"Sailing" at mooring

[captjj]

I have a Bruce Roberts designed 43ft ketch that wants to sail bare-poled while on the mooring bouy. With the wind up and an adverse tide she'll actually sail around the mooring ball occationally. Is this a design flaw or is there something I could do to correct it. The boat has a keel hung rudder and the keel is full with a cutaway forefoot. Could it be a ballast/trim issue or perhaps mast rake? Everything appears to be as it should be ie. masts parallel, floating on her lines etc. Thanks for any ideas. JJ

[ChristopherMoon]

All boats sail on anchor and moored...thats why you shave aboard then enter washrooms? Otherwise trying to shave in public the counter and mirror appears to move!...and you look impaired...smile and say yep..slept aboard! I have an older yawl and a great thing is to sheet the mizzen in hard and it responds like a weathervane..always points into the wind ends the nasty habit of staggering around a fixed point! Sloops and cutters etc. set a scrap of heavy cloth to a backstay and it will get the same results..even better you look like someone who cares about your vessel and others..cheers!

[TeddyDiver]

It's a matter of the aerodynamic form of the bow & mast fore.. so set the bouy from the stern and relax..

[tom28571]

Yep, It can be a trial to stop sailing on anchor or mooring. If it is going to be a problem in close anchorages, I put a line on a rolling hitch about 15 feet from the bow and secure to a sheet winch or cleat and pull the boat a bit off angle to the anchor. Then the boat can only hang to one side. It does put more load on the anchor though and that might be an issue sometimes. Two anchors at about 45 degrees off the bow restricts sailing also. Anchoring by the stern works also but few would go off and leave their boat that way.

The problem is usually due to the offset between the mast/rigging CE and the keel/Rudder CLR and affects almost all boats to some degree. That is, the windage at anchor is forward of the CLR by a considerable amount so the boat blows sideways, which the anchor rode turns into a sail to one side and then the other. When the rode pull exceeds the windage force, the boat turns back and sails the other way. It's a pendulum.

Just about the only thing that works on the boat itself is a riding sail as already mentioned.

[bntii]

Originally Posted by TeddyDiver

It's a matter of the aerodynamic form of the bow & mast fore.. so set the bouy from the stern and relax..

100% agree- tie off to the stern.

[Tcubed]

Tom beat me to it.

However i would add that in fact it is quite interesting to note the particularities of each design in this regard.
One design which is unusual in that it remains almost completely still on just one anchor is the Puerto Rican native sloops. (this is in a no current situation)
I used to own one and its dimensions were as follows; 24' x 8' x 4' . Mast 45', boom 30'. Mast is stepped about 8 foot aft of stemhead and raked aft such that the truck is right over the midships. This one was a bit shallower than some of the others , 5 foot draft for this length would be a bit more typical.
Notice that with the mast's rake and 14 foot of boom overhanging the stern it would not sail on the anchor one bit, just like its sisters.

Now in a wind/tide situation it gets much more complex, and can be a real nightmare as heavy, full keel, low windage boats will be much more influenced by the current than light high windage fin keelers. Thus they all end up doing different things and avoiding at anchor collisions can become quite unnerving. In this case a good solution is having an anchor upstream and another downstream.

[BHOFM]

I had a Catalina 25 on a mooring and when we spent the night it drove
us nuts. I had a 3' mooring line and shortened it to 18" and never noticed
it again.

The cable was fairly tight because we didn't have to deal with tides.

[Brent Swain]

Moor from the stern. She will lay there like a dead duck, in the strongest winds.
This , however, only works where there are no tidal streams or currents .
A small drogue off the stern sometimes works.

[HJS]

Sailing at mooring is because the aerodynamic center of effort is in front of the hydrodynamic center center of effort.

hjs

[bntii]

Mooring/anchoring:

http://www.jordanseriesdrogue.com/D_14.htm

[MikeC]

Try springing your bow line off to one side or the other. Sometimes this minimizes the "sailing" because the hull stays aerodynamically lifting on one tack and doesn't tend to come around on the other. This will cause more windage loading to mooring or anchor so be careful, but so will stern to mooring.

[gonzo]

On a sloop you can make a tiny sail that hanks to the backstay. It will create enough drag to keep the boat form sailing so much.

[Hunter25]

Increase windage astern so she'll head up

[MikeJohns]

As gonzo and Hunter just said.

I somtimes set the storm jib on the backstay with the clew sheeted fwd.
Other cruisers have a ciustom made small heavy cavas riding sail. On a ketch you can fly the riding sail on a 2nd track from th emizzen otherwise put up the first section of the mizzen down to the top reef.

[captjj]

Thanks for all of the good input. Because of the tidal current, I'm going to try setting a reefed mizzen and remove the roller furling jib the next time we have a forcast for strong winds.