Flopper Stoppers

[MoonDust]

Can anyone help with some advice on the design of a 'flopper stopper' to stop excess roll at anchor?

I read somewhere that you need a triangular board with a weight at one corner, suspended by a three-rope bridle (one strand attached at each corner).

However, field trials indicate that in this configuration the board simply floats vertically, which is no good at all. Do I need a weight at each corner with one weight slightly heavier than the other two?

Thanks in advance.

 

[Robin2]

The answer is "catamaran"

 

[WayneS]

It should be weighted on one corner only. If it just floats horiz then the weight is prob to little.

I rather use a bucket that is suspended so that the top is just below the surface when the boat is level. The bucket that I use has a weight on one side to help with filling but this should not be necc.

Cheers

Wayne

 

[Gazza]

Try Eric Hiscock's "Cruising under Sail". He describes the device and there is also a 'photo using rocks as weights.

 

[Mirelle]

Reduce the weight somewhat, or enlarge the triangle, and I fancy the weight is better on one side than at one corner.

 

[ronniewood]

Noticed an article a few weeks ago in one of the Mags about a device recently put on the market that has a number of discs on a line. Seemed to be very effective.
Sorry but cannot recollect which Mag.

 

[Gunfleet]

You can buy them from West Marine

 

[oldsaltoz]

G’day MoonDust and welcome to the YBW forums.
I have no experience with ‘flopper stoppers’ but I thing the physics would be pretty straightforward.
You need to have enough weight to sink the board. The weight should be fixed to a corner so that the full width of the board is exposed to the current during the upward movement.
You can increase the effectiveness by getting the rig as far outboard as possible, say on the end of a pole, and fit one to each side.

Andavagoodnightatanchour Old Salt Oz……

 

[Oldhand]

What happened to the small sail mounted aft on Drifters of old, wouldn't air damping from such top hamper help?

 

[Piers]

A USA mag, Passage Maker (http://www.trawlertravel.com/cgi-bin/site.cgi?) deals with trawler yachts, only. Stabilisation on these boats is always a factor, hence Flopper Stoppers feature fairly frequently, and almost every issue has comment / letters on them.

It seems the sizing is quite critical, not the least that they can so effective they can capsize a boat - although I doubt at anchor unless the sea is suffering from PMT.

Try a search on their site and see what comes up. Also, send an enquiry to the editor, Bill Parlatore. He's always keen to help.

Piers du Pré
MBM Cruising Club enthusiast
www.dupre.co.uk/fsPlaydeau.htm