Catalina 250 WB swinging on a mooring buoy

[sebastko]

Hello,
I'm a new boat owner. I've seen my Catalina 250 (water ballast version) doing this funny dance, swinging from side to side like pendulum for the past few hours - see the video below. The camera is facing west, the wind is light 2-3 knots coming south-west... the tide is rising, so I think the current should be flooding towards the camera, so should be matching the wind... The centerboard is up (to be prepared for low tide) and the rudder is taken off (incidentally I've been doing some maintenance on it). There's one keel sailboat and one small power boat moored nearby and they stay still.

I saw some threads about boats swinging/sailing at anchor. The advice is often to add an anchor sail at stern. I just wanted to confirm if this situation looks "normal" to you, more experienced sailors and boat owners, and whether this standard advice still applies. Also, do you think having the centerboard up or the rudder out may have affected it? Are there any negative effects of such swinging? I imagine some shockwaves must be going through the whole boat every time it pulls on the mooring line? Maybe this is why my steering system broke a few weeks ago?

Is there anything else, other than adding an anchor sail, I should be doing to prevent it?

PS. Sorry about the fenders, I've been worried about driftwood hitting my boat

 

[justsomeguy]

add an anchor sail at stern.

Yah, try that.

 

[mdidomenico]

when i had my '96 250wb it did the same thing at anchor. it was chalked up to being a little light when sitting in the water and the boat not having any real appendages under the water to keep it going straight. the two things that helped the most were having an additional offset line (ie instead having just the anchor line) so the boat basically pulls to one direction constantly as well as having a riding sail. turning the rudder hard over also helped, but since your's is missing thats most likely why the movement is so pronounced

 

[jssailem]

Welcome to the SBO forum.

Your bio says you are on a mooring ball up in Port Susan. Where the water can get skinny ( why you raised the center board), the winds can swirl (west wind blowing over Camino Island and down into the bay - or up from the the south east with 10 miles of open water fetch ). You tie your beautiful light on her hull, no center board, sail on the boom, sail on the furler, little or no ballast, (like a young colt with lot of energy) to a mooring. Of course she’s going to skitter about trying to break free. And she will as the skittering about is going to chafe through the bow lines.

She is dancing on the surface with nothing in the water so slow her down.

You can try the center board. Perhaps a little ballast. Removing the mainsail will give her a little less windage. Adding an anchor to the stern will definitely stop the dancing but she will still strain on her tethers do add chafe guard to all your mooring lines. If you don’t have a second anchor an unbaited commercial crab pot could suffice to slow her movements.

I would definitely check on her before any strong storm fronts roll in.

 

[Kings Gambit]

That’s a pretty dramatic amount of swinging. ‘Bout the only remedy that could really stop that would be a stern anchor. Otherwise, perhaps rig a modified Pardey (winch) bridle which is used to fix the boat’s bow about 30 deg off the wind by winching a line leading from the cockpit winch to the anchor rode positioned maybe 15 ft from the bow roller. (However, this might not be feasible if attached directly to a mooring pennet.) The wind pressure on the boat at that angle should keep it from “sailing.”

 

[jssailem]

The wind pressure on the boat at that angle should keep it from “sailing.”

I agree with this observation. Your challenge is two fold. The tidal currents will at times try to work in contrary direction to the wind. The boat being light on the water will rotate to adjust to the wind.

If you use this option, I would set it up and then spend time on the boat to see how the boat will react to varying conditions.

 

[Davidasailor26]

Looking at the video there’s a very distinct change in water surface running from bottom left to top right, right across the mooring. That could be some kind of transition of the current, which could be contributing to the swing. If the current is in play then adding more surface area under the water might change the motion, but not necessarily fix it. That would also explain why the other boat, on this side of the transition area, doesn’t have that much swing. I think it will just be a matter of experimentation to find the right combination of windage and wetted surface. If another mooring location away from that transition zone is available that might help too.

I imagine some shockwaves must be going through the whole boat every time it pulls on the mooring line? Maybe this is why my steering system broke a few weeks ago?

While the swinging is quite violent, it’s probably no worse than actually sailing in waves. So if that was enough to break the steering system it was probably just a good indicator of other trouble.

 

[sebastko]

Thank you very much for detailed responses and lots of great advice!

Just wanted to clarify: the boat is not swinging like this all the time - in fact, this was the most pronounced movement I've seen so far. I think Davidasailor26 is right it was some unusual transition of current. But it does swing quite often, so I'm glad I posted that video to get some feedback.

To sum up some take-aways from this thread so far:

• Add a riding sail, maybe an anchor at stern
• Turn rudder hard over
• Keep the bow at an angle by using an additional line (I think both mdidomenico and Kings Gambit gave different versions of this advice)
• Use chafe guards (thanks for pointing this out, jssailem, I haven't thought about that problem!)

And yeah, I agree, Davidasailor26 - I'm probably lucky the steering system broke while moored and not while sailing in challenging weather!

 

[Kings Gambit]

A riding sail is more trouble to get fitted and will probably prove less effective than routine use of a stern anchor, and might be a bit noisy. The boat will still yaw some with the r-sail but not with the stern anchor. Each in fact offers a different solution to different versions of the problem. If being anchored for long (say overnight) you’ll be happier with the anchor. In months of nights spent at anchor I’ve seen many boats anchored bow and stern but cannot recall seeing even one sloop using a special-made riding sail. This would not include ketches and yawls which have a small sail aft that works as a riding sail is supposed to, but on sloops they are an “add-on.” I recall some years ago asking my sailmaker at the local loft if I should have a riding sail made for my sloop to address the problem you and others have experienced. His response was: “Do you have everything else you need for the boat?” I did not get one!