefly]

Greetings,
Mr. KY. My comment was NOT meant for you at all! I was referring to the people Mr. b mentioned in his post (#253). "Other yachties, sailors and the welder" who said his boat was "uggly". I have yet to disagree with any of your 1,539 posts........so far.

 

[balder8]

Greetings,
Mr. KY. My comment was NOT meant for you at all! I was referring to the people Mr. b mentioned in his post (#253). "Other yachties, sailors and the welder" who said his boat was "uggly". I have yet to disagree with any of your 1,539 posts........so far.

View attachment 156829

Hello RT Firefly, thanks for your add. I appreciate a lot the courtesy and friendly atmosphere of this forum, not so frequent on french or european forums where everybody mix sometimes insults or non constructive political consideration!With a trawler you are sometimes considered as nothing: not efficient elegant and brillant for italian fast planning yachts owners , and like nasty polluting guy for supposed real sailors...

 

[Hippocampus]

Have wondered how much stabilization fins provide when fixed in a neutral position. Fin failure seems to be more likely from power failure or hydraulic failure. Unlike fish failure of a fin, even its destruction does not present a risk to the vessel. Canadian government pointed out this fish associated risk rather forcefully.

One would think much like rolling chocks fins in neutral position especially at speed would provide some stabilization. Question I have is how much? I note my gyro even when not fully spinned up and therefore fixed so not allowed to provide precession does seem to provide some stabilization. Would think it’s the same for fins.

Would note engine size for full displacement sailboat hulls is much smaller than similarly sized SD powerboats. My Outbound 46 did just fine with a 90hp engine whereas my NT42 has 450hp. I do run the NT above displacement speeds with some regularity whereas obviously that never occurred under power with the sailboats I’ve owned. So continue to think recreation sail is less polluting than power. Perhaps that’s not true for blue water FD powerboat hulls but those are a small fraction of powerboats. At displacement speeds a SD or planing hull is less efficient than a FD hull.

 

[Mambo42]

Have wondered how much stabilization fins provide when fixed in a neutral position. Fin failure seems to be more likely from power failure or hydraulic failure. Unlike fish failure of a fin, even its destruction does not present a risk to the vessel. Canadian government pointed out this fish associated risk rather forcefully.

One would think much like rolling chocks fins in neutral position especially at speed would provide some stabilization. Question I have is how much? I note my gyro even when not fully spinned up and therefore fixed so not allowed to provide precession does seem to provide some stabilization. Would think it’s the same for fins.

Would note engine size for full displacement sailboat hulls is much smaller than similarly sized SD powerboats. My Outbound 46 did just fine with a 90hp engine whereas my NT42 has 450hp. I do run the NT above displacement speeds with some regularity whereas obviously that never occurred under power with the sailboats I’ve owned. So continue to think recreation sail is less polluting than power. Perhaps that’s not true for blue water FD powerboat hulls but those are a small fraction of powerboats. At displacement speeds a SD or planing hull is less efficient than a FD hull.

Since I have the experience with bilge boards, without bilge boards and with stabilizing fins on my boat I can tell you my experience.
My boat, a Defever 49, had bilge boards when I bought it, but we were rocking and rolling violently.........even in port. All boats were lying calm in the water and we were thrown around from one side of the boat to another. Out at sea those bilge boards only stopped the roll a little bit if we hit a wake of another boat.

So I decided to find stabilization and that became the electric fins by CMC. However, the bilge boards had to be taken off in order to be able to install them. In port that did not really make a difference, boat was still rolling violently.
After the fins were installed we were not allowed to use them until they were commissioned, so we were lying in the marina and spent some time on anchor in a bay close to the marina. Already then we could notice that the fins, in centralized position, had a positive influence on the rolling behavior of the boat. We were lying much steadier in the water, you could feel the fins resisting the roll movement.

After the commissioning we now use the fins while underway, on anchor and even in port. As a result our boat does not roll anymore and that was our goal.
Recently we were in Venice and there we slowed down to less than 4 kts SOG due to strong currents, in which case the fins automatically centralize themselves and we could feel a rolling motion starting, however it was more like a jerking motion, not fluent. I guess that jerky motion is due to the fins which stick out quite a bit below the boat (not below the keel, but below the hull). As soon as I put the fins in the slow speed mode it was over again, but at least we encountered a bit of rolling motion.

 

[ksanders]

Have wondered how much stabilization fins provide when fixed in a neutral position. Fin failure seems to be more likely from power failure or hydraulic failure. Unlike fish failure of a fin, even its destruction does not present a risk to the vessel. Canadian government pointed out this fish associated risk rather forcefully.

One would think much like rolling chocks fins in neutral position especially at speed would provide some stabilization. Question I have is how much? I note my gyro even when not fully spinned up and therefore fixed so not allowed to provide precession does seem to provide some stabilization. Would think it’s the same for fins.

Would note engine size for full displacement sailboat hulls is much smaller than similarly sized SD powerboats. My Outbound 46 did just fine with a 90hp engine whereas my NT42 has 450hp. I do run the NT above displacement speeds with some regularity whereas obviously that never occurred under power with the sailboats I’ve owned. So continue to think recreation sail is less polluting than power. Perhaps that’s not true for blue water FD powerboat hulls but those are a small fraction of powerboats. At displacement speeds a SD or planing hull is less efficient than a FD hull.

I do not know about fin stabilizers, but I've got a year of cruising with large rolling chocks, and the change in roll is nothing short of dramatic.

 

[tiltrider1]

The difference between my fins being active and locked is so dramatic it is hard for me to believe they do much in the locked position. If they do provide stabilization while in the locked mode I can’t imagine how bad a non stabilized version of my boat would be.

 

[Fish53]

Stabilizers do nothing to increase the seaworthiness of a vessel beyond adding to the endurance of the crew. At the same time they add complexity and in most cases additional drag. I was an offshore commercial fisherman for fifty years so I suppose I tolerate vessel motions better than some.

 

[Mambo42]

Stabilizers do nothing to increase the seaworthiness of a vessel beyond adding to the endurance of the crew. At the same time they add complexity and in most cases additional drag. I was an offshore commercial fisherman for fifty years so I suppose I tolerate vessel motions better than some.

Indeed they don't add to the seaworthiness, but there is a bit of a difference between a fishing vessel and a pleasure craft. When I look at a fishing vessel of 50' it usually has a beam of 20 - 25', it is made of steel, has a very low COG and is therefore much more stable. On top of that, a fishing vessel is not a pleasure craft, meaning you don't go out to sea for fun, it is for work.
The average pleasure craft is (for most people) a means of transportation, it is what they live on and it is not meant to be a working vessel. The majority is made of GRP, beam is more narrow and is not immediately made to go into 10 BFT on a regular basis.
Being out at sea is nice, you can get to places, it has a different effect on everyone, but if there is no need to be uncomfortable.......then why should it be uncomfortable ? Stabilizers can make life onboard comfortable and we prefer that over being thrown around in the boat.
I don't get seasick, can go in very heavy conditions, but continuously having to grab to absolutely everything to keep your balance just wears you out. And that is not why we live on a boat.

 

[Hippocampus]

Have done a fair amount of blue water passages. Personally know of many boats that were abandoned, required outside assistance or presumed sunk due to crew fatigue. Crew fatigue is a safety issue. Many people going from coastal cruising to blue water voyaging have never experienced sustained bad weather. Not survival weather but just more than >24h of bad weather. Unless it’s a mixed crew (majority old salts) it can be scary to the degree anxiety interferes with performance, sleep and continuation of ADLs (activities of daily living such as eating, drinking and hygiene). The decreased performance affects safety.
Although my experience has been on sail but I know there’s a huge difference in quality of life being on a sea kindly hull v a rough ride. Simple things like moving around, cooking, getting something out of a locker, changing a racor or doing other things becomes a frustrating hard thing. And you pickup more bruises from bumping into things.
So I firmly believe what was called “comfort quotient ” in the past is important for safety. Although stabilization has no effect on AVS think it does improve safety.

 

[chanprr]

I agree with Mambo42 in that boating can be much more pleasurable and comfortable with stabilizers. Having ploughed through rough water on several legs on our last cruise up to SE Alaska, I was convinced that adding stabilizers would make crossings more pleasurable, and we wouldn't have to wait if the weather was a bit iffy. The only question was, active fins or rotors. After much consideration, discussion, including on the water demos, I chose the Magnus Master twin rotors for my Helmsman 46. The H46 should be on the water soon and we will cruise over the winter months in the PNW, and I will post comments as time goes by.

 

[Hippocampus]

Have read multiple threads about what’s needed for passage making. In a brutally pragmatic view I find what’s too often overlooked is crew.
Small boat passage making has a quandry. Most plan food and water on the basis of enough food for the length of the transit plus a safety margin of a third more. And then storm stores on top. You also plan for enough bottled water with the same parameters in case the watermaker fails. So each crew means a lot more storage. Then you need to consider sleep. At a minimum that means three but most skippers like four in case one goes down or is inadequate. Losing a crew is a big deal. Having a crew partially disabled is a big deal as well. Even a minor injury from a bump or poor sleep is enough. On a big boat all this is less of concern. Having more crew and space for no hot bunking makes these concerns less of an issue. So doing everything you can to improve comfort is imperative. Yes stabilization helps.

 

[mvweebles]

Stabilizers do nothing to increase the seaworthiness of a vessel beyond adding to the endurance of the crew. At the same time they add complexity and in most cases additional drag. I was an offshore commercial fisherman for fifty years so I suppose I tolerate vessel motions better than some.

"Adding to the endurance of the crew" is not inconsequential - as Hippocampus points out, there are significant safety benefits to a comfortable and stable platform. But beyond that, for most folks, boating is a discretionary past time - recreation. Arguably, boats in the class of TrawlerForum members are always a jumble of complex additives to achieve benefits of comfort or convenience: a compromise.

A couple observations:

First, owners with stabilized boats love them and would never go back to un-stabilized boats.​

​

Second, I've met a few retired commercial mariners. When they bought a boat for recreational use, they did NOT buy a commercial boat. They bought something intended for recreational use.​

Peter