Sailing at Anchor

[Dave_S]

Originally Posted by thinwater

Lift the rudder and keel. No more yawing, no more trouble with tides.


Not an answer for cruising boats, but very effective for trimarans.


I'm anxious to hear if he tries a hammerlock mooring.

Originally Posted by 44'cruisingcat

Works for us too.

I have a similar problem, my boat is almost never doing what the other boats are doing and it is a PITA. On a mooring I end up with huge knots that take a swim and 20 minutes to undo + cut up hands (Cid harbour comes to mind). I end up shortening my bridle until the mooring buoy is up out of the water.

I was thinking of the bucket out the back, it might not be big enough.

I put the boards all the way down but this only works sometimes.

Your saying if I lift the boards and my rudders it will set to the breeze and have no lift under the water to sail up on. I still wont be doing what the other boats do but it stops sailing up on the anchor?

[thinwater]

Originally Posted by Dave_S

Your saying if I lift the boards and my rudders it will set to the breeze and have no lift under the water to sail up on. I still wont be doing what the other boats do but it stops sailing up on the anchor?

Not 100%, but it should help. The rudder is the important part (boards up, rudder down will make yawing worse).


Also useful in gusty oscillating conditions; the boat can move sideways more easily.

[Rex Delay]

I do not understand the physics involved but some boats "sail" at anchor, some do not. From personal experience a Hunter 41 sails uncomfortably at anchor, a C&C 41 does not. A Hanse 40 was absolutely miserable in a blow on a mooring where a Sceptre 36 was rock steady into the wind. Cannot explain why.

[44'cruisingcat]

Originally Posted by Dave_S

I have a similar problem, my boat is almost never doing what the other boats are doing and it is a PITA. On a mooring I end up with huge knots that take a swim and 20 minutes to undo + cut up hands (Cid harbour comes to mind). I end up shortening my bridle until the mooring buoy is up out of the water.

I was thinking of the bucket out the back, it might not be big enough.

I put the boards all the way down but this only works sometimes.

Your saying if I lift the boards and my rudders it will set to the breeze and have no lift under the water to sail up on. I still wont be doing what the other boats do but it stops sailing up on the anchor?

There's a mooring in Cid?

Anyway, we lift the rudders and pretty much point at the wind. Certainly would in somewhere like Cid, where there's not much tide.

Places where there's not much wind but lots of tide, might be better with rudders down.

[thomm225]

Originally Posted by thinwater

Lift the rudder and keel. No more yawing, no more trouble with tides.

Yeah, on a catamaran where you can raise your boards and pop up your rudders it's quite easy to make the boat point where you want it.

When coming off the beach on beach cats in 15 plus knot winds blowing offshore, we experienced sailors just sat on a hull with feet in the water drinking a prerace beer all "boards" up and backed off with the main sail sheeted in near center and jib flapping while newbies tried to sail off the beach sometimes pitchpoling

[Eder]

On my IP had this problem when anchored at Isla Espiritu Santo. A fellow sailor showed me how to put out the rode...install snubber...then add slack rode behind the snubber till the loop of chain hanging off the snubber drags on the bottom... settled my boat down substantially.

[thinwater]

Originally Posted by 44'cruisingcat

...Places where there's not much wind but lots of tide, might be better with rudders down.

Could you explain your reasoning? Lifting the rudders makes the CLR move forward, which results in the windage COE being aft of the CLR, which is stable. But that is wind-only.


Why would lowering the rudders help when there is tide? I'm not visualizing this.

[a64pilot]

Originally Posted by Shrew

Is your rudder hard over?

It seems that rudder has no effect.
My boat is sailing, from airflow on the hull. Not from the waterflow on the keel, although in heavier current I can see that too.
I theorize that although she is sailing, speed through the water is so slow the rudder has no effectiveness.

[a64pilot]

Originally Posted by Ecos

I was thinking of a64, if he uses a long snubber. Chain all the way up to the boat would have more drag on the bottom and the boat would gain momentum more slowly and never fly fwd maybe.

All chain or long snubbed seems to make no difference.
I have recently gone to a long, thin snubber after conversations with Nolex. I have about a 40’ piece of I think 9/16’ line and bring it back to the midships clear and attach it to the chain just shy of the waterline, this leaves it long enough to be stretchy, but keeps it out of the water.

[contrail]

Originally Posted by Eder

On my IP had this problem when anchored at Isla Espiritu Santo. A fellow sailor showed me how to put out the rode...install snubber...then add slack rode behind the snubber till the loop of chain hanging off the snubber drags on the bottom... settled my boat down substantially.

I do the same. Sometimes there is quite a pile of chain down there!

[a64pilot]

I really don’t want to drag all that chain through the mud, but as may give that a try, it’s really only a problem in higher winds like today, gusting to 25 kts.

[44'cruisingcat]

Originally Posted by thinwater

Could you explain your reasoning? Lifting the rudders makes the CLR move forward, which results in the windage COE being aft of the CLR, which is stable. But that is wind-only.


Why would lowering the rudders help when there is tide? I'm not visualizing this.

Light wind, strong tide, rudders down makes the boat hang with the tide rather than the wind.

More wind, and rudders up is preferable.

[Dave_S]

Originally Posted by 44'cruisingcat

There's a mooring in Cid?

Anyway, we lift the rudders and pretty much point at the wind. Certainly would in somewhere like Cid, where there's not much tide.

Places where there's not much wind but lots of tide, might be better with rudders down.

No sorry the mooring I was thinking of is at Moreton.

The Cid harbour reference was because I was in the water with bleeding hands thinking about sharks.

[Pauls]

The physics of sailing at anchor are simple. You have 2 factors:
1. The wind pressure on the above water part of the boat, which will have a center of pressure point.
2. The water resistance on the below the surface part of the hull, which will also have a center of pressure point.

If the center of wind pressure is aft of the center of water resistance the boat will be naturally stable at anchor. A schooner with its center of wind pressure area well aft is a good example.

If the center of wind pressure is forward of the center of water pressure the boat will be inherently unstable at anchor. This describes the typical sloop.

A riding sail is a way to move the center of wind pressure aft.

If you have a bowsprit, anchoring off the sprit by running your spring line thru a block at the end of the sprit can help a lot. It doesn't change the relationship between the wind and water pressure centers but it increases the leverage of the anchor line tension on the hulls pointing direction. It's pretty effective.

[thinwater]

Originally Posted by 44'cruisingcat

Light wind, strong tide, rudders down makes the boat hang with the tide rather than the wind.

More wind, and rudders up is preferable.

Makes sense. That is what I have observed. Complicated.