Flopper stoppers

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Insequent

Insequent

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Insequent
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Ocean Alexander 50 Mk I
There have been a few threads on stabilisation discussing passive options (batwings, rolling chocks, paravanes) for reducing roll underway, and many will also reduce rolling at anchor. But there are also some simple devices for reducing roll at anchor only, that cannot be used underway. One such option is the Magma Rock 'n Roll device.
https://www.defender.com/product.jsp?id=726630

I have heard they need a little extra weight to sink faster, but otherwise are excellent for their purpose.

Has anybody had any experience with one of these?
 
Last edited:
The only ones I've used are the orange cones. Anything that gives resistance on the upward roll and can reset fast enough on the down roll will work. The more resistance and better it resets, the more it'll reduce roll. Low stretch lines help and poling them out for more leverage helps as well.
 
I had no luck with the orange cones (four on each side, deployed with a 10lb mushroom weight.

I bit the bullet and got a flop stopper - way better. Using it right now and for the last 2 weeks. I might get another, or rig up a way to pole it out - SoCal is rolly.

https://www.flopstopper.com/FlopStopper/Home.html
 
Previous discussions have noted that the orange cones are almost useless. I have no interest in them.

The FlopStopper looks good, but would end up as a quite expensive item when delivered to Australia.

I'm particularly interested in the Magma ones as they are available locally, albeit out of stock at present.
 
I once had a Magma flopper stopper which I used at Fort Jefferson anchorage in the Dry Tortugas. Two would have been better than the single I had. The one I had came with a telescoping aluminum pole which was anchored in a socket permanently installed on the side of the boat with guy lines fore and aft as well as a topping lift line back up to a high point. If you don't have a stout system to get it out front the side of the boat, you are not going to have much luck with it.
 
Thanks Rich.

I am having a custom 8' pole fabricated as the Magma telescoping aluminium pole does not look all that suitable IMO. That work is in progress. What is suspended from the pole to do the work is yet to be finalised. Here is another local option that does work well, but they are a bit heavy and awkward to store when not in use, and they are also expensive.

https://www.boatstabilisersaustralia.com/products/flopper-stoppers-anti-boat-roll-device/

I will install two, one each side. It sounds like it was OK for you, but not great, when you used it. I am interested to know whether it sank quickly enough, and opened quickly enough on the upward movement.
 
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Brian,
I had the Magma flopper stoppers on Tidahapah.
I added some weight by welding a 1/2" s/s bar along the lower edge in the turn out (either side) and also a 1/4 " s/s round on the outside edge.
This did improve their performance. My main complaint was trying to stop them spinning.
On new boat going for a small set of the boat stabiliser australia round ones.
Have purchased a small ex southern cray boat. 39' ( a project to keep me out of trouble now that Tidahapah is sold)
 
Insequent said:
There have been a few threads on stabilisation discussing passive options (batwings, rolling chocks, paravanes) for reducing roll underway, and may will also reduce rolling at anchor. But there are also some simple devices for reducing roll at anchor only, that cannot be used underway. One such option is the Magma Rock 'n Roll device.
https://www.defender.com/product.jsp?id=726630

I have heard they need a little extra weight to sink faster, but otherwise are excellent for their purpose.

Has anybody had any experience with one of these?
Click to expand...


Whitworths will probably be cheaper

https://www.whitworths.com.au/magma-the-rock-n-roll-boat-stabiliser
 
Thanks Benn

Firstly congrats on sale, and best wishes for "smooth sailing" while getting your new boat up to where you want it.

I had not thought about spinning as an issue. Perhaps a light line from one of the 4 attachment points would stop it. I may get Sean to modify mine (if/when I get them) the way you describe right from the start. I really can't see how they could sink to their full extent without some added weight. Alternatively i could suspend a hefty downrigger sinker-weight underneath, from the four attachment points. Doing that I could experiment a little with how much extra weight is needed.
 
We recently installed the round australian ones (https://www.boatstabilisersaustralia.com/products/) Expensive but very well made. Have used them about 20 times on our trip from Hervey Bay to Townsville and they definitely work well. Hard to quantify but subjectively at least 75% reduction in roll in most situations. We had them installed on 3 meter poles (stored lying horizontal along the rub rail). Takes some practice to deploy but not hard once you've done it a few times.
 
Hi Robert

Glad you are getting to use them! I do think they are a great design, once launched. Do you have a weight for each one? They look very well made, and almost a work of art.
But I am thinking they must be quite heavy. And also awkward to store with that post on the bottom where the extra weight attaches.
 
Brian
We store them disassembled (essentially the flat disc and all the other parts seperatly) They are very easy to take apart - the center rod is held in place by an R pin, the bottom weight by quick release shackles etc. For deployment we build them supported on a pulley from the flybridge. There's some photos and blog about them here. https://poseidonoa50.com/weve-got-flopper-stoppers/
We are planning to beef-up the bulwark where the pole attaches (long story...) just to be sure but no issues so far (though only in good to medium conditions)
 
Brian,
Yes I attached a line to the aft inner corner of the flopper stoppers to stop them spinning. Not to tight and it appeared to work quite well.
 
Robert
I'm planning on locating my pole a little further forward than you did, but also lay it along the rub-rail. We plan on a 2" curve in it so it fits flush against the hull all the way along. It wont protrude above the sill of the side door. The "gooseneck" attachment will have teflon bearings in it. I don't want any rattles! I can remove the forward ER vent to give access to the inside of the bulwark in that location to install a block to allow through bolting. In that position the line attached to the stopper can attach to the side returns of the pilothouse roof. This will be an angle bracket (with gusset) through bolted to those returns, with the other leg of the angle attaching to the side wall of the pilothouse where I can get internal access to put a backing plate and again through bolt.
 
Brian

Sounds like a good design. Hadn't considered the option of bending the pole but that does give you more scope to come forward. I wanted the topping lift attached to the flybridge deck (not pilothouse side) so really couldn't easily come forward of the side door. You may recall on Poseidon the internal stairs to flybridge is a different location to yours so I think that side is not as structurally sound as for you.

I understand the conventional location (Beebe) is between 1/2 and 2/3 aft but speaking to the flopper stopper guy his recommendation (within those general parameters etc) was to position them around the middle of your engines location (essentially at the centre of mass in that area). Not sure if your re-power changed this for you but for my original cat 3208s this was also just aft of the side door.
 
My location is virtually midship, exactly the same location as my Naiad's. The latter are OK anywhere in the middle third of the boat, so they told me when installing. Yours might be better located but I think I'll be fine.
 
Insequent said:
Thanks Rich.

I am having a custom 8' pole fabricated as the Magma telescoping aluminium pole does not look all that suitable IMO. That work is in progress. What is suspended from the pole to do the work is yet to be finalised. Here is another local option that does work well, but they are a bit heavy and awkward to store when not in use, and they are also expensive.

https://www.boatstabilisersaustralia.com/products/flopper-stoppers-anti-boat-roll-device/

I will install two, one each side. It sounds like it was OK for you, but not great, when you used it. I am interested to know whether it sank quickly enough, and opened quickly enough on the upward movement.
Click to expand...

The Magma, and for that matter all of them, need added weight to pull them down quickly enough on the downward roll. I think I had about eight pounds of lead suspended below it. I liked how the unit stowed by folding up. Two should help you out of excessive rolling. As the the AL pole, it was in compression when the boat rolled upward meaning really heavy duty material for the pole was not needed. While I had a fiber topping lift to hold it in place in the vertical plane, I could see a tripod arrangement with the main pole at deck level and a couple of struts going down toward the water line to take the load on the up roll.
 
I have used the Magma Flopper Stoppers at anchor for many years on many different boats and they work really well. I have had no issues with them spinning and have not had to add any weight to them. One on each side of the boat (suspended from a boom) is best but I often just swing with deck crane off one side of the boat and clip the flopper right to the end of the crane cable. Its best for the flopper to be at least 6 feet submerged in the water. It slows and inhibits roll at anchor.
 
Rich, Taras

Good feedback, just what I was after, thanks. I'll go ahead with buying them when they come into stock here, and hopefully will have it operational in a few weeks. I'll post photos in due course.
 
Poles are the best way to use any roll reducing object. The further out from the side, the more leverage is applied against the roll.
On a pole, rigged correctly, flopper stoppers can be run at any speed, and greatly reduce the swells effect.
 
Magma Flopper Stoppers are completely silent in operation. As stated, the further outboard of the boat they are placed in the water, the bigger the leverage effect in stopping rolling at motion. Lastly, I keep mine about 6 feet below the surface of the water. Deeper=better.
 
Use Magma

We have a set of the Magma devices and deploy w/o a pole. They do ease the roll. After 3 years the spot weld on both devices failed allowing the hinges to fall away. I was able to purchase new hinges and, instead of welding I drilled a series of holes in the hinge and “wing” affixing with ss bolts, self-locking nuts and lock tight. Been back in use for 2 years now. Based on my experience I would suggest doing this nut and bolt addition immediately only because it is easier to complete with everything still attached in place.
 
I'm fairly happy with the Magma flopper stopper. One unit on the outrigger reduced my roll at anchor significantly. Without the outrigger the reduction is much less.

I had the same issue with the hinges as Chip. One of the spot welds on the hinges gave way so I drilled six holes and thru-bolted them. Should be good for a few more years when the rigging lines might need replacing.
 
Thanks for the tip on bolting the hinges guys! Neither of you mentioned adding extra weight to them so I will try them without any mods for a start.
 
Tidahapah said:
Brian,
I had the Magma flopper stoppers on Tidahapah.
I added some weight by welding a 1/2" s/s bar along the lower edge in the turn out (either side) and also a 1/4 " s/s round on the outside edge.
This did improve their performance. My main complaint was trying to stop them spinning.
On new boat going for a small set of the boat stabiliser australia round ones.
Click to expand...

Makes me wonder if a couple of appropriately sized rudder-like fins might reduce the spinning in current.
 
Better late than never.

Hoping I'm not too late to throw in my 2 cents.

I'm probably the only guy around with outriggers & floppers on a little 28' flybridge, but I hate it when my drinks are spilled.

I've been working for years with what I'll just call flopper-stoppers (but not necessarily that brand). Have used rotating ones, flapper types, cones, buckets & now Magmas. Learned a lot along the way.

For one, always use outriggers. No shorter than half your beam & up to 1-1/2x beam, but for that you'll need a high attachment point (mast). Shoot for 45-30 degrees (from hoiz.) at the flattest for the support cables or the stress can get pretty high.

Here's the thing about the "extra weight" and drop speed. You can add weight, but it's a pain to drag around and can bang things up and.. it's just undesirable. Thing is, the drop is not as big of an issue if you don't have it flying up and down a long ways. So, ALWAYS run with them on both sides. With only one side, it damps on the way up, but the boat rocks back down too fast & it can't drop fast enough. Next upswing. the line is slack so it accelerates up and jerks on it, and it just does't work. Just use 2.

Also, regarding pole length: I found a longer poles give better leverage & damping, but increase travel up and down. This contributes to the problem of not dropping fast enough to cover that distance. A shorter pole is nice because it reduces up and down travel distance, but has less leverage to damp the rolling. But, this can be overcome with larger flopper-stoppers. That has turned out to be the winning setup for me. My Magmas are rated for (I think) something like 30'-40' vessel or something, using one. NOT. I've got 2 on 4' SS poles on an 8' beam and it's rock solid. Since they get massive traction on the way up, they hardly travel any distance (maybe a foot). So dropping isn't an issue. In conditions that would normally launch pans off the stove, it doesn't even slide a wine glass on a smooth tabletop.
Absolutely love stabilizers. Don't leave home without 'em. You just have to get them dialed in for your boat.

As for twisting, always throw a swivel on top where the lines connect to the pole.
Hope some of this might be of help. Good luck!
 
Oh, never too late really.

My plan is for 8' poles and I have a 16' beam. I always intended to use 2. I doubt my angle will be 45°, but it should be above 30°.

Thanks for sharing your experience!
 
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