Stabilizers: A Must for Passage-Making?

[rslifkin]

I agree with comfort being a big factor. A few times in unexpected weather we've changed our destination or turned back for comfort reasons. Other times we've continued (sometimes with a speed adjustment). But some of the turn-backs and diversions would definitely have been avoided with stabilizers where the ride would have been more tolerable. In a few cases, the thought process has been "we could do this for an hour, but we're not doing it for 4+ hours".

The last time we turned around wouldn't have mattered though, as it was much larger than forecast head seas and still building. The ride sucked (I almost got pitched out of the helm chair a couple of times) and worse, it was slowing us down enough that at the "screw this" point we were 45 minutes into a 3 hour run and showing an estimated 3 hours to go. And as the seas got bigger we were only getting slower (and adding more power to re-gain speed only made the ride worse). After the turn-back we had a pretty comfy ride downwind, but stabilizers to take the bit of roll away while we corkscrewed a bit downwind would have made it a great ride rather than just a decent one.

Unfortunately, there's not really a low cost stabilization solution. So as desirable as they are, adding them to existing boats will always be a questionable proposition.

 

[Fish53]

"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

My intention wasn’t to say that stabilizing was useless or dumb but to simply add a little breadth to the conversation. I don’t happen to feel that the benefits of stabilizers outweigh the disadvantages to me personally. I’ve been on a boat when stabilizers failed and endangered the vessel in rough seas and having a stabilizer boom stick into the water or hang up on debris or lobster pots isn’t much fun either. All I wanted to point out is stabilization isn’t all benefit with no drawback.

 

[rslifkin]

My intention wasn’t to say that stabilizing was useless or dumb but to simply add a little breadth to the conversation. I don’t happen to feel that the benefits of stabilizers outweigh the disadvantages to me personally. I’ve been on a boat when stabilizers failed and endangered the vessel in rough seas and having a stabilizer boom stick into the water or hang up on debris or lobster pots isn’t much fun either. All I wanted to point out is stabilization isn’t all benefit with no drawback.

Paravanes in particular do have some risks due to the amount and size of hardware involved. Something like fins is a lower risk in my mind, as in most cases, a failure just means no stabilization but not collateral damage.

And of course, how much stabilizers are needed will depend on the boat in question. Different boats will ride differently and have a different threshold where the ride becomes miserable for the crew. My boat for example tends to have a fairly lively ride, so you reach the point where it's miserable to be on board long before the boat is struggling with the conditions.

 

[DDW]

A comparison between fins (inactive) and rolling chocks is meaningless without a full description of the rolling chocks. Fins are fairly generic in their size and location, rolling chocks on the other hand vary from tiny little strakes a few feet long to a few feet deep and nearly full length. Inactive fins are like short deep rolling chocks. On a centerboard sailboat, you can play with this to some degree, raising or lowering the board. Or with retractable fins.

I've not seen it done, but there is merit to the idea of a deep centerboard in a trawler. It would be at least as effective and probably more effective than batwings, without being an eyesore, would retract into the keel without sacrifice of space, and could be made to kick up when it struck something. Requires no power and minimum attention, though they do require maintenance when hauling (hard to antifoul the case).

 

[Hippocampus]

Have thought about this as well. Most centerboards are NASA foils so generate lift as well. On power would mean less leeway . Less steering to compensate so less parasitic drag. Unlike fish or fins less risk in skinny water or entanglement as can occur with fins. However for a cruising boat ,especially for light ice class, would prefer retractable fins. A superficial search shows available from Quantum but only for big boats. Still active fins just plan work and can be left on even in the worst conditions unlike fish where there’s some risk or gyros which may meet the limits of precession. If retracted no risk in skinny water, or debris and drag minimal so no appreciable impact on range.
Truly bad weather is fortunately rare. But even a short period wave train is uncomfortable. We are stabilized but use it ~5 no more than 10% of the time. A big advantage of gyros is when bottom fishing. Wonder if anyone here has experience with zero speed fin stabilization? Would seem easy to do with retractable fins or by swapping out a fish for a one way grate.
Of interest in survival conditions ultralight centerboarder with board up faired the best in available records. Thinking is they can slid sideways so less likely to turtle on a steep wave face. Heavy displacement full keeled boats did worst. So comfort doesn’t equate to survivability.

 

[Mac2]

What about the rolling chocks that have a section in the middle that is hinged (opens on the down swing and closes on the upswing)? Im guessing they make noise when they close, but have always wondered if there are advantages. I’ve also seen a Cape Horn with rolling chocks that also had active fins stabilizers in the middle (which also protects the fins nicely).

 

[DDW]

The advantage of a deep centerboard over fins is the leverage would be much greater. It could be made active with a tab or by making it a tacking CB, but that starts getting complicated. I think the reacting force goes up by the square of the depth (1x due to extra leverage to center of roll, 1x more due to apparent flow shift r x alpha). It gets hard to make deep active fins, unless retractable they will ground, and the bearings get much heavier. Pretty easy to make a deep centerboard, a small fraction of the cost of off the shelf fins. A daggerboard is even cheaper, though there is impact on the accommodations.

Hippo - I'm looking at a boat with a Seakeeper. At this point for coastwise, would you spend more to get one with, vs a comparable one without? Doesn't sound like yours gets a lot of use. I also wonder about maintenance on them, bearing replacement is I guess quite pricey.

 

[Hippocampus]

We got pretty use to life on a slant. Also learned to anchor as to avoid swell. Both wife and I are tolerant of low frequency motion. We aren’t upset by heave but don’t like corkscrewing and square wave chop. So our needs maybe not be typical. However think the choice of a gyro for coastal cruising makes huge sense. It’s coastal not deep water that I think you experience more short period chop. Also due to the 1 in eight rule you get more breaking waves of modest height. It’s on power not sail being sailed as it should be that you’re more effected. That 10% of usage is key. It means a days work can be done in comfort. It means bottom fishing and slow trolling can be done in comfort and safety.
Doing the inter coastal the SK was off. We’d turn it on an hour before an open bay. Same when going fishing. Off getting to the fishing ground and on before arrival. Our concern is usually generator time not spin up as we aren’t big AC fans and the boat has good natural ventilation.
But it seems now a days there’s more debris in the water and fish/fins slow you down and use fuel. Here on the east coast you are commonly in less than 16’ of water so fish aren’t practical. You commonly find a spot to anchor with no wind and shifting current so fin entanglement by anchor chain of your fins is a concern. Regardless of choice of stabilization when coastal cruising and not on a schedule most days stabilization isn’t necessary on a SD hull. If conditions are modest adjusting speed is enough. So you want something that doesn’t stick out from the hull, can be deployed only when necessary and is the most effective of available technology in moderate conditions. Gyros are the best fit for SD hulls imho at present.

 

[DDW]

This would be for use in the PNW, so it is mostly sheltered water with the occasional run in unprotected ocean (usually Cape Caution and the Dixon, however we also would use it on the west coast of Van Isle and have some thoughts of a run across the Gulf of AK to Prince William). Most days with our current SD hull (AT34) it is fine without stabilization, as you say you can always speed up a little which helps. There have been days in the Straits of Georgia and up in SE SK in some of the larger water when it would have been nice to have. Hitting something in the water is always a concern in the PNW, it is rare to go a couple of months without hitting at least something, and the danger increases with a seaway as seeing the debris becomes impossible.

I am also a sailor, still have the sailboat in fact. However the motion of the SD hull in a crossing sea is more reminiscent of a catamaran. On the monohull I have never been badly sick, even in the ocean.

Do you know if the Seakeeper 5 has a limit on bearing life? Various sources say 3000 hours or maybe more for later units. Major work on it would appear to be very expensive, as it is heavy and there is no access for lifting equipment. 3000 hours is a long time, but I don't know how much it has been used alread.

 

[Mambo42]

Wonder if anyone here has experience with zero speed fin stabilization? Would seem easy to do with retractable fins or by swapping out a fish for a one way grate.

I have zero speed stabilization, in fact I have stabilization at any speed. That was one of the reasons why I choose the CMC stab 25, it also stabilizes while at anchor or even in the port of marina. The software is written in such a way that it can cancel out roll movement even when the boat is lying dead in the water.
The one thing I notice is that the speed with which the fins react is not always the same. Sometimes they move slow, other times they move fast, sometimes it is a combination of both. I.o.w. the software will decide how fast the fins have to move in order to keep the boat steady and must say that they do their work perfectly.

Our boat has the tendency to always move sideways to the waves, no idea why, but it does. Only when the wind is really strong will the bow move in the direction where the wind comes from. But if there is a light wind the bow won't go into the wind, the boat will just move sideways to the waves and start to roll. And that tendency was one of the reasons why we wanted zero speed fins.
Recently we were in Venice and the water in front of San Marco is very rough due to all the boats criss crossing the water at high speed. One day a year you are allowed to anchor out in front of San Marco, however until 8 PM all the buses, taxis etc keep moving around so without stabilization it is not fun. Us and the boat next to us (a 62 Princess) happened to have the same electric fins. We were lying dead solid in the water, while all the other boats were rolling violently.
Since our fins only react when necessary and they don't use a lot of electricity we basically have them switched on all the time. It is a sort of stand by, they will instantly react when necessary. If there is no disturbance they won't do anything and therefore not consume electricity.

Underway stabilization is also perfect. Electric fins can react faster than hydraulic fins, so they actually keep the boat more steady than hydraulic fins.
Hope that answers your question.

 

[Mambo42]

A comparison between fins (inactive) and rolling chocks is meaningless without a full description of the rolling chocks. Fins are fairly generic in their size and location, rolling chocks on the other hand vary from tiny little strakes a few feet long to a few feet deep and nearly full length. Inactive fins are like short deep rolling chocks. On a centerboard sailboat, you can play with this to some degree, raising or lowering the board. Or with retractable fins.

I've not seen it done, but there is merit to the idea of a deep centerboard in a trawler. It would be at least as effective and probably more effective than batwings, without being an eyesore, would retract into the keel without sacrifice of space, and could be made to kick up when it struck something. Requires no power and minimum attention, though they do require maintenance when hauling (hard to antifoul the case).

I fail to grasp the reason why the fins would need to be retractable, what benefit would that be for us ? You will loose space inside the boat and you set yourself up for more maintenance.
As for hitting something while underway it is not really a problem for me. The fins I have are designed to break off when they hit something and then they will float to the surface. The motor itself, which is flush with the hull, will not receive any damage. Furthermore, the other fin will now do the job of both fins, so you will remain stabilized.
You then just retrieve the fin that broke off, call the company and they will repair the damage. Of course you need to pay for that, but it is not a job that takes weeks. Last year a charter boat came into the marina in Didim, they had exactly that problem. Took the mechanics two days to rebuild the fin and screw it back on, boat was back in service. Real impressive to see the theory in practice.

 

[balder8]

I must admit as said below, that push on a button and let the fins work is really a good thing. I am talking, may be too much, about paravanes rig, "fish" etc because it is really "new" for us in Europe in the small trawler world. But I regognize I only use at 95% my keypower hydraulic fins. Et they are so efficient! Say that issues should be only power failure or hydraulic problem( we have one one time in Med , a solenoid broken on the hydraulic pump) may be not completely true: With so many orcas attacks destroying rudders ( with another sailing yacht sank recently) in South Spain, Portugal coasts, Brittany in France, Gibraltar straits, I was a little bit nervous considering the stainless steel shaft and the design of the polyurethane fins exactly like rudders, which are the target of these bloody orcas... So I add, spikes on all the surface of my two fins. It changed nothing underway but I do not know if this should be enough sufficient to deter orcas trying enjoying pushing these amidship rudders with their nose.
I agree as well with the idea that let a very heavy rig suspended on starboard and portside at 6 meters from the centerboard with an heavy "fish" in rough water is not completely secure.(refer the story of the Nordy skipped by his french owner and sons from US to Med losing one badly installed paravane in the middle of ocean with a rope stucked around the propeller...

 

[Mambo42]

Do you know if the Seakeeper 5 has a limit on bearing life? Various sources say 3000 hours or maybe more for later units. Major work on it would appear to be very expensive, as it is heavy and there is no access for lifting equipment. 3000 hours is a long time, but I don't know how much it has been used alread.

The 3000 hour limit was one of the reasons why I did not chose the gyro (amongst other reasons like electricity usage, spool up time, space in the ER, difficulty performing maintenance).
I guess that if you use the boat only in the weekends and then only in the summer you are not going to get to 3000 hours any time soon.
However, we live on the boat from end of March until mid to end November and we spent most of our time on anchor. We do want to be stabilized while on anchor since many anchorages are open to at least on direction of the wind. Wind tends to change here rapidly, so before you know it your calm anchorage turns into not so calm. Zero speed stabilization then keeps it comfortable. Basically we spend over 7000 hours on the boat each season and if we would have to rebuild the gyro after 3000 hours we would have to do that twice a season. That was no option.

I have heard that the 3000 hours now has improved to 5000 hours, but that would still mean we would have to do that mid season.
On my fins I need to change a seal after 5000 hours, but I have discussed it with the manufacturer and we can postpone until we get out of the water for the winter at the end of November.

 

[Hippocampus]

I fail to grasp the reason why the fins would need to be retractable, what benefit would that be for us ? You will loose space inside the boat and you set yourself up for more maintenance.
As for hitting something while underway it is not really a problem for me. The fins I have are designed to break off when they hit something and then they will float to the surface. The motor itself, which is flush with the hull, will not receive any damage. Furthermore, the other fin will now do the job of both fins, so you will remain stabilized.
You then just retrieve the fin that broke off, call the company and they will repair the damage. Of course you need to pay for that, but it is not a job that takes weeks. Last year a charter boat came into the marina in Didim, they had exactly that problem. Took the mechanics two days to rebuild the fin and screw it back on, boat was back in service. Real impressive to see the theory in practice.

If you want light ice class they seem to be required. Before buying current boat looked at a nordie. She had her starboard fin ripped off when it entangled in her anchor chain. Beyond the fin there was other damage as well. When not in active use fins still produce drag. On ships some retractable fins have enclosures that can be deployed so drag is eliminated. Even without such devices when retracted the fins produce very modest drag. Have gone through the saragasso sea multiple times. It’s amazing how much weed you pick up even when diverting to try to stay just on the edge. The amount of weed has changed in recent years. Now a major problem for Caribbean beaches requiring bulldozers to clear it periodically. Even on sailboats you may need to stop and dive to get it off appendages mid ocean. Been told it’s hard on fins as well. Now with periodic very heavy rains and opening off flood basins, reservoirs, and storm run off there’s a lot more debris in coastal waters. Yes you’re concerned about logs but more typical is mats of branches, weed and grasses. Often they are just below the surface or so prevalent that you can’t reliably dodge them. Really like my SK during those intervals but would think retracting fins would be equally effective.
So for a boat occasionally used coastal retracting fins would be helpful. For a voyaging boat or light ice class the gain in range and ease of satisfying class requirements would be helpful. Your mileage may vary. Loss of interior volume would seem to be not a major loss of usable space in comparison to the benefits.
Each use pattern is different. I don’t use a hammer on screws. Think gyros make sense for mixed mostly coastal use. Think fish if the goal is to decrease expense and complexity and skinny water isn’t in the equation. But for a voyaging boat fins like yours fins remain a great choice. Yes there’s definite benefits to electric if feasible. But there’s also benefits to retractable with certain use patterns.

 

[mvweebles]

Type of stabilization is a personal decision. There are advantages and disadvantages to each type. I understand the case for gyro/Seakeeper but for me, the disadvantages outweigh the advantages and would be very low on my list of stabilization options. Why? I'm not a generator-always boat. If I were, might be a different story.

Not sure what I would chose if I started from scratch. Although I'm currently doing longer distance cruising, that's not the long term plan. Hydraulic fins have a long history of reliable service (and rarely pickup kelp) so it's a pretty high bar to clear. Electric motor fins are intriguing as are Magnus rotors. Would be a tough decision. But for me, I don't see gyros in their current form being a contender. Nothing wrong with them - they just aren't the right stabilization solution for my usage.

Peter

 

[Hippocampus]

Makes perfect sense Peter. Your in a cruising ground with little kelp, less skinny water and debris to my understanding. We are also don’t run the genset often but also don’t need the AC or SK all the time. My only point is as you say a personal decision. Would note on the US east coast an increasing number of vessels from big express cruisers down to little center consoles are putting SKs in. Agree less attractive for boats only running at displacement speeds. But fins are less attractive for boats that plane on occasion and fish make little sense for that sub group.
My conversation with Mambo was aimed at retractable fins v non retractable . Retractable allows the fins to be placed where they have the most effect. Also no problem if they extend past the envelope of the boats hull when fully extended. Would add Quamtum version comes pocketed which to my mind circumvents the downsides. Would further note parts of the boat kept in total darkness and no water flow don’t experience growth. If I was leaving the boat in the water in a marina to return home for awhile would put a black garbage bag over the rudder and running gear. Come back to no growth. Would think leaving the fins retracted and pocketed would have the same result. My experience to date suggests both coastal and ocean most days you don’t need any form of stabilization. After a few days most folks habituate to long period heave and pitch so unless it’s a tender boat prone to roll they do just fine

 

[Dswizzler]

All depends on how you plan to use the boat and where you plan to go. Simple as that. We are not stabilized. Over th3 last ten years we have run from San Francisco to Bocas de toro Panama and back to LaPaz Mexico. Today you can get a great 72 hour weather forecast. I’m retired and don’t need to go out in crappy weather. 95% of our runs have been fine. Twice in ten years I’ve wish I was stabilized when it was uncomfortable, but never dangerous.

So like I said it depends on how you want to use the boat and timeframes.

 

[hmason]

We just made our first ocean run in our stabilized boat. Had numerous boats before without them. Things got rough with beam seas. I was amazed at how steady we were. I'm sold.

 

[rslifkin]

For me, I'd be fine with fins or fish on our current boat. Fish wouldn't be usable at fast cruise, but I'd be fine with that. Roll is less of an issue at that speed anyway (but the difference in fuel burn is big enough that speeding up is an expensive way to improve comfort). Fins would add a little drag at high speed, but it shouldn't be major. And they'd work in either speed range.

 

[DDW]

If you've never spent much time cruising the PNW and SE AK, I can understand not understanding the need to avoid log damage. Out here there are trees, logs, deadheads, debris, and detritus that is a world apart from the east coast US, Med, Caribbean. You are going to hit some of it. The only question is how much damage will be done when you do. And the solution of having someone come fix it doesn't work well, there is no one within perhaps 500 or 1000 miles who can do it. Even the lobster pot problem in Maine, as extreme as it is, is an inconvenience that won't sink the boat. This stuff will.

Now I was talking about a deep centerboard, you will need that to be retractible because the boat will otherwise draw perhaps 10 or 12'. When it retracts, it folds into a trunk in the keel, which is unoccupied space, no impact on the accommodation at all.

 

[Hippocampus]

Not in a position to compare but do know this is a problem in many areas. While on passage from Newport RI to Antigua went from 8.2kts to 3.1kts in the space of less than a couple of hours. Although keel and rudder had a lot of weed worse to get off was on running gear although it was a feathering prop. Returned to 8.2 once cleared. While going through C &D a day after heavy rains stopped hull strikes were continuous. No issue or concerns about sinking with solid grp hull and SK but density was sufficient you couldn’t avoid them.
Still if sinking is the major concern would give thought to a metal hull. If appendages are the concern then gyros or multihulls. If you can tolerate periods of no stabilization then retractable fins or Magnus effect which are usually retractable.
Have only owned small centerboarders. Largest I’ve had exposure to was a 30’ cat boat. Do know they are a PIA to service. Also service or repair not uncommonly requires a haul. Even for little dinghies it’s difficult as you may need to raise the hull high enough to get access to the entire board or go through the exercise of dropping the board out by removing the bearing pin.
People use dagger boards because they need no weight to deploy. Can be very light. Tend to be easier to make hydrodynamically efficient. Often ocean passage making sail will carry a spare. For power don’t know how enthusiastic I’d be about either an in hull trunk enclosed or keel enclosed centerboard. Perhaps a non issue if you’re doing annual hauls and the travel lift can raise you high enough to service. Know I’ve spent unhappy hours cleaning between the board and its enclosure. Unless the board is taken out there’s the forward section thats enclosed and hard to get to. That’s with little boats. Imagine it would be a bear to do with a decent sized cruiser. Unfortunately there’s no free lunch. But before considering this would note all forms of active stabilization are more effective than passive. A centerboard would be passive. So consider would it be worth it for you.

 

[mvweebles]

...... While on passage from Newport RI to Antigua went from 8.2kts to 3.1kts in the space of less than a couple of hours. Although keel and rudder had a lot of weed worse to get off was on running gear although it was a feathering prop. Returned to 8.2 once cleared. While going through C &D a day after heavy rains stopped hull strikes were continuous. No issue or concerns about sinking with solid grp hull and SK but density was sufficient you couldn’t avoid them.

You have some of the worst luck I've seen in boating. I don't blame you for worrying about appendages and GRP. If I'd had your experiences, I'd feel the same way.

Peter

 

[Hippocampus]

Oh think I have excellent luck. Have kept people in the boat, water out and get to my destination. Have had a lot of fun doing it. Unlike several of my friends have missed out of the biggies. Losing a mast, needing significant outside assistance like calling for CG or local SAR, getting hurt, fire or sinking. Had my first tow last year (oil pressure dropped low). Only one very minor collision (friend ran his Outbound into my docked Outbound-minor gelcoat damage). So overall think I’m doing pretty good. But think there’s old sailors. Bold sailors . But few old,bold, sailors. Sure you have more stories than me as you have a huge store of experience. Just try to relate the need for caution here and offer stories to tell why from the bone headed moves I’ve done. Thought I could skirt the saragasso. Was warned by friends it’s changed and there’s a massive amount more weed now and it drifts south. Found out the hard way. Oh well….

BTW have no experience of PNW so low level of concern about a boat sinking log or other flotsam strike sinking the boat. Been happy in solid grp for now. Was just addressing his concern.