Bad anchoring

[capn_billl]

I had a bad anchoring experience last week at a familiar anchorage I've used repeatedly.

It is a channel that runs North South fairly narrow, and shallow, but leaves 2 feet of water under my keel even at low tide.

It does have significant current at the tide change as it drains a very large swamp (lake?) in the Everglades.

Surrounded by mangroves it is usually quiet, and protected from all but a strong due North wind.

Guess what? That is what I got.

No problem, the tide was going out (to the South), and the wind while blowing with the tide wasn't excessive (20 knots).

Everything was smooth, until the tide change at 6PM right after sundown.

When as expected the current changed direction, to straight against the wind forcing my boat to do a 180. Still no problem, as I had anticipated that, and left plenty of swing room, and extra scope, and fetch to allow for pulling the anchor, and resetting, which it did successfully, (old style plow, sandy bottom, some weed, and mud).

Then came a wild bumpy ride.

The wind pushed me upstream to the limit of the anchor rode, apparently my Catamaran has more windage than water resistance because 20 knots of wind exceeded the 5-6 knots of current.

When I came to the end of the rode, I did a violent 180, then slowly went back down stream until again, a 180, then stop.

Sometimes the boat sailed right over the anchor chain, scraping the hull, then coming to a stop with the chain directly behind the boat. (hung up on keel).

When the boat swung sideways the current exceeded the wind force, and I went down stream, jerking to a stop aligned with the current, then with the keel aligned with the current the wind force pushed me back downwind.

I went back, and forth over the anchor at least a dozen times.

Turning the rudder to try to strike a balance just made the boat spin in circles.

It did this for 6 hours in spite of my best efforts to settle things down, then the tide changed, and by the next tide the wind had shifted 45 degrees, and just swung me gently at an angle.

I thought of launching the dinghy, and rigging a stern anchor, but I've never needed one before, and it was getting dark, and rough, and getting swept out to sea in a dinghy wasn't a good thought.

(maybe rig a halyard to the dinghy nose, and having my wife let me out slowly would have worked.)

If I had a small drogue, I would have used it to insure the current exceeded the wind.

Note to self, buy a drogue, and don't use that anchorage in a strong North wind.

[JPA Cate]

Yes, the drogue will help you lie with the current. Had a friend we met in Mexico with a trimaran who did exactly that to help him lie with the monos which at that time and place were the predominant numbers of anchor outs. It was quite successful. You're on the right track.

I'm sure that wasn't fun: you always wonder if your chain might snag your anchor and pull it out when you get to the end of the rode. You done good.

It's hard to find anchorages that will protect you from those kinds of changes, or at least make shifting easier. And the situation is common with wind against the tide situations (like mangrove rivers). Too bad the so-called Bahamian mooring isn't easier to do, but it is a whole lot of fuss for a one nighter.

Ann

[JebLostInSpace]

That sounds bumpy and annoying. Wind opposing current is never comfortable, but that back-and-forth over the anchor must have been incredibly frustrating.

One option you could have tried without setting another anchor would be to put a spring on your anchor rode. Tie a line onto your rode, and lead it aft and onto a winch. When you haul that line in a bit, it pivots your bow away from the anchor. In your situation, it might have been able to keep your keel misaligned from the current such that the current was consistently overpowering the wind and keeping your boat downstream. Downside to that approach is the chop would have been closer to your beam and likely rolled you a good bit.

Perhaps the better advice would be to just get more comfortable setting multiple anchors. You might have tried a bahamian mooring setup with two bow anchors. You might have continued to flip back and forth, but the boat would not have been able to move nearly as far.

You can also set a stern anchor without launching the dinghy. Simply let out additional rode on the bow anchor, drop the stern anchor in the water, and take the rode back in on the bow while letting out on the stern. If you didn't have enough rode on the bow anchor to back up to where you want the stern anchor to drop, you can always bend on another line in the bow temporarily.

Lastly, since you were surrounded by mangroves, you could potentially have taken a line ashore if that was easier than setting another anchor.

Bottom line is there are lots of options. All of them are more annoying and challenging if the weather is already rough. You'd be best off deploying whatever solution you have while the current and wind are aligned, that way when it kicks up with wind against current, you are already nice and secure.

[Jim Cate]

Dare I say that anchoring in a place with 5 to 6 knot reversing tidal streams is best avoided? It's bad enough with ~2 knots (something often experienced in our past travels), but the forces involved with higher speed currents can be devastating... as you discovered!

That must have been a really trying night!

Jim

[MicHughV]

I'm with the above on this.

I've been in that exact same situation....a few times....not by choice..just didn't think my anchorage spot thru'....

No amount of anchor selection, rode length, bridal arrangement, etc, is likely going to make much of a difference. I know, I've tried, nothing I did made any significant difference to the misery.

That spot is just to be avoided, if at all possible.

Wind against current is always a near impossible situation to anchor at and enjoy a peaceful night..

In all my cases, it was a sleepless night of near constant anchor monitoring... a royal PITA, and getting my anchors up and untangled the next morning another PITA.

So ...lesson learned....find a better anchorage for the night..

[thinwater]

Originally Posted by JebLostInSpace

... You can also set a stern anchor without launching the dinghy. Simply let out additional rode on the bow anchor, drop the stern anchor in the water, and take the rode back in on the bow while letting out on the stern....

This. Routine practice, anchoring 101. In fact, using a dinghy to set the second anchor is the hard way most of the time. Yes, I have done just this after dark in similar conditions. Easy.


This is NOT a situation to avoid. Just set two anchors, either from the start, or when it become obvious. Two anchors are often loudly argued against for current-free harbors, but they are common practice in tidal cuts. This is the problem with listening to forum experts without considering context.

[Jim Cate]

Originally Posted by thinwater

This. Routine practice, anchoring 101. In fact, using a dinghy to set the second anchor is the hard way most of the time. Yes, I have done just this after dark in similar conditions. Easy.


This is NOT a situation to avoid. Just set two anchors, either from the start, or when it become obvious. Two anchors are often loudly argued against for current-free harbors, but they are common practice in tidal cuts. This is the problem with listening to forum experts without considering context.

IMO, being held stern-to in a 6 knot current as you suggest is not a great idea. We once experienced just that when between pile moorings in the Brisbane river. We had tied up with the bow into the current and then gone ashore to deal with the paperwork relative to the mooring. When we returned some hours later a strong ebb had developed... really strong... and a standing wave had sprung up, actually breaking into our cockpit (this was in our previous boat, a retired IOR one-tonner). The forces on the boat were quite large, and despite being well supported by the piles, she was sheering about in a frightening manner, with large shock loads at times. The greater freedom to sheer when between bow and stern anchors could well end up with the boat at a significant angle to the flow, adding to the stress on anchors, cleats and rodes.

I think this IS a situation to be avoided, contrary to your advice. But then, perhaps I'm just a "forum expert" and don't really understand the context.

Jim

[Cheechako]

I have found a stern anchor to be trouble in that situation often. If the current or strain is enough, one anchor may drag due to the other anchor causing more force. Had to drop an anchor and rode once in that situation in the dark. (fortunately I bouyed it to pick up next day)
In another situation I tied the stern to an old piling and ended up with the main anchor dragging quickly. Almost ended on the rocks.
In the Bahamas I used what else than a "Bahamian moor" /twin anchors. That was a terrible mess as the boat circled around both rodes all night ending up in a twisted rode so bad it had knuckles that took 1.5 hours to untangle.

[JebLostInSpace]

I think this thread is in danger of devolving into a bunch of arguments for or against certain anchoring strategies, and is also in danger of devolving into poor forum behavior from some users who may feel that their seamanship is in question...

However, I see the disagreements here as confirmation of one of the points I attempted to articulate earlier: There are lots of different options for things you can try

People can come up with an example of when any anchoring strategy failed, but that doesn't mean they aren't good strategies in some situations. OP, you were the only one there that night to judge the forces and try anything. So anyone on the forum debating whether, for example, there was too much current over the stern for a stern anchor to be a good idea, is just guessing. We can however give you a bunch of ideas that you can keep in mind for next time. (Stern anchor, drogue, bahamian moor, line ashore, move to another anchorage). I would encourage you to keep all of these in mind in the future as potential tools to have in your anchoring toolkit. Also, it's a good idea to practice any that you are unsure of how to execute. It's much easier to decide to use one of these strategies on a dark and windy night if it's not your first time trying them.

Lastly, it occurred to me in the past couple of hours that you may have been able to improvise a drogue since you didn't have one made for the purpose. It's possible that a simple bucket on a reasonably long line off the stern might have gotten the job done. Anyway, just another suggestion to think about trying in future situations.

[JPA Cate]

Nice post, Jeb.

Just as people worry about the stresses on the rudders, when one slides off the back of a wave, one also worries about them at 6 knots from astern.

Ann

[capn_billl]

Originally Posted by Jim Cate

Dare I say that anchoring in a place with 5 to 6 knot reversing tidal streams is best avoided? It's bad enough with ~2 knots (something often experienced in our past travels), but the forces involved with higher speed currents can be devastating... as you discovered!

That must have been a really trying night!

Jim

It was like a carnival ride that night constant banging, scraping, then the sudden spin was very disconcerting.


The next day the wind shifted 45 degs, and the next tidal change we hung steady at an angle to the tidal current, and shifted just about 100 degrees 12 hours later. very manageable.

It was just a perfect wrong condition for that anchorage that night.

[capn_billl]

Thanks for all the suggestions.

I will definitely practice deploying a Bahamian moor, and a bow stern anchor in calm conditions, and have them set up, and ready to go.

[capn_billl]

Originally Posted by JPA Cate

Nice post, Jeb.

Just as people worry about the stresses on the rudders, when one slides off the back of a wave, one also worries about them at 6 knots from astern.

Ann

Good point. I thought of that, and locked them at 0.

I tried various angles to get a stable drift, but they just made the spin worse, so I locked the helm straight ahead. (no resistance to the rudders as they are parallel to the current.

[capn_billl]

Originally Posted by Cheechako

I have found a stern anchor to be trouble in that situation often. If the current or strain is enough, one anchor may drag due to the other anchor causing more force. Had to drop an anchor and rode once in that situation in the dark. (fortunately I bouyed it to pick up next day)
In another situation I tied the stern to an old piling and ended up with the main anchor dragging quickly. Almost ended on the rocks.
In the Bahamas I used what else than a "Bahamian moor" /twin anchors. That was a terrible mess as the boat circled around both rodes all night ending up in a twisted rode so bad it had knuckles that took 1.5 hours to untangle.

I saw a Youtuber after the fact that had a solution to that.

Attach the second rode about 10 to 12 feet down, and put out slack between the Tee, and the bow.

[Don C L]

What an anchoring nightmare! Hard to top that one! It doesn't sound like you were anchored badly, just caught in an unusual situation. Sounds like you got the answers needed. I'd have gone with a Bahamian moor too, there are ways to rig it so it is not a mess in the morning. And anchoring stern-to I'd also be worried about any jetsam coming down and hitting the rudder too depending on where you are.