Reducing roll while anchored or moored.

[mvweebles]

Peter, please see my comments below.

Yikes Fletch! You could have been seriously injured. It was that kind of thing that made me listen when a past colleague lured me back into corporate America. One of the dumbest things I ever did on a boat was I was aboard the first N72 at the dock in Dana Point. She was in the middle of full commissioning with stuff all over. Just as I'm reading the last hand written words in big black magic marker on a 2'x3' piece of cardboard, Im suddenly free-falling into a cavernous bilge, a good 7-foot decent. Totally wound my clock - stars, bird tweeting, the whole loony tunes routine. BTW - the cardboard sign said plainly "CAUTION. OPEN HATCH!!" Was the last thing I saw before the stars and birds tweeting. Much as I loved delivering, I worried about getting hurt and being unable to work.

Thanks for the update on the sea keepers. People as from time to time and I like to give honest feedback when I have none of my own. So far, the only complaints I've heard are likely due to undersizing the system due to cost. Can't blame the system for that.

Peter

 

[mvweebles]

Fletcher, you are certainly entitled to your opinion but i have been on a 42' boat, at anchor that had a SeaKeeper Gyro running. The noise from the generator + the Seakeeper was irritating at best & the cost I was referring to was the purchase price and installation of the gyro. No matter how you slice it, it's expensive to buy & install! When "working on facts", let's not leave the most expensive part of a Seakeeper out of the conversation!

David Gerr has done some definitive work on stabilization. In short, he claims stabilization does not improve a boats inherent stabilization, it just makes it more comfortable. If true, and if safety is #1, there's an argument that any effort at stabilization is wasted money.

People do not spend rationally on boats. Expense does not always equate to poor value. The sea keeper system is not a fit for many boats and many owners, and they are out of my realm for many reasons (expense being just one). But my suspicion is they sell a lot of systems just by getting people aboard and flipping the switch on. For those people, they see value. I can't fathom some of the money people spend on boats - lord knows I won't admit to myself the money I've spent refitting Weebles. Sometimes, fiberglass and diesel suspends rational thought. When I was younger, same thing happened with women.

 

[Fletcher500]

Fletcher, you are certainly entitled to your opinion but i have been on a 42' boat, at anchor that had a SeaKeeper Gyro running. The noise from the generator + the Seakeeper was irritating at best & the cost I was referring to was the purchase price and installation of the gyro. No matter how you slice it, it's expensive to buy & install! When "working on facts", let's not leave the most expensive part of a Seakeeper out of the conversation!

I can tell you that on our boat which has very good insulation between the engine room that the noise of the Gen and Gyro are barely discernible so your lunch time visit on another boat to form an opinion is different from mine after having one for 2.5 years and about 450 hours of use. Regarding cost, the Gyro I purchased was similar, if not less than the cost of fins. Yes, you are entitled to your opinions, but not your own facts.

Edit, I paid $25K for a SK5 unit and a very minimal install cost but there was no mark up as we were the first Helmsman to get a Gyro. How much do fins cost Codger?

 

[Slowmo]

Over a year ago, there was considerable discussion about using "rolling chocks," which are basically longitudinal "fins" on a hull. A good discussion here, esp. the link to an article: https://www.trawlerforum.com/forums/s3/bilge-keels-43050.html


Despite the generally favorable comments regarding them, I'm at a loss why most later discussions about boat stabilization don't include them. It seems people prefer much more expensive and/or troublesome products to use. I've been reading a lot about power boating. Flopper-stoppers seem a big hassle to deploy and retrieve in some videos I've seen, that is if you're using them underway, and I don't understand using them solely at anchor.


Powered stabilizers and gyros are far too expensive and troublesome imo. Why not install or spec out rolling chocks for your boat, whether an addition or in a build? Seems to me the cheapest, best, and most effective way to stabilize your boat, either at anchor, or underway.

The 'fins' you refer to were known as bilge keels (or bilge boards) and were commonly used on round bottom boats into the 1950's. If you look at old cruisers and yachts you'll often find them. I think they stopped being used for a few reasons. First was the move towards hard chine boats. The turbulence generated by a roll with a hard chine damps the roll more than a round bilge. Second, it is really hard to optimize a bilge keel to prevent it from causing a lot of drag. The problem is that the bilge keel should follow the direction of water flow around the boat. That's easy at the keel but fairly hard the further off center you go. also changes with speed. Third is that in the old days we didn't use travel lifts. Obviously a bilge keel would create a stress point in a sling.

The concept has been used more in sail boats in recent years, mainly in Europe, to allow them to stand up when they sit on the bottom with the extreme tides they can get. Of course these tend to be short and deep rather than shallow and long.

I really considered them for our old round bilged wood boat but rejected the idea for the reasons above. We did a keel extension, but still rolled our scuppers under in some conditions.

 

[RickyD]

We have a Gyro that is on whenever we are running the boat. I only run it while stationary if conditions are very bad for environmental reasons.

I have been thinking of a flopper stopper for a few years now and watching the guy next to me the past week rolling a heck of a lot less than we are, it’s time to do it.

I know extending it away from the boat horizontally like sailboats do with their boom is best to get a larger Moment arm to resist the boat rolling. But my plan is to just hang one on a midship cleat, possibly both sides.

The folding plates shown below appear to be the most popular, but I have seen people use the stacked ones as well.

Thoughts as to the best solution, or other products out there I may be missing?

The Stainless "butterfly" style is popular but I have not used them. The red "Hats" suck. Hard to stow and they flutter down to slowly. I just rebuilt my old ones. The company was small and now out of business. They are two steel frames with rubberized coating. The two screw together with heavy plastic panel sandwiched between. The plastic sheet is cut like an X corner to corner. The bottom frame has a steel lattice work to prevent the plastic from not presenting a flat surface when pulled up through the water. Then the X flaps open to allow the water to pass on the downward cycle. They work great and they don't make any noise in operation. I have two davits and suspend them off of. Rocker stoppers are said to work best when suspended from the same side with as much leverage as possible.

 

[mvweebles]

I can tell you that on our boat which has very good insulation between the engine room that the noise of the Gen and Gyro are barely discernible so your lunch time visit on another boat to form an opinion is different from mine after having one for 2.5 years and about 450 hours of use. Regarding cost, the Gyro I purchased was similar, if not less than the cost of fins. Yes, you are entitled to your opinions, but not your own facts.

Edit, I paid $25K for a SK5 unit and a very minimal install cost but there was no mark up as we were the first Helmsman to get a Gyro. How much do fins cost Codger?

Pretty sure fins would be in the $35k-$40k range plus install. $25k for sea keepers was a steal. Doubt that could be replicated. The YouTube folks on Sea Venture looked at sea keepers for their 55 foot Cheoy Lee (I think) and if I recall, cost was pushing $100k. They went with paravanes.

 

[Fletcher500]

Pretty sure fins would be in the $35k-$40k range plus install. $25k for sea keepers was a steal. Doubt that could be replicated. The YouTube folks on Sea Venture looked at sea keepers for their 55 foot Cheoy Lee (I think) and if I recall, cost was pushing $100k. They went with paravanes.

The price for fins you note is about what I have heard. Again, fins are great, but for various reasons we decided a Gyro was a good fit for what we were doing. The SK5 I got is an older generation unit, so they are priced fairly reasonably. The SK6 is priced more aggressively, but you supposedly get 20% More torque. The SK9 is probably what you are referring to for the Chevy Lee. The last I heard the SK9 was retailing for $75K, but that was awhile ago.

Ok, that is it for me in regards to Gyro’s, unless Codger wants to debate some more. I am not opposed to discussing the subject, but would prefer people keep it factual and not based on what they heard at the dock, or little to no interaction with a product.

Thanks all for the feedback on the passive methods of roll reduction.

 

[mvweebles]

The price for fins you note is about what I have heard. Again, fins are great, but for various reasons we decided a Gyro was a good fit for what we were doing. The SK5 I got is an older generation unit, so they are priced fairly reasonably. The SK6 is priced more aggressively, but you supposedly get 20% More torque. The SK9 is probably what you are referring to for the Chevy Lee. The last I heard the SK9 was retailing for $75K, but that was awhile ago.

Ok, that is it for me in regards to Gyro’s, unless Codger wants to debate some more. I am not opposed to discussing the subject, but would prefer people keep it factual and not based on what they heard at the dock, or little to no interaction with a product.

Thanks all for the feedback on the passive methods of roll reduction.

Nice close Fletch. I'll wrap by saying the expensive decision is active stabilization vs paravanes. Either fins or Sea keeper, it's a premium. Choosing between them is a matter of (1) do you have room? Seakeepers are very popular for new builds, not so much for retrofit. And (2) are you okay with 24/7 generator running? Ken Williams Blog on his recent build of a new GB60 was interesting. He flatly states they are a full time generator boat. For that, Seakeepers make more sense.

Honestly, given the cost of active stabilization, the additional cost of Seakeepers over fins is likely not a deal killer for most buyers. As a matter of fact, I understand some new build owners are opting for both.

Peter

 

[kapnd]

We anchor in protected areas of the ICW. If we are ever rocking at anchor my wife makes a few dark and stormy’s and before long you don’t even notice the rocking. Much cheaper and a hell of a lot more fun than stabilizers!

Nailed it!
I can often reduce rolling by moving the anchor line to a “quarter” position, and the rum bottle is always willing to help.
People who don’t like the motion of the ocean could always take up golf!

 

[Codger2]

Ok, that is it for me in regards to Gyro’s, unless Codger wants to debate some more.

No, not interested in debating someone who thinks his experience is the only experience!

 

[Fletcher500]

No, not interested in debating someone who thinks his experience is the only experience!

You are posting sound bites with cute emogees and they are not always accurate. I know the current trend is to speak loudly, and facts don’t always matter, but to many of us they still do.

 

[Codger2]

You are posting sound bites with cute emogees and they are not always factual. I know the current trend is to speak loudly, and facts don’t always matter, but to many of us they still do.

Wow! I thought you were done! Can't believe anyone these days who says they have all the facts!

Let me try that! I am definitely done!

 

[Fletcher500]

Wow! I thought you were done! Can't believe anyone these days who says they have all the facts!

You forgot an emogee.

 

[markpierce]

Seems like some don't like the feeling of being at sea.

 

[Fletcher500]

Seems like some don't like the feeling of being at sea.

Funny, from a guy who boats in the Delta. How many times have you gone under the Golden Gate Bridge in the past 5 years and actually been to “sea”? And that doesn’t count your trips on cruise ships which you like to talk about.

 

[rslifkin]

Seems like some don't like the feeling of being at sea.

Some of us also anchor in places where the constant wakes from passing traffic on weekend days gets to be a bit much at times.

 

[Ka_sea_ta]

Could a person use the dingy crane and attach the Flop stopper to the winch cable and swing the crane outboard and lock the crane in place and lower the flop stopper to correct depth?

 

[Retriever]

Regarding Seakeeper noise...

I took a demo ride on a Nordic Tug 39 with a Seakeeper. At the time I owned the same boat and I was blown away by the difference in ride. It was a nasty day, gusting to 50 knots in Rosario Strait, and the boat was remarkably stable even at rest.

I didn't notice much noise from the Seakeeper. Not that it's silent, but it blended in seamlessly with the general machinery and water noise when underway. The boat wasn't noisy, either.

My biggest problem was cost (compared to the value of my older NT) and, to a lesser extent, time to stabilization.

 

[bogranjac1]

Could a person use the dingy crane and attach the Flop stopper to the winch cable and swing the crane outboard and lock the crane in place and lower the flop stopper to correct depth?

Yes,that's a good idea Ka_sea_ta.
A good starting point for realising the benefits of flopper stoppers at anchorage to reduce roll.
You will find just one flopper has a noticeable effect.
Later you may like to employ a setup like mweebles for greater comfort.
The floppers can easily be retrieved by a light rope attached to the plates and then secured to the gunnals or railings without any serious lifting. They just swing in towards boat and easily secured.
Just or the sake of semantics - flopper stoppers - to reduce roll at a boisterous anchorage.

 

[Hippocampus]

A newbie question. Have expanded the search to include a DD382. It’s a hard chime boat with neither fins, fish nor sea keepers. Any thoughts to get a sense how different motion at anchor is on such a full displacement hard chine boat is c/w other vessels? Are we stuck with learning from experience and adding stuff after purchase if necessary or can we feel it’s highly likely this will be unnecessary given characteristics of this design?

 

[rslifkin]

In general, hard chines will tend to not roll as far, but will typically roll a bit faster and have more of a snap back at the end of the roll. Whether that motion is more or less comfortable is a matter of preference. If you're used to sailboats, it may be a strange feeling to adjust to.

 

[Mako]

I know extending it away from the boat horizontally like sailboats do with their boom is best to get a larger Moment arm to resist the boat rolling. But my plan is to just hang one on a midship cleat, possibly both sides.

Fletcher it sounds like a nice easy solution that should result in some roll reduction without having to resort to a very cumbersome rig. However why don't you consider fabricating a 3ft strut that hangs off the gunwale. By increasing your moment arm such a small amount you can increase the effectiveness by almost 50% (10ft leverage arm versus 7ft leverage arm).

If you're not a welder then just have a local weld shop throw something together in mild steel, that way you can experiment with the design before finalizing in SS.

 

[Slowmo]

A newbie question. Have expanded the search to include a DD382. It’s a hard chime boat with neither fins, fish nor sea keepers. Any thoughts to get a sense how different motion at anchor is on such a full displacement hard chine boat is c/w other vessels? Are we stuck with learning from experience and adding stuff after purchase if necessary or can we feel it’s highly likely this will be unnecessary given characteristics of this design?

Hard chines generate turbulence during a roll so naturally damp the roll more quickly than a round chine design. Things like roll period and snap back are determined by other factors including displacement, hull form, and weight distribution. Naval architects design the weight distribution in a boat to manage these factors (ballast, tanks, engines, superstructure). For example, a sailboat without a mast has a rapid roll with hard snap back because it needs the weight of the mast to balance the weight of the keel. In fact, this is why dismasted sailboats are far more likely to be rolled over. You really have to be on a boat to know what kind of motion it has. Our hard chine V-bottom has a slow roll with gentle snap back (Ed Monk did his job well).

 

[mvweebles]

Hull-form plays some roll in at-anchor comfort, but unless you're talking a Cat, the big issue is just finding quiet anchorages. Several of the folks on this thread are in the SoCal area. Best cruising grounds are Catalina/Channel Island, which are notorious for running a constant swell, even on the protected side of the islands. Anchorages along the West Coast are few and far between. Those that exist tend to be open roadsteads that almost always run a swell. Eventually, almost any boat will get in-phase with the swell and end up on its beam-ends.

 

[Woodland Hills]

These look interesting.

FlopStopper.com

Holy crap! That’s expensive. $800+ for one.....

 

[Wxx3]

Haven't personally tried it but using a Seabrake as an ad hoc flopper stopper was recommended to me. Lighter and easier to store than the typical options but I was always a bit sceptical about how fast it would sink on the down cycle.

https://boatcrewgear.com/burke-seabrake-drogue/

I did try something like this ONCE. It really didn't work, as it would not sink fast enough.

 

[Hippocampus]

Thanks guys. We’ve lived with”north swell” for the last 7 years in the eastern Caribbean. Take home is you have to live with a boat for quite awhile until you get to know her..
BTW cats can hobbyhorse. Facing a short chop can be unpleasant even at anchor.

 

[Wxx3]

The Stainless "butterfly" style is popular but I have not used them. The red "Hats" suck. Hard to stow and they flutter down to slowly. I just rebuilt my old ones. The company was small and now out of business. They are two steel frames with rubberized coating. The two screw together with heavy plastic panel sandwiched between. The plastic sheet is cut like an X corner to corner. The bottom frame has a steel lattice work to prevent the plastic from not presenting a flat surface when pulled up through the water. Then the X flaps open to allow the water to pass on the downward cycle. They work great and they don't make any noise in operation. I have two davits and suspend them off of. Rocker stoppers are said to work best when suspended from the same side with as much leverage as possible.

I was given a pair of these from a S/V who said they didn't work very well.
His boat was lighter than Dauntless.
This set was about 30" on the diagonal (I assume there different sizes made).

I tried them and they didn't work for me either, though I agree the design seems very good. I think just too small for a 45k lb boat with a really round bottom.
If I was any place else on the west coast, it would be a top priority and I would probably have a larger pair made.

I've also considered large garbage barrel with holes in the bottom.

 

[rslifkin]

In general, boats with slower roll periods will need bigger surface area to damp roll adequately. Boats with fast roll periods will need less surface area, but the flopper stoppers will need to be able to drop faster, or they won't be fully re-set before the next roll starts.

 

[mvweebles]

Holy crap! That’s expensive. $800+ for one.....

Right???

Here are some pics from Steve Dashew's site. Shows the style of Flopper Stopper I have. Around 2000, I lost one at Cojo Anchorage east of Pt Conception near Santa Barbara. I replaced it for about $100 at the time from a guy in San Diego, though they are no longer made. I would think the FlopStopper shutter-design would be slightly better, and it can be disassembled for easy storage. But I have been happy with the one shown in the attached for many years.

For those on a real shoe-string, Larry Pardey suggested using a milk crate with heavy fabric as the 'valve.' I have a few heavy milk-crates with a steel rod around the rim that would probably work well, and has the benefit of serving double-duty.

https://setsail.com/how-the-flopper-stoppers-work/

Peter