Anchor riding sail for catamarans?

[Nahbrown]

Any recommendations?

We are in a good blow (28mph) right now in the Exumas and our swinging back and forth on the anchor has me contemplating an anchor riding sail.

Ive seen them on plenty of monohulls but I have yet to see one on a catamaran.


Anyone using one? If so, a link to the sail would be appreciated!


Thanks!

[boatman61]

Strange.. never had this problem on a cat with a decent bridle set up..

[Nahbrown]

Originally Posted by boatman61

Strange.. never had this problem on a cat with a decent bridle set up..

Really? I see two leopard 45s, a Catana, HH50, our L440 a leopard 42 and two other cats in Blackpoint Settlement for this blow and we are all swinging. Not nearly as bad as the monohulls are swinging though.


The Catamarans I listed have varied set ups, the Leopard 45s have a Y shaped bridle and ours and the HH 50 have a longer V set up. (I hope that makes sense)

[Mr B]

I anchor off the centre cleat on my Cat, My Cat goes around in circles all night long,
Basically the same as a bridle off both bow cleats,
Occasionally it accelerates forwards till the anchor stops it, Clunk again,
I tried a stern anchor but it gets caught on the rudders, So I stopped using it,
Tied to a pier, Its racing backwards and forwards all night,
It slowly moves away from the pier, Then accelerates till the rear mooring ropes stop it dead in its tracks, With a bang,
I have tried various positions with the rudders, But that does nothing,
The one that really gets me, Is my stern likes to point into the wind,

[UFO]

Originally Posted by Nahbrown

Any recommendations?

We are in a good blow (28mph) right now in the Exumas and our swinging back and forth on the anchor has me contemplating an anchor riding sail.

Ive seen them on plenty of monohulls but I have yet to see one on a catamaran.


Anyone using one? If so, a link to the sail would be appreciated!


Thanks!

Never moved around enough at anchor on my 440 for it to be a problem - Bridle is 7M long per leg.


What size chain do you have? I have 1/2 inch, which albeit well oversized gives a certain stability to the boat at anchor.


Do you have a hard top on the fly bridge or any other mods that could increase this swinging?

[smj]

Try letting out more scope on your bridle, you may not sit dead in the wind but shouldn’t sway much either way......unless there’s some current coming in to play.

[Tin Tin]

It is probably because the wind is swirling bullets in that harbor rather than the boat "sailing" off the anchor. Watch the wind indicator, see if it swinging a lot. Also tie a ribbon down low, the wind at the top of the mast could be a lot different to sea level especially in Bahamas with very low lying land mass.

[Dave_S]

Sorry for the dumb question, what is an anchor riding sail ?

and why do I feel like I'm going to regret the question ��

[Nahbrown]

Originally Posted by Dave_S

Sorry for the dumb question, what is an anchor riding sail ?

and why do I feel like I'm going to regret the question ��

https://www.sail-world.com/Australia...rce=duckduckgo

[fxykty]

Originally Posted by Nahbrown

Really? I see two leopard 45s, a Catana, HH50, our L440 a leopard 42 and two other cats in Blackpoint Settlement for this blow and we are all swinging. Not nearly as bad as the monohulls are swinging though.





The Catamarans I listed have varied set ups, the Leopard 45s have a Y shaped bridle and ours and the HH 50 have a longer V set up. (I hope that makes sense)

How long is each leg of your V? My first thought is that they’re too short, but if 6m or more per leg then you should be fine. That’s only 14 knots, which is not that much. In steady winds with a decent V bridle from either bow you shouldn’t have any swinging troubles.

In stronger winds, especially gusty, there is going to be surges and swinging as the chain gets lifted, you get pushed back, then the wind drops and you surge forward, then the next gust catches you with slack bridle and rode and you swing sideways as you get pushed back. It’s a pain, but not much you can do.

Most cats have plenty of windage aft with davits, panels and bimini. But if you have a cat with small trampolines and lots of cabin then you may not have enough windage far enough aft. You could try a small double sail between the end of your boom and both sterns.

[NevilleCat]

What about trying shortening one leg of the bridle?
Easy to try, it might sail out to one side and settle down.

[tamicatana]

—Each leg of the bridle should equal your beam
—Mount as far forward on the bows as possible
My boat never, ever swings as much as the monohulls do.

It was our experience that in the Bahamas, current and swell had varied effects. We sometimes had to rig a swell bridle, which in our case meant taking one leg of the bridle, making a line to it, and making it fast to an aft cleat such that the bows faced the swells’ angle (the aft was our adjustment point).

https://www.jmpeltier.com/sleep-tight-swell-bridle/

[chris mac]

We are over in eleuthera, pretty much same winds. We barely swing, but have 20 feet on each bridle leg.
Last year I helped a friend on a leopard 38 who did sail at anchor. They did have an anchor sail, and it did help. But it was a pain to set up. So he made up a new bridle, similar length to mine, and it settled them right down.
Tomorrow we are heading back to the exumas for a couple weeks. Maybe I'll see you over there.

[Palarran]

I deviate quite a bit with conventional wisdom on this, but I'd shorten scope. In the Bahamas you are probably in 15' of water max over a perfect sand bottom. It's really easy to let out 7-1 scope, and some go to 10-1 because it's windy. This allows the boat to ride up when there is a lull, it falls off to one side, then takes off. I've found that 4 - 1 or 5-1 is way better to keep the boat centered and not hunt at anchor. Many, many times we have anchored in the Exumas where our anchor was one boat length in front of us. Of course you need a properly sized anchor for this though.

[thinwater]

A bridle is nearly always all the solution that is required. A riding sail can help, but most cats already have a big hard top with a lot of windage aft. But there are lost more answers:

• Two anchors in a 100-130 degree V. No fore aft, but wide enough that they don't reset in a reversal. To avoid tangling, terminate the secondary rode to the main rode forward of the bridle apex (or at the apex--I made a special plate for this).
• Drogue from the apex. Slows yawing and surging. Just enough rope to keep it in the water.
• If you can raise the rudders (Gemini) raise them. Keep the boards down. If you raise the boards and keep the rudders down you ARE going to sail at anchor. No help for you.
• Hammer lock. Lower a second anchor or kellet until it just scrapes on the bottom (1.5:1 scope). Very effective, but do not use if there is sea grass or coral.
• Riding sail. If you must. The simplest AND most effective is a diamond of cloth rigged over aft 2/3 of the boom and sheeted outboard in a wide V, and then the boom is raised. 3-5 feet. Very strong, very effective. Single luff (traditional) riding sails don't work on multies.

Good luck.