"Sailing" at anchor

New to trawling, chartered an AT34 for a few days. Even in mild conditions, this boat "sailed" at anchor, tacking left and right about 40 degrees or through 80-90 degrees total. I come from sailboats, many of which do this as well. Do most trawler type yachts do this, and is there a solution? On the sailboat we kept the mizzen hoisted, strapped to center line and it eliminates this behavior completely.

In mild conditions this is a small annoyance (wife was trying to paint, and the view kept changing). If it does that in stronger weather it can be a hazard.

Were you using a bridle when you were anchored ?

No bridle. Just a snubber hooked to the chain, coming through the roller to the bollard. Does a bridle improve things measurably? On that boat the bow cleats are set outboard a bit, so they could have been used for a bridle.

We tried a bridle, still sailed around with one loose side and one tight, switch sides and go again.
Have seen many boats anchor with them with same results.

Went back to single large snubber and don't worry about it.
Just allow space when anchoring.

I thought maybe you were tied to an off center cleat, as that can magnify the sailing issue.

You could also use two anchors. I've used a bow and stern anchor, and have seen others use two off the bow ( at "10 o'clock and 2 o'clock )

More scope, using chain, can help a lot. Another technique that can eliminate tacking is to anchor as usual, then lower a second, small anchor off the bow straight to the bottom. Then pay out a bit more rode to the bower.

A small stern anchor can be used, of course.

Finally, if the boat has a mast & boom, a typical trawler "steadying sail" can reduce the problem a great deal. It varies by boat and experimentation is called for. Even if the usual steadying sail is unavailable, a small riding sail flown from the topping lift can solve the problem. This is but a tiny scrap of sail.

@MurrayM posted a pic a couple of years ago of an improvised riding sail that did a great job in a very windy anchorage.

In my experience, wind/current will blow most boats the same direction, so it isn't usually a problem, even when moored in a crowded mooring field. But I have seen one boat that consistently moves differently than the rest of the field. I suspect that either his rudders or stabilizer fins are not centered, but he says otherwise.

In each case we had all chain out and plenty of it. It wasn't pulling the chain around that much, more hunting the bow left and right. I'd not be that concerned about knocking rails with the neighbor, although in a crowded anchorage that might be a problem. More worried that in a lot of wind, this might continue or get worse, and it is possible to upset the anchor that way.

The boat didn't have an obvious way to set a riding sail. I'll try the bridle next time. Two anchors is a PITA, uses up space, and causes trouble at the tide/wind shift, so I leave that for more extreme circumstances.

Simi 60 said:

We tried a bridle, still sailed around with one loose side and one tight, switch sides and go again.
Have seen many boats anchor with them with same results.

Went back to single large snubber and don't worry about it.
Just allow space when anchoring.

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I think it depends on the boat. With a single snubber we sail around. Using a bridle, we still sail but no where near what we did with a single snubber.

Sabre602 said:

...
@MurrayM posted a pic a couple of years ago of an improvised riding sail that did a great job in a very windy anchorage.

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Yup, that little bit of tarp made a huge difference. Took our swings from about 40 degrees to about 15 degrees, which all but eliminated the down wind romp & subsequent bounce on the rode.

Often it does not need an actual sail to achieve it, but effectively you are trying to make the boat behave more like an arrow, by moving the windage aft. Our boat used to sail about a bit at anchor also, because the windage was more for'd, until the serendipitous (arrow fletching) effect obtained by replacing and extending the cockpit canopy, and adding in side deck covering, added to by the wind generator and pole, achieved this desired effect. Now, no sailing at anchor. See avatar pic. I suppose when the dinghy is up it helps catch wind as well.

My boat sails at anchor regardless of single or double line snubber. I use a 30 pound scuba weight belt on the end of a 1/2" line off a bow cleat with maybe 5' more than the depth of water. Doesn't stop the sailing, but probably reduces it by 75%. It drags easily enough that it doesn't inhibit the boat from reversing with the change of tide or wind direction.

Ted

Never been an issue on my boat. Perhaps a low profile, all-chain rode, and a keel helps. Here, usually tidal currents rule over the wind (but unlikely here pictured on flooded Mildred Island).

But, you have it on a bridle there?

The amount of sailing probably depends to a large extent on the house. The Coot has it's house set a bit further back, and yours has all the windage of the rig too.

O C Diver said:

My boat sails at anchor regardless of single or double line snubber. I use a 30 pound scuba weight belt on the end of a 1/2" line off a bow cleat with maybe 5' more than the depth of water. Doesn't stop the sailing, but probably reduces it by 75%. It drags easily enough that it doesn't inhibit the boat from reversing with the change of tide or wind direction.

Ted

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That’s an interesting idea. So it drags along the bottom I guess when when the swinging force overtakes the holding power of the weight? Does the belt ever get hung up on anything?

I wonder if hanging a 5 gallon bucket off your stern would act like a drogue and reduce the movement.

In the past, I have also brought just one leg of the bridle back further on one side to present a bit of "sail" to the wind. If you have a strong attachment point 1/3 or 1/2 back, it can help depending on the wave action.

We found that changing from a single part snubber to a bridle has almost eliminated the swinging. Our boat has relatively low profile with our center of windage further aft than many trawlers so the movement at anchor was not all that great. The bridle did make quite a difference though. Our bridle has one long leg which allows us to adjust the bridle, pull the anchor hook off center to counter some wave action too.

MYTraveler said:

In my experience, wind/current will blow most boats the same direction, so it isn't usually a problem, even when moored in a crowded mooring field.

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Not always. Different boats swing differently to different combinations of wind and current. Sail and power boats especially swing differently. And if two similar boats are side-by-side in a crowded mooring field, and "tacking" back and forth in the wind, they'll sometimes meet up when on opposite "tacks."

MYTraveler said:

In my experience, wind/current will blow most boats the same direction, so it isn't usually a problem, even when moored in a crowded mooring field. But I have seen one boat that consistently moves differently than the rest of the field. I suspect that either his rudders or stabilizer fins are not centered, but he says otherwise.

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It gets very "interesting" in SC and GA with strong currents. in Fernandina and St. Aug we've seen boats at 180 degrees to each other. Same in anchorages like Steamboat, Duplin and Cumberland Island.

Springing the rode is an old solution. Adding windage aft also works

Mine tacks like crazy. Light boat with a good amount of windage compared to what is under water. A true down side, but it is FAST!!

A few times I put a monkey line from anchor line to a side cleat. That helped, but was a PITA. Now I just ignore the "swimming".

I've thought of the bucket idea but given the size and the fact that it already has a keel, seems like a 5 gal bucket would do little. I wonder if a 10' diameter drogue would do something though.

In at at least some anchorages, dragging something from the bow has the opportunity to collect some junk off the bottom.

I like the changing scenery.

I believe that all boats do this to a degree. I believe it is simply physics. Look at a flag in the breeze/wind. It 'flaps' back and forth. It doesn't sit static. The boat is just doing a very slow, version of this.

Take a look at time-lapsed film of boats in a mooring field or on anchor. They all do it.

cardude01 said:

That’s an interesting idea. So it drags along the bottom I guess when when the swinging force overtakes the holding power of the weight? Does the belt ever get hung up on anything?

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The boat starts to drag the weight and then the stern overtakes the bow ending the swing in that direction. While the belt is a loop, it lays flat on itself and hasn't snagged anything, so far.

Ted

Cool. I like it.

We call that "The Anchor Dance"!

https://youtu.be/-A83t6VCV-0

When mine sails it enough to become bothersome I toss a 16 lb anchor on nylon rode off the stern, tie it off tight and that settles things down , I usually anchor in about 20' of water ot less.

boathealer said:

In the past, I have also brought just one leg of the bridle back further on one side to present a bit of "sail" to the wind. If you have a strong attachment point 1/3 or 1/2 back, it can help depending on the wave action.

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Agree, but it all depends on the boat and conditions. Worthwhile fiddling with the bridle, however.