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Magma flopper-stopper WAS: roll reducing fins-a long post


Sven
 

Hi Peter,

As I said,  the units are of unknown age so I don't consider it a design flaw.  Both failed on the same place in the same way,  as shown in the picture below



I'd guess that the sharp bend in the line over the years has stressed the outside strands to the point where the violent forces on Sunday AM just ripped through them all.

I'll be replacing the lines with 3/16" 316 stainless.

What part of your system are you redesigning ?


-Sven


ALAN LAVINE seaVocean
 

I have these Flopper Stoppers for my Willard 810 cutter. I've had them for approximately 4 1/2 to 5 years and just recently replaced the lines with Wayne Imaging. I bought them used and they've had several years on it before I got them I believe it's the fact that the salt water stays in the line after it's been used and really doesn't get thoroughly flushed out that causes that wine to eventually deteriorate and part. Please provide pictures of your completed stainless steel restoration the bridal

On Aug 17, 2020 10:13 AM, Sven <southbound@...> wrote:
Hi Peter,

As I said,  the units are of unknown age so I don't consider it a design flaw.  Both failed on the same place in the same way,  as shown in the picture below



I'd guess that the sharp bend in the line over the years has stressed the outside strands to the point where the violent forces on Sunday AM just ripped through them all.

I'll be replacing the lines with 3/16" 316 stainless.

What part of your system are you redesigning ?


-Sven


Sean Eamon Kennedy
 

Just a thought, but you may want to keep the line as the weak link in the system. Better a section of the line parts than the arms get ripped off the boat. 

Might also do to add another, unstressed, recovery rope attached to the vanes. That way if something fails you can recover them.  


On Aug 17, 2020, at 10:13 AM, Sven <southbound@...> wrote:

Hi Peter,

As I said,  the units are of unknown age so I don't consider it a design flaw.  Both failed on the same place in the same way,  as shown in the picture below

<Screen Shot 2020-08-17 at 10.03.20 AM_easyHDR-default.jpg>


I'd guess that the sharp bend in the line over the years has stressed the outside strands to the point where the violent forces on Sunday AM just ripped through them all.

I'll be replacing the lines with 3/16" 316 stainless.

What part of your system are you redesigning ?


-Sven

--
Sean Eamon Kennedy
Vega Voyager “Moonlight”


Sven
 

Hi Sean,

When we re-did all the paravane cabling and beefed up the outriggers we first took out the 3-strand line from the tip of the outrigger down to just about 2' above the water and instead used 1/4" SS from the tip down to the fish & flopper-stopper attachment point 4-5' under the water surface.  As it turns out,  that made the cabling sing throughout the boat so we quickly spliced 3-strand line into the rig again for sound absorption.  That is now also our weak point and it should tear before any hardware gets torn off the boat.

We use a floating yellow retrieval live that we attach to both the fish under way and the flopper-stoppers at anchor.  There is no way I'd want to try to pull up the flopper-stoppers in a swell,  without an off-center retrieval line,  it is also the only safe way to haul in the fish.



-Sven


Peter P
 

Looks like there needed to be a thimble where the line meets the shackle. 

Right now, I have spinnaker poles that I believe are OEM. Challenge is they are heavily oxidized and their 4-inch diameter make them heavy. Recall, I am installing a hard top so the mast is now gone - I used to rig these with a single line up to the mast, then two lines down - one forward and one aft which was cumbersome. The hardtop frame is very sturdy so I plan to rig two 'up' lines and just one 'down' line, so setting should be a little easier as the two 'up' lines to the hard top frame will hold it in place fairly well. 

My sense is there is not a ton of pressure on the system. and the poles are 100% in compression so the 4-inch spinnaker poles are way over-kill. I am thinking of going with 1-1/2" stainless steel. McMaster Carr carries decent U-Joints that will enable the arms to be stored horizontally against the cabin sides, just as the old ones do. Scale will be a bit smaller though. Rough sketch below. 

I don't remember if my current arms are 12 or 14 feet. They seem long for simple flopper stoppers. I was thinking of reducing to 10-feet. Thoughts?

Peter







Peter P
 

One more thought on flopper stoppers Sven - I would think some shock absorbency via Nylon 3-Strand braid would be beneficial. Looks like your parted lines were spectra or something similar. And you're going with SS wire rope. What do you think of going with something with some modest stretch? 

Peter


Pease, Dan
 

That system on the Weebles? Pictured here seems a little forward of amidships.  Beebe called for them to be ⅔ of the way aft I think. Being aft makes tripping less likely underway.


On Mon, Aug 17, 2020, 15:40 Sven <southbound@...> wrote:
Hi Sean,

When we re-did all the paravane cabling and beefed up the outriggers we first took out the 3-strand line from the tip of the outrigger down to just about 2' above the water and instead used 1/4" SS from the tip down to the fish & flopper-stopper attachment point 4-5' under the water surface.  As it turns out,  that made the cabling sing throughout the boat so we quickly spliced 3-strand line into the rig again for sound absorption.  That is now also our weak point and it should tear before any hardware gets torn off the boat.

We use a floating yellow retrieval live that we attach to both the fish under way and the flopper-stoppers at anchor.  There is no way I'd want to try to pull up the flopper-stoppers in a swell,  without an off-center retrieval line,  it is also the only safe way to haul in the fish.



-Sven


Peter P
 

If I recall, Beebe was talking about paravanes for under-way stabilization. I have hydraulic stabilizers, so only need it for at-anchor. Much less stress on the rig so it can be much smaller and lighter weight. 

Peter


richarddalaska
 

Peter,

You are correct that your outrigger spinnaker pole is WAY overkill. I suggest you use aluminum rather than SS just for ease of handling . If the pole is heavy today it will be a lot heavier when you pass 75 years old. Use carbon fiber if the Dow hits 30,000!

For flopperstoppers it is absolutely essential to have some elasticity in the line I used to deploy mine with amsteel which is how my paravanes are rigged also. As you know Amsteel (and other dyneema lines) have almost no stretch. The first time we used the FS in a rolly anchorage my wife said it was the worst night sleep she ever tried to get. Whenever the magma vanes opened there was tremendous shock on the boat. Now we rig some springy shockles in the cord  and that problem is eliminated.

The magma FS are not the best since the boat has to roll about 5-10 degrees before the sides flop open. There is a better design: www.FlopStopper.com but they are even more costly than magma. 

I am hoping that my installation of the roll reducing fins will eliminate the most of the need for using the flopper stoppers.

When the magma FS are deployed there is supposed to be a retrieval/twist-reducer line attached to  the boat. So even if the crappy line that magma supplied breaks you won't loose the FS. 

As mentioned by Sven, some people attach retrieval line to paravanes. However at 6.5knots the drag on even a 3/16" line is substantial and causes the "fish" to position themselves even further aft than normal.  

I rigged a retrieval system for the paravanes that eliminates almost all muscle effort to get them out of the water and into their "holsters" on the stern. I did this only after I got a hernia when lifting them out of the water during the first year of use. Once I stop the boat it takes abut 3-4 minutes to retrieve the pair. I would try to describe the system but it would sound so much more complicated than it really is that no one would think to do it.

The only way to COMPLETELY eliminate rolling at anchor is to cruise in the PNW where there are 100s of real anchorages that have zero wave action. Of course it will be raining at anchor half the time but you won't be rolling. 

Richard P


Pease, Dan
 

Gotcha, very good point.  Easy tho from the photo to get the wrong impression.


On Mon, Aug 17, 2020, 16:34 Peter P via groups.io <pete_pisc=yahoo.com@groups.io> wrote:
If I recall, Beebe was talking about paravanes for under-way stabilization. I have hydraulic stabilizers, so only need it for at-anchor. Much less stress on the rig so it can be much smaller and lighter weight. 

Peter


Sven
 

Peter and Richard,

Our arch (replaces the mast) which takes up the F-S & fish forces flexes enough by itself to soften out any jerkiness.  In addition to that we have ~8' of the 1/2" 3-strand line going down to almost the water surface for additional cushioning.  There is zero noticeable jerkiness onboard,  none,  nada,  ingen :-)



We are still playing with the tie-offs to the aft guy-wire (actually line) and the retrieval line.  I've played with the idea of running the retrieval line forward when underway with the fish but haven't yet tried it.  As Richard points out,  the aft tie-off certainly must pull the fish further aft but I'm not sure it is a problem the way it is.

One advantage of bilge-keels (as opposed to an extended central keel) is that it would allow beaching in protected mudflats like those we keep seeing when looking at the Maine coast !  Still thinking about the possibilities.



-Sven


Bill
 

The BC Forest Service ran a fleet of boats on the entire coast of the province for decades. Most were round bottomed carvel planked boats, several were double-ended. Their hulls were much like our Willards, including a tendency to roll.

They standardized on a “bat wing” style stabilizer which consisted of a large flat steel plate bolted to the bottom of the keel with two vertical braces bolted to the hull sides, usually near or above the waterline. 

I was reminded of them by Sven’s comment about beaching on mud flats. This stabilizer allowed the boat to sit securely on any flat surface. I also assume that they provided a reasonable amount of stabilization, as the Forest Service were an experienced, long term user and builder of displacement boats in the 30 to 50 ft range, and adopted them broadly over bilge keels and paravanes which were also common.

I saw one of the boats decades after it retired and became a pleasure boat. It still had its “bat wings” in place, so I assume they were durable and enhanced pleasure use.

Photo below from internet, is not exactly the Forest Service design as the vertical plates don’t come up to the waterline, but you get the idea. 

Bill
--
W36S #34


Richard A. Miller
 

The line looks light to me.  I assume it is nylon?

Ever time the line comes under stress it stretches over the stainless eye, creating localised friction, heat, and wear.  The result is apparent in your photo.  

Same phenomenon in mooring pennants passing through/over fittings can cause a very heavy pennant to fail under the stress of wave-induced heaving.

Richard Miller, W40 FBS Adria

On Aug 17, 2020, at 12:14 PM, Sven <southbound@...> wrote:

Hi Peter,

As I said,  the units are of unknown age so I don't consider it a design flaw.  Both failed on the same place in the same way,  as shown in the picture below

<Screen Shot 2020-08-17 at 10.03.20 AM_easyHDR-default.jpg>


I'd guess that the sharp bend in the line over the years has stressed the outside strands to the point where the violent forces on Sunday AM just ripped through them all.

I'll be replacing the lines with 3/16" 316 stainless.

What part of your system are you redesigning ?


-Sven


richarddalaska
 

Form the naval architect's analysis that Luis Soltero had done for his fins, it is not the are of the fin that counts. Rather it is the turbulent drag that occurs at the shop edge. So one shouldn't be comparing area ion keel vs area of fin. Better perhaps to put a knife edge on the bottom of the keel.

The fins that I installed are too short (~12") to permit beaching the boat and, because they are thin, I would not want thousands of pounds of force on them if the boat was leaned over.

Richard P
--