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. 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. We haven’t looked at this in detail yet, but it looks like there might even be room to fit a Fortress or other Danforth style anchor on the second roller.
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.