Sunday, November 22, 2015

Anchor Management

(Ed note: This is a long post and may bore those of you who are accomplished, experienced cruisers.)

I've avoided posts on anchoring because, let's face it, there is an over-abundance of information on it out there as well as an abundance of MIS-information. In addition, we've only been cruising for a little over two years and it seemed there were many more experienced people out there to offer advice. Then there's the fact that NO topic yields more ridiculous hot-headed argument in sailing and cruising forums than anchoring. But, after having shared with a good friend our method of anchoring, I was asked to do a post to share it with others, so share it I will. Use it or discard it as you see fit.

When getting ready to leave for full-time cruising, we did due diligence on the whole anchoring issue. We read all the chapters in the most well-known cruising how-to books, we read the advertising promo on all of the anchor manufacturer websites, we scoured the vendor aisles of boat shows and we talked to tons of people. We had an oversized CQR (39# on a 27' boat) on our first boat, Nomad, which seemed to do well on the lake in the muddy bottom. Kintala came with a not-oversized CQR, which also seemed to do OK on the lake, although we did drag once while we had a half dozen boats rafted up to us. Knowing we were going to be in much rougher waters and many different bottom types, we began the search for a good cruising anchor to replace it.

I'm not exactly sure how we found out about the Mantus anchor initially, but after researching the details, it seemed like a good choice. It was robust, it had great reviews and, most importantly, it was affordable which allowed us to purchase a size larger than the recommended size.


The Mantus after installation with Kintala still on the hard.
I remember the day the Mantus 65 was delivered to Tradewinds Marina where we had the boat on the hard getting her ready for the truck voyage to Oak Harbor. I believe the words out of Tim's mouth when he saw the box were, "Are you kidding me?" He grumbled through the whole assembly. He grumbled through the mounting. He still grumbles through every morning of pulling it up, but not because it's a bad anchor or because he doesn't want it, only because he doesn't have a shiny electric windlass to pull it up with. The Mantus anchor was one of the few major purchasing decisions that I got right. And so very right it is.

One of the things that few people realize about anchoring is the fact that only half of it is technique. The other half is the anchor itself. While I firmly believe that every single boat out there should have a new generation anchor of some sort (Mantus, Rocna, or similar), many of the other anchors will do just fine if they are sufficiently oversized. And this we found out our first trip over to the Bahamas. So point one:  

Buy the absolute biggest anchor that your bow roller / windlass / back / biceps / budget can handle.

Learning to sail on a rural lake in Illinois never afforded us the opportunity to actually see our anchor on the bottom, in spite of the fact that the water in Carlyle Lake was rarely more than 8' deep. The lake was a runoff of local farm land and, as a result, was filled with sediment and the byproduct of our modern chemical fertilization methods, not to mention the somewhat less offensive byproduct of the cattle. It wasn't until we reached Elliott Key in Biscayne Bay that we even saw the anchor at all, and that was just barely. When we crossed to the Bahamas early in 2014 and began our trek across the Abacos, it was an epiphany. We had an anchor! We could actually see it on the bottom through clear water!

A well set anchor in sandy bottom

After traveling across the northern Abacos and anchoring in the anchorage just outside Green Turtle Cay, my curiosity got the best of me. I had been listening to anchoring gurus tell me that I needed to back down on the anchor to set it, and I began to wonder how many RPMs it really takes to stretch 75 or 80 feet of chain out fully extended. I wanted to be sure that I had been applying sufficient power. In this anchorage we had laid out 75 feet of chain, backing slowly as we released it so we didn't pile up the chain, then backing on it to set it. After completing this, our standard procedure, I talked Tim into donning his snorkle equipment and swimming out to a position directly over the anchor to do a small test.

We had agreed on some hand signals, him telling me to back down until he could see that the chain was fully extended, and then I would apply power to set it. He motioned me to back and I did. After a few moments his hand signal to back became more vigorous. I backed harder. Another moment and his head popped up out of the water and he shouted, "Are you backing?? Because nothing is happening. The chain is not moving." I had been using nearly 2000 RPM and was unable to even move the accumulate length of chain from its position in the sand where we had dropped it. I revved the Westerbeast to 2500 RPM. Still no movement in the chain by the anchor.  We were quite surprised, to say the least. It led us to the conclusion that a 50hp motor and a typical bow roller setup are not strong enough to drag 75 feet of chain taut, let alone pull on it hard enough to set a 65-pound anchor.

Over the next few weeks, we traveled around the Bahamas and began to take notice of our chain more closely. When we anchored off Rose Island northeast of Nassau, we saw our chain form a perfectly round spiral as the wild current there continued to swing us 180° every 12 hours. The winds were sometimes 18-25 knots and Kintala would travel back and forth as the current changed, the chain continuing to add to the spiral, but never straightening out. We began to rethink our anchoring strategy.


A video of our anchor in the anchorage south of Bimini

 
Over the next few months we gradually began to refine a new technique for us. A side note - over this time, as well, we have moved from having headsets to not having headsets (they succumbed to the harsh marine environment), to using whistles. And this brings me to point two:

When anchoring, be sure that whatever communication you choose is easy and of limited stress. Spend whatever money you have to in order to assure this. It will be the best money you spend. If you choose to use hand or whistle signals, be sure they are clearly defined beforehand.

After quite a few months, we've settle on the following technique and it's working well. So well, in fact, that when we withstood a 56 knot gust and subsequent high-40s for 5 hours at Foxtown, the anchor held well enough that the bow chock broke in spite of using a doubled snubber. Boats around us dragged, but Kintala stood her ground in the face of 5 foot waves and green water over the bow. Here is the procedure, and I'm going to use a depth of 8 feet as an example because it's the most common depth we anchor in while in the Bahamas.

First, we talk. Tim gets the anchor ready to deploy then comes back to the cockpit (since we have no more headsets) and we talk about where we might want to anchor. We drive around and look at possible spaces. We make a decision, figure the scope we need and how much rode we'll end up with, and he goes forward. From this point on we use the whistle signals we've devised. In our example, we have the 8-foot depth plus 4 feet to the bow plus 2 feet of tide = 14 feet, so our 5:1 scope (no storms predicted otherwise it would be 7:1) will be 70 feet minimum.

Next, Tim signals me that we are at the desired location. If I've done my job at the helm well, I will have coasted there and won't have to reverse much to stop the boat. He starts by laying out 25 feet of chain as I leave the boat in reverse with no power.  If there's any wind at all, the bow will swing out to one side as he lets the chain out slowly. When we're in the islands I'm usually in my bare feet and, as we back slowly, I can feel the instant the Mantus point digs in. There is a subtle change in my balance and the bow swings. We allow the idle speed to stretch the chain a bit, but not so much as to dislodge the tip. As soon as the point digs in, Tim lets out the next 25 feet, again with me slowly backing. The bow again swings out to one side, and then swings back as the chain is stretched out. At this point we do a hard set. I slowly bring the engine up to at least 2200 RPM. The bow dips slightly, the chain stretches fully, and the anchor is set.

Next, Tim lets out the remaining chain of our scope, at this point about 20 feet, and again as I slowly back. The boat goes into neutral and as it rebounds slightly on the chain Tim sets the snubber. (More on our snubber below.) Boat goes back into reverse but no power and I slowly back on the snubber. Once the snubber is fully extended, I set the anchor a final time, revving the engine slowly up to 2200 RPM until the bow swings back forward and dips slightly.

That's the basic technique that we developed, the main difference from everything else we have read and heard being the fact that we pause at 25 feet and set the anchor twice once at 50 feet and once at the full length. We set it once in the middle of the layout because it became evident that the motor had insufficient power to fully stretch out the weight of the chain and set the anchor, leaving the anchor un-set in most instances. There are several things worth noting, though, about other anchoring scenarios in less than perfect conditions.

One, is how the procedure changes in soft mud bottoms. We see countless people come into anchorages with soft mud bottoms, drop the anchor and immediately begin to back on them at something akin to 1800 RPM. The anchor skips across the bottom and after a half dozen tries they give up saying that the anchorage sucks. We've learned that when anchoring in soft mud bottoms, we set the anchor on the bottom with about 25 feet of chain (again 8 foot depth) and then I hold our position with the engine so that no pull is on the chain. Then we sit there and look at each other and the beautiful scenery for at least five minutes. We let the weight of the anchor settle slowly through the soft mud to the harder mud below it. Then we go ahead with the technique above.

Let the anchor settle through soft muddy or silted bottoms to the harder substrate below, then set it.

The other issue is when dealing with higher winds. The higher the wind, the longer the scope, so make sure there is adequate swing room for the longer scope. We usually try to pick a spot with enough room for 7:1, anchor with 5:1, and then have room to let out more rode if needed, should a storm pop up. During the storm at Foxtown, we had 110 feet of chain deployed which was 8:1. We now have a new length of chain that's 200 ft and we would have let even more out in that blow with this chain. In harder winds, also, the wind may back us too quickly so I sometimes have to use some forward power to slow us down. If I don't do this then the anchor can skip.

A word about the snubber. We constructed a custom snubber for our boat. We used 25 feet of three strand, stretchy nylon. Tim threaded the line through  a Mantus chain hook, folded the line in half, threaded the lines through a piece of fire hose chafe guard and spliced loops on each end sufficiently large to go over our bow cleat. This one doubled snubber goes through one bow chock and over one bow cleat. Some boats do better with each end of the snubber going to two different bow chocks and cleats, but we have found that Kintala rides at anchor better with a snubber arrangement going only through one chock and onto one cleat. Every boat is different, so what works on Kintala may not be the best arrangement for your boat. What arrangement you use is not as important as the fact that you use a snubber.

Use a snubber to take the load off of the bow roller and windlass. Make it from stretchy nylon.

The last point worth mentioning from our experience is that of making sure that you have the right chain. Our chain had been replaced at one point and the owner at that time, attempting to save money, bought proof coil chain. It is the only chain that does not work in our windlass, so every time Tim tried to use the gypsy to advance the chain, it would skip. Now that we have the correct chain on there it moves swiftly and quietly. So....last point -

Don't skimp on your ground tackle. It is the single most important thing on your boat.


See the Mantus?  No? That's the way it should be!

 As a final note, we are not paid by Mantus and receive no compensation for our positive reviews, other than many peaceful night's sleep and some of the best customer service in the marine industry.

4 comments:

SV Pelagia said...

Completely agree! Add also USE ALL CHAIN RODE. In Mexico, the new cruisers (often just off the Baja HaHa) often come down with chain/line combo rodes. If they stay longer than a season (or, as many do, return the following year), then soon switch to all chain.

(On a typical cruising boat, the extra weight added by all chain is minimal compared to everything else... better to have less water than a skimpy anchoring system).

As for anchoring signals, we rely (usually successfully) on pre-worked-out hand signals (and the occasional evil eye (when things aren't going so well, which of course is rarely 😢). Headsets block out other sounds (such as other cruisers laughing at you) and look odd to us. Question, have you ever seen a European boat using headsets? Seems more an american thing. (Then again, European boats also have a penchant for extra fenders...).

David
sailing-pelagia.blogspot.ca

Deb said...

David the headsets we used were the low profile type that had a small in ear speaker in only one ear and only showed a thin microphone near your face. They were almost impossible to see from more than 10 feet away. They also allowed all outside noise in since they didn't have ear cups so safety was never an issue. If they hadn't broken we would still be using them today as I found the good communication to be a huge contributor to safety on Kintala. We used them also when we were docking and departing as well as in fog or near coral if I was on the bow.

Agree wholeheartedly on the chain but we still have 200' chain attached to 200' of rode just in case were ever anchoring in deep water. So far the deepest we've anchored in is 34'

Greg Martin said...

I completely agree on your anchor setting technique. We independently learned it this year - our first season with a 65# mantus and 3/8 chain. In water less than 20 feet, we let out 50 feet of chain and set with a backdown in reverse and then let out the rest of the scope. Yes, otherwise, the W50 is not powerful enough to put enough tension on the chain.

Greg Martin
S/V Serenity, T42 #29
Boston

Donald said...

I completely agree. One of the most important steps in the process is the one where you talk it over in the cockpit first. We do the same thing and there's never any drama when we actually set the hook since we know exactly what each of us is going to do. We discuss the depth, where we want the boat to lie and where we want to drop the hook to make that happen. I think the biggest novice mistake in anchoring is dropping the hook where you want the boat to end up. I've seen that a lot where there's a perfect gap between anchored boats for another boat to fit. They pull in and drop the anchor right smack dab in the middle of that spot then drift back to set the hook and end up 10 feet from another boat.