I have written before about anchoring techniques, now a bit more about the equipment involved. In the last 30 years anchors for cruising boats have undergone a huge generational shift. The “go-to” anchor in 1990 was the CQR Plow, or the Bruce. Both of these are now considered to be decidedly second rate. The development of new anchor designs has not gone in a straight line, and this is not a comprehensive review of anchor designs, just a quick summary so our selection process makes sense.
One of the first of the “new generation” of anchors was the Bügel out of Germany. It was simple to manufacture, it set quickly, and it had a new feature, a “roll bar” to ensure that it would orient correctly to the bottom.
The Bügel was a great success, even though to the eyes of a yachtsman in 1990 it certainly would have looked very odd. Stainless steel Bügels weighing 30kgs were the standard anchor that Amel chose to equip new Super Maramus with.
It was simple and robust design. Two flat, cut plates, a bent tube, and three welds. One of the downsides of this design is the flat plate that makes up the fluke. Becasue it is flat, its shape offers no resistance to bending, so the plate must be quite thick. This reduces its surface are per unit weight. Despite this very thick plate, I have never seen a Bügel that was extensively used on a crusing boat that did not have a bent tip!
The fact that the design of the Bügel was SO simple meant that anyone with the ability to cut and weld steel plate could make one in their garage. The designer/manufacturer was pretty quickly reduced to selling to the higher value added market and soon offered their anchor only in very expensive stainless steel versions. This left room in the market for incremental improvements.
One of the next major iterations in anchor design to find wide market acceptance was the Rocna, designed by Peter Smith out of New Zealand. It was more sophisticated and more complex to manufacture, but the galvanized steel versions were still much cheaper than a stainless steel Bügel. The Rocna was well marketed, and well designed. It quickly became the most common anchor seen on serious cruising boats around the world.
Superficially similar to a Bügel, it has a number of subtle design features that added to its effectiveness. Instead of being flat, the main fluke of the anchor was decidedly scoop shaped, encouraging it to bury deeper in the seabed, and better engage with the sand or mud. Small changes in the geometric relationship and weight distribution between the shank, the fluke and the tip also encouraged more rapid and deeper burying of the anchor. The shorter, stouter shank also meant that for the same weight, the surface area of the fluke could be larger, allowing it to engage more of the bottom, and that is what holds the boat.
When we bought Harmonie she came to us with a 40kg (88lb) Rocna anchor. Among Amel owners who have changed from the stainless steel Bügel, this has been pretty much the standard choice. After a trip around the world, and then some, most of our Ronca’s galvanizing has worn off, and she was starting to rust. The same was true of our chain. It used to be that re-galvanizing was something available in most ports. (There is an updated post here) Our research here indicated that it was no longer economical for small jobs like ours, it was going to actually be cheaper to go with a new anchor and chain. We needed a spare anchor anyway, so some of that was already calculated into our budget for this season.
Innovation doesn’t stop. Once the idea that anchors could be better was accepted, many people looked at Bügels and Rocnas and thought they could do one better. Many people tried, and a few have had commercial success. One of these design iterations comes from Mantus Anchors in Texas. Mantus took the basic design of a convex fluke with a roll bar, and tweaked the geometry and weight distribution to improve the anchors ability to bury in the bottom. They also designed the anchor to bolt together instead of welding. This allows them to ship the anchor in a flat box, and allows the user to dismantle and store what is other wise a very awkward shape.
Our “old boat”, the original Fetchin Ketch had a Mantus anchor that served us very well. After much thought and evaluation, we decided to upgrade Harmonie from the 88lb Rocna to a 105lb Mantus. Outside of design changes, that will give us about 10% more fluke area to dig into the bottom. The larger size also gives us an anchor rated for any conditions we might find ourselves in. I am very much NOT a fan of extra weight on the bow, but 17lbs (less than 8kg) didn’t seem a significant penalty. You can learn more about Mantus anchors, or buy one, HERE
Whenever changing the style and size of anchor, in addition to the functionality of the anchor for holding the boat, consideration has to be given to the fit of the anchor on the bow. Will the existing configuration of roller and other parts allow the new anchor to be stowed and secured safely when sailing? If not, can minor modifications be made to accommodate the changes? To help with this part of the decision process, the Mantus website has files available that can be printed and then taped together to make a full-sized 2-dimensional model of the anchor for testing.
Our Rocna’s fit on the Amel bow roller was good enough, but not perfect. Not surprising, because the roller system had been designed for a significantly smaller Bügel anchor.
Even pulled up tight, the Rocna tended to wobble a bit. Not enough to cause difficulties, but not perfect. The rollbar touched the vertical rollers on the second anchor position. The shank sat up well proud of the deck always in the way of good footing. When weighing anchor, care was required as the Rocna came onto the roller to be sure that set correctly. If not, it was too easy to get a ding in the gelcoat of the bow. These minor problems improved significantly with the addition of a Mantus Anchor Mate and a modified roller, but still not completely resolved. Our initial testing with the Mantus anchor template seemed to show that the larger anchor, with its different shape, was going to work at least as well.
After assembly of the new ground tackle, we swapped the chain and loaded the new anchor on the roller. The fit was perfect. We couldn’t be happier with the way it pulled up on the roller like they were made for each other. It touches only in places where it is supposed to, and the shank fits down low and parallel to the deck. One less thing to trip over where footing is limited.
Overall, we are excited about the new addition. Nobody ever woke up at 2AM as a squall blows through the anchorage worrying their anchor was too big, or stuck to the bottom to tightly.
We are going to be keeping the Rocna as our spare anchor. Our challenge now is figuring out the best place to stow it secure, safe, and reasonably accessible.
UPDATE: We have sold the Rocna. It was just too much of a PITA to stow. Instead our second anchor is now the pretty typical choice of a large Fortress. These are aluminum anchors that are modeled on the Danforth pattern, and can be fully disassembled to store flat.
Great post you two! We have the Rocna 40. No problems in 50+ knots for a couple of days. But all linear wind, no shifts. You’ve got me thinking. I love sleep!
Porter IBIS A54-152
Bill, I am considering a Mantus for my Maramu. Since my boat is 6000 miles away, I am trying to do this without the benefit of having the boat to measure and fit templates to. I am hoping to find someone with a Maramu that has used the Mantus to see if it might fit but no luck yet. I was thinking of the one below yours, I think it is around 85 lbs. Would you be aware of another Maramu that is carrying a Mantus by chance? Also, in your experience, is the touted resetting ability of the Mantus as good as it is touted? With a single anchor system I really feel this quality is super important. Always great to get your expert input. Best, James, SV Sueno.
I am afraid I am not aware of anyone with a Maramu and a Mantus. You might try calling Mantus. They tend to keep good track of their customers.
I think the 85 lb is a good choice for a boat the size of the Maramu. You’ll sleep well.
As for the reset characteristics, I think with any of the “new generation” of anchors they tend to not pop out when the pull direction is changed, so they don’t usually break free and need to re-set. We have watched ours spin around while staying fully buried, hardly even rolling over. We usually avoid anchoring in areas with strong reversing currents, just because it is one less thing to worry about, but we have done it without problems. The only time I set a second anchor is when I am in a narrow channel and the tidal reversal risks carrying me out over a shallow area.
Not surprisingly, there are bottom types that are more of a problem than others. Sand, soft mud, no issue. Hard, dense mud that is very cohesive, or very dense grass can sometime cause a problem. If the anchor pulls out in a reversal, it can hold onto a chunk of the bottom on top of the fluke, and that makes digging back in slower and more difficult. We had that problem one night, except it wasn’t a chunk of bottom that stuck there, but a derelict outboard motor engine!
We have sat on both our Rocna and Mantus anchors during many frontal passages and the winds clocking around have never had a problem. We don’t move. A couple weeks ago we were in the fleet anchored in Georgetown when a front came through, the winds clocked through 100 degrees and blew at 30 knots. Of the boats near us, about 5% dragged significantly, and some dragged until they fetched up on sand. It was kind of eye-opening for us about how mediocre the gear and technique of so many boats were. Anchoring in a crowd is a very rare situation for us, and we hope to keep it that way!
If you conclude that a Mantus fits, and you decide to buy one through them, email me.
Thanks for the post. I’ve been considering both Mantus and Rocna. Now I’m leaning to the Mantus
Peter de Groot, La Querida SM#207, Moss Landing CA
It is always tough to make the final decision on an anchor. It is easy to weed out the “also-rans” and end up with two or three that are at the top of the heap. The good news is that modern anchors are all so much better than what we had to chose from 20 years ago, none of them are “bad” and if you are selecting between a Rocna and a Mantus, both will hold your boat well.
Our preference has been for the Mantus, but it is a close call. The great fit we found on the Mantus on our roller and our past experience with it in some really tough conditions makes it our emotional favorite.
As a long time SF Bay sailor, some of my favorite time on the water has been in Monterey Bay. I hope you get out to enjoy it often!
Bill, Nice article! We have the 88 lbs Mantus on our SM and absolutely love it. What we are considering for a spare bow anchor is another Mantus due to the fact it can be stored disassembled. We have a rail mounted stern anchor (which could be deployed quickly in an emergency). The spare (Mantus) could be pulled out and assembled in minutes when needed.
Is the snubber depicted in the picture a Mantus product?
Kevin and Stacy Kimmey
SV Flying Free SM 057
We have always been happy with all of the things we have gotten from Mantus. They have great products and the company is run by great people.
If by “snubber” you mean the pad on the bow roller that the anchor comes up against under the roller, yes that is a Mantus product. They call it the “Anchor Mate,” not a very descriptive name, but a great product. It was the one piece of the puzzle that required some modifications to the Amel setup.
The Anchor Mate goes on the bolt that serves as the axel for the anchor roller. The problem is Amel didn’t use a bolt, they welded the axle for the roller in place! I ended up disassembling the entire stainless assembly from the bow, grinding off the welds, and installing a proper removable bolt and new grooved anchor roller.
Very interesting Bill. While I’ve only ever heard great things about the Mantus, I had always thought that I had heard that it was too big for the Super Maramu. I’m glad to hear that it definitely isn’t. I’m filing this away for when I get mine! Say hi to Karen for me.
The 105 Mantus fits in a bit of a gap in the Rocna range. The Rocna anchors go from 88lbs to 121lbs. 121 is really getting physically awfully large to fit. Although, I have to say I have not measured to be sure… And I didn’t feel I needed almost 25% more anchor than I had been using.