Flopper Stopper - design ideas?

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mvweebles

mvweebles

Guru
Joined
Mar 21, 2019
Messages
7,218
Location
United States
Vessel Name
Weebles
Vessel Make
1970 Willard 36 Trawler
Looking for ideas for at-anchor flopper stoppers. Goal is something easily deployed and stout to replace my current original equipment setup that is definitely stout but a PITA to deploy. Not looking for a paravane setup, but not looking for a dinky Magna setup either.

Current on my 1970 Willard 36 is a pair of 3" spinnaker poles - must be 12-long each - fixed end is a traditional spinnaker snap into a 2" SS loop on the side of the bonnet. They tuck nicely against the flybridge bonnet when not in use but require quite a bit of rigging at each use. I could go a few years and not need them, but when I need them, seems like I'm in places where open roadstead anchorages are all you get so I use them constantly. On paper, rigging should be a snap. In practice, rigging a fairly heavy pole that is pretty long and hangs well over the side decks is difficult. Greased pig comes to mind.

Best stowage is for poles to lay horizontal along the flybridge bonnet (versus vertical similar to paravanes). What I could use input on is the hinge and support configuration to avoid free-end rigging. Could also use suggestions on better materials, perhaps smaller sized aluminum with more adaptive end fittings.

Any real world examples out there?
 
Larry M said:
Forespar has one of the better systems from what I can tell. I know of a Nordhvan and a KK42 that had them. They seem to store well when folded back.
Click to expand...

Now that you mention, I seem to recall many/most Nordhavns had a slick FS setup. The Forespar URL has very little info on the setup and the fittings (pics are pretty bad). Larry - your avatar pic of your KK42 has FS set. Are you happy with the setup?
 
mvweebles said:
Now that you mention, I seem to recall many/most Nordhavns had a slick FS setup. The Forespar URL has very little info on the setup and the fittings (pics are pretty bad). Larry - your avatar pic of your KK42 has FS set. Are you happy with the setup?
Click to expand...

Whoops - those might be fishing outriggers Larry.
 
Magma makes an effective one. I've seen several boats with them deployed and they seemed to work quietly.

I would not use Magma's poles however. From observation, they are difficult to put out.

One boat hung the Magma roll stopper from a boom and another from the para vane poles.
 

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mvweebles said:
Whoops - those might be fishing outriggers Larry.
Click to expand...

Paravanes that we use a anchor as flopper stoppers. :)

You’ll like the flopper stoppers. We spent 5 years on the Pacific coast between Mexico-Panama and lot of the anchorages are exposed to the western swell. They were key to improved comfort.

There were different rigs to get the actual flopper stopper out away from the boat but the majority of cruisers used the Magma “Rock n Roll” stabilizer.
 
A photo or 3 of the existing setup, mounting pcs., and out configuration might help.
Maybe not but without a photo it is ALL guesswork.
 
C lectric said:
A photo or 3 of the existing setup, mounting pcs., and out configuration might help.
Maybe not but without a photo it is ALL guesswork.
Click to expand...

Attached are a couple pictures. It's essentially the Forespar setup, just not quite as elegant. Old-school spinnaker pole connections. Forespar's website gives only basic info with a hand-sketch showing a single topping lift and two down-hauls to triangulate. On paper, makes perfect sense. In practice, awkward to rig as the free end flops around and is pretty unwieldy (keep in mind, this is all happening for a reason - rolly anchorage). I'm having a robust hard-top installed so might be able to run twin topping-lifts, which should ease deployment considerably. Like the KK owner, I too have cruised the Pacific and believe at-anchor stabilization is a must-have. Obviously, I have the in-water part (similar to the Forespar or the other Flopper-stop item someone linked).

I have also toyed with having an A-Frame fabricated of 1-inch SS on a hinged base of 18-inches - would obviously be stowed upright similar to Paravanes, but would be much lighter duty and smaller. If I make the hinges removable, the arms could be stowed during long stretches of non-use.

Thanks in advance - I was just hoping to query TF's 'bigger brain' to see if there were other cool ideas I hadn't thought of.

Flopper Stopper.jpg

Trailboard.jpg
 
I have hung my inflatable off the side of the boat just barely touching the surface from my boom on occasion.... and it has worked OK.


Trying new dingy davit setup that will use the same hanging rig so may try it some more and experiment.
 
Some of the boats in the Carib that try to hide behind too small islands like ST Barts simply use a second anchor to haul the bow around to point into the swell.

Stops the rock & roll , but the up & down remains.
 
We've thought about adding FS's to our boat, and I'd be inclined to seriously consider something homegrown, except for the underwater pieces.

Obviously, the longer the poles, the more effective the flop stopping action, but could the same result not be obtained with shorter poles (easier to deploy and store), and bigger underwater parts? I wonder how much each foot of pole length contributes to stability. Now that I think of it, there's probably a math formula that would give a pretty good estimate of all of this, taking into account the length of the poles, the size of the underwater piece, and maybe the weight of the boat? Any math majors out there?

(Update: I just looked at the FlopperStopper website, and they say theirs is effective even when deployed from a side cleat, so NO pole. If that's true, then even a very short pole - 3 feet or so - should make it much more effective. Intriguing.)
 
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No math, but suppose would need to know more about what you're stabilizing anyway. My boat is full displacement round bottomed, so more inclined to initial roll than a wide, flat Tiara of same length

My friends 52-foot horizon power cat is 28-feet on the beam, maybe a tad less at the waterline. She does okay with beam waves in an anchorage.

My flopper stoppers are over 32' wide, tip to tip. The underwater "flaps" are probably 4sf or more. I plan to shorten the poles considerably (3' or so) as I just can't imagine that amount of stability is needed.

Because the flaps all have one way gaskets that close on the up stroke, there is more stability going on than simple long lever arm. I really don't think it would take much. I see your boat is a 52-trawler. If you're committed to do this (and its a no-brainer for me), buy the "flaps" and experiment with 2x4s to see what works. Or use Seldane telescopic whisker poles that are adjustable.
 
mvweebles said:
No math, but suppose would need to know more about what you're stabilizing anyway. My boat is full displacement round bottomed, so more inclined to initial roll than a wide, flat Tiara of same length

My friends 52-foot horizon power cat is 28-feet on the beam, maybe a tad less at the waterline. She does okay with beam waves in an anchorage.

My flopper stoppers are over 32' wide, tip to tip. The underwater "flaps" are probably 4sf or more. I plan to shorten the poles considerably (3' or so) as I just can't imagine that amount of stability is needed.

Because the flaps all have one way gaskets that close on the up stroke, there is more stability going on than simple long lever arm. I really don't think it would take much. I see your boat is a 52-trawler. If you're committed to do this (and its a no-brainer for me), buy the "flaps" and experiment with 2x4s to see what works. Or use Seldane telescopic whisker poles that are adjustable.
Click to expand...

Excellent info - thanks! I like the idea of experimenting with some 2x4's.
 
As Brian mentioned, we have had the OceanTorque ones for a couple of years now and use them pretty much every time we go out. Simple and effective, and the stainless poles dont seem to detract badly from the appearance of the boat..

Hamish.
 
Brian,
have you worked out how these would attach on the MK1. For example, are you planning to install the deck mount on t he cap rail or side. I liked the look / reviews of these but was a little concerned that it didn't seem to need as high a topping lift as most other versions (for example, the Forespar Roll-X Flopper Stopper). This seemed to make for an easier installation but I was under the impression that the topping lift took the most strain and was quite critical.
 
Hi Robert

I have only had a cursory look at installation at this point. I'll get my usual contractor down at Gold Coast City Marina involved when it come times to do it. But I'm thinking of mounting on the side so that they can be stored against the hull, just above the rub-rail, which is at the level of the side deck. Then the topping lift can connect at the level of the pilothouse roof, which will be a strong point, and well above the end of the boom even with the boom angled up.

I'll take advice on it, but I think 2.5m booms and size 4 stabilisers will be enough. I base this on having a drogue hanging off my dinghy crane one night last year, only about a metre outboard and on just one side, and being surprised at the benefit. I will be happy to dampen and attenuate the roll at anchor enough to stop stuff sliding around on bench tops! I don't need it to be as flat as the Naiad's make the boat when underway.
 
Thanks. Will certainly be interested in your eventual design. Hadn't thought of storing them horizontally but that may actually help accessing the pole ends if they align about near the swim platform. Whether the attachment is fwd or aft of the side gate might be a consideration (don't want a trip hazard over the gate) but probably determined by where the strongest point to attach on flybridge is.
 
My current setup has the poles attached to the flybridge and stowed aft a d horizontal into chocks. Forespar site shows one topping lift and two down hauls, one to bow, one to stern of boat. From experience, swinging the pole out with a single topping lift can be unwieldy. I have changed from a mast to a hard top and can now use two topping lifts and a single down haul which I hope will be easier to rig.

Based on another posts challenge, I did find a drag-force calculator. 20"x30" plates generate 20kg resistance at 0.3 m/second of drag and increase exponentially to 55kg at 0.5 m/s. Finding the mechanical advantage is more difficult as the effective fulcrum changes as the boat rotates, but believe it to be 5:1 or so with 12-foot poles mounted 2-feet inboard along the flybridge brow. Forces are in the 100kg - 300kg range as I don't believe there would be much "snatch" load with two FS. Less if spread across two topping lifts as I suggest, and of course if pole length is reduced as I will do, it's reduced further.
RobertLeatch said:
Thanks. Will certainly be interested in your eventual design. Hadn't thought of storing them horizontally but that may actually help accessing the pole ends if they align about near the swim platform. Whether the attachment is fwd or aft of the side gate might be a consideration (don't want a trip hazard over the gate) but probably determined by where the strongest point to attach on flybridge is.
Click to expand...
 
I traveled the South Pacific islands on my trawler MV SeaWitch in 2018 and I've been in many rolly anchorages. I tried first the https://www.forespar.com/products/roll-stabilizer-flopper-stopper.shtml type. The results were satisfactory, but not perfect. These were working kind of OK, but the issue with them is that they need about one foot of up/down motion fully engage. by that time with the mass of the boat the roll momentum is significant and it takes little longer to overcome and stop. So the motion was dampened but not stoped. the roll was reduced to some level, but when it gets extremely rolly, they often tangled and I had to get up in the middle of the night to pull one out and untangle. quite often after one is tangled, the other one follows as the motion even becomes more severe with only one of them working.

I was fed up with dealing with the issues and not been comfortable, and I made myself different type. This type of flopper stoppers takes few inches of up/down motion to engage (almost immediately due to the small mass of the venetian blinds type of light aluminum flopping parts. They are light and have more area than the first type, plus they are designed to disassemble and store as a 3 foot bundle when underway. They had area of just under 9 square feet each when assembled 36"X34". See the attached picture.

They were easy to make and even of them performed better than both of the old type. Considering that my boat is 60,000lbs and the beam is 14 feet with poll length of about 12 feet for total of 19 feet of center, I believe that they had the best performance one could wish for. The boat roll was practically brought to minimum and even if very rolly anchorages, we were steady as a rock. Plus there was no more frequent tangling issues.

So if you are looking for something that is tried and true, this is it! you can buy them already made here: http://www.flopstopper.com/FlopStopper/Home.html

Cheers!
 

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SeaMaster101 said:
I traveled the South Pacific islands on my trawler MV SeaWitch in 2018 and I've been in many rolly anchorages. I tried first the https://www.forespar.com/products/roll-stabilizer-flopper-stopper.shtml type. The results were satisfactory, but not perfect. These were working kind of OK, but the issue with them is that they need about one foot of up/down motion fully engage. by that time with the mass of the boat the roll momentum is significant and it takes little longer to overcome and stop. So the motion was dampened but not stoped. the roll was reduced to some level, but when it gets extremely rolly, they often tangled and I had to get up in the middle of the night to pull one out and untangle. quite often after one is tangled, the other one follows as the motion even becomes more severe with only one of them working.

I was fed up with dealing with the issues and not been comfortable, and I made myself different type. This type of flopper stoppers takes few inches of up/down motion to engage (almost immediately due to the small mass of the venetian blinds type of light aluminum flopping parts. They are light and have more area than the first type, plus they are designed to disassemble and store as a 3 foot bundle when underway. They had area of just under 9 square feet each when assembled 36"X34". See the attached picture.

They were easy to make and even of them performed better than both of the old type. Considering that my boat is 60,000lbs and the beam is 14 feet with poll length of about 12 feet for total of 19 feet of center, I believe that they had the best performance one could wish for. The boat roll was practically brought to minimum and even if very rolly anchorages, we were steady as a rock. Plus there was no more frequent tangling issues.

So if you are looking for something that is tried and true, this is it! you can buy them already made here: http://www.flopstopper.com/FlopStopper/Home.html

Cheers!
Click to expand...
You make a good point - how long does it take to engage? I wish I had a picture of my plates, but they are about 24x36 rigid frame with a few cross bars.
with a thick plastic diaphragm that has an X from corner to corner so there are four triangular relief pieces. They work well, but not as well as the aluminum shutters in this design. Mind do not allow as free of an opening and take about 6 inches to slam shut. Of course, they were about $65 when I purchased them 20-years ago.
 
Maybe they are just not updating their web site but Ocean Torque's site is from 2910/2011. Has anyone ordered these in the past several years?
 
BrisHamish said:
As Brian mentioned, we have had the OceanTorque ones for a couple of years now and use them pretty much every time we go out. Simple and effective, and the stainless poles dont seem to detract badly from the appearance of the boat..

Hamish.
Click to expand...

Thanks for the recommendation Hamish, they look like a good product. Do you remember the cost all up, supplied and fitted? Cheers
 
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