Over the past week, there has been a trough lying over French Polynesia. The trough has remained pretty much stationary just east of Tahiti, lying in a North-South Direction. It’s mid-February, which makes it the height of the rainy season in this part of the South Pacific. As a result, this trough has given birth to some spectacular tropical thunderstorms. Here is my Rocna Anchor review.
Rocna Holding During Extended Gales
For three straight nights, we have seen an accumulative total of six hours of winds exceeding 35kts. Over an hour and twenty of over 40kts constant wind, and a ten minute period of winds gusting from 47kts to 52kts. Winds so strong that our bimini was ripped clean off of our boat. The bimini supports ripped right out of the deck! The question we’ve been asked is, how did your Rocna anchor perform? Here is my review on the Rocna anchor, after over 1,600 nights at anchor using a Rocna.
Rocna Anchor Model
Our boat is a Lagoon 380 catamaran, which fully loaded tips the scales at just under 11,000kg or around 24, 000lbs. For a catamaran of this size, Rocna recommends an anchor of 25kg/55lbs. Rocna specifically states in their product literature that there is no need to oversize their anchors when selecting an anchor for your boat as the anchor is already ‘oversized’ above design specs.
We went for an anchor one size bigger than recommended. Mostly by mistake! You see when we were doing all the research needed to become a cruiser, we were thinking of a much bigger boat. A 45-foot Lagoon 450. What we ended up with was a 38-foot 380. Lost in the myriad of research and boating equipment options, we completely forgot to downsize the anchor when we went Rocna shopping.
Am I disappointed that we accidentally went over-specification with our anchor? Absolutely not! The small weight increase on the bow and minor price difference, between the 25kg/55lb anchor and the 33kg/73lb Rocna we ended up with, is a tiny price to pay for the increase in performance it affords.
Having a slightly oversized anchor gives us the ability to anchor in tighter anchorages with reduced scope, or closer to reefs than we would have been able to with an appropriately sized anchor. This has proven to be valuable over the years when we’ve had to tuck into a small cove, to get out of some wicked fetch, or needed to anchor a few hundred feet off of a reef in the South Pacific. Where the anchoring choices were close to the reef, or above loads of coral bommies, on which we were likely to wrap the chain around under the boat, we had our choice because of our large anchor.
Ability to Reset
I have taken a few looks at the sea bed after a big blow where the wind has changed directions rapidly during a storm, and what I’ve seen is that the anchor tends to reset in less than one anchor length of where it rotated, even where the wind change has exceeded 90 degrees.
To aid in re-setting and to take advantage of the catenary effect of the chain (which in our case is 10mm or 3/8), we try to drop 7 to 1 scope where space permits. 5 to 1 in tighter anchorages. In very shallow anchorages where the total depth is less than 2m or 6.5ft, we like to drop a little extra chain to 10 to 1 if space permits.
When very in very deep anchorages, we are happy with less than 3 to 1, and on one occasion when we had no choice but to anchor in 40m/130ft of water we chucked out all of our 100m/330ft of chain which gave us a little over 2.5 to 1 scope. That night we had a solid three hours of gale-force winds, and the Rocna anchor held us perfectly in position.
The Time the Rocna Anchor Dragged
We have dragged once. Ironically, it happened in Egmont, Grenada which is a well-known hurricane hole. We were seeking shelter from Hurricane Irma, which at that stage, was looking as if it would come within a hundred miles of Grenada. What we ended up getting was less than 10kts of wind, and we managed to drag!
How we dragged, I really don’t have a clue. We always set our anchor. Wait a few minutes, then slowly back up and increase the RPMs on both of our engines to 2,000rpm a side. Until all four of us agree that we aren’t dragging by looking at our own traverse marks on the land, and watching that the chain doesn’t bounce.
Like all stressful things that happen when living on a boat, they happen in the middle of the night. The anchor alarm went off at 2 am. We went on deck, and fortunately, we couldn’t have chosen a better place for a 2 am re-anchoring mission. Egmont is surrounded by a moderately steep sloping terrain on all four sides. I also happens to be one of the wealthier neighborhoods of Grenada. When we got on deck, it was bright as if we were on a football field, all the big houses had bright spotlights aiming away from their homes towards the water.
We tried re-anchoring in the same place two more times, and on both occasions, the anchor pulled effortlessly across the surface. All that we can think of is that the surface must have been covered in dense turtle grass and that when we turned in the gentle breeze, our Rhonda, as we call our Rocna turned and could not reset herself.
Rocna Performance in Dense Sea Grass
Normally, the anchor sets first time with ease, except when anchoring in areas of dense seagrass. When anchoring in dense grass, the technique we have found that works is to drop the anchor and wait for five, sometimes even 15 minutes, before pulling back on the anchor to test. This technique usually results in the Rocna setting itself on the first attempt.
Anchoring in Sand over Rock or Coral
Another area where it is possible to get a false sense of security is when anchoring in a thin layer of sand over rock or coral. Sometimes you can get lucky and find a deep section of sand, other times the anchor just slides along the rock bottom. With only two or three inches of sand covering the bottom, there is nothing for the anchor to set in. I don’t know of an anchor that can hold in the sand over rock or coral.
Generally, it’s best to move to another section of the anchorage or atoll and try again. In some anchorages in the Tuamotus in French Polynesia, this may even mean moving a couple of miles away from the initial anchoring spot before finding a section of sand that will hold.
The anchor itself is very well made. I do know there was a period, when shortly after moving their manufacturing to China, that there were some cases of Rocna anchors bending their shafts. This was caused by the change in the quality of steel that was being used, which resulted in weaker shafts.
To Rocna’s credit, I have never heard of an owner from this period not having their anchor exchanged under warranty.
The quality of manufacturing was improved a number of years ago, and I am happy with the construction and quality of materials used in our Rocna.
Rocna Galvanizing Issue
One area where Rocna has dropped the ball is the quality of their galvanizing. We’re on our second Rocna, as the galvanizing on our first Rocna wore off in less than a year. We put in a warranty claim that was denied, as corrosion protection and galvanizing aren’t covered under warranty. I sent a response email to the head of marketing, expressing my displeasure with our anchor that was less than a year old, and to his credit, he swiftly approved the warranty claim. We walked into the closest dealer, which at the time was Budget Marine in St. Marteen, the next day, and our replacement anchor was wrapped up and waiting for us.
We’ve now had the replacement anchor for over three years, and the galvanizing has held up reasonably well. Having the anchor re-galvanized is on our list of to-do jobs when we get to New Zealand, hopefully later this year. The galvanizing is probably good for another two or three years, which in the grand scheme of things isn’t too bad for something that spends over 300 days a year at the bottom of an anchorage in corrosive seawater.
If I were to buy another Rocna anchor for a future boat, I would consider having the anchor independently galvanized after purchasing it. Just to be overly cautious. To make sure I didn’t have corrosion problems in some remote area of the world far from a galvanizing facility.
Rocna Vs. Mantus Anchor
I have not tried a Mantus. We have friends who love their Mantus anchors, so I can’t comment on the holding ability or quality. What I have however gleaned from the Rocna vs. Mantus debate is that many cruisers who have chosen Mantus have done so for one of two reasons.
Mantus makes a bunch of exceptionally high-quality marine products, including the Mantus headlamps which I have found to be light years ahead of any other headlamp in terms of quality, brightness, and ease of use.
The other deciding factor we often hear is that Mantus is made in the USA, and Rocna is made in China. As we see with Apple products, just because something is made in China doesn’t mean it’s of inferior quality. If the company contracting out pays a premium price, they receive a premium product. I believe this to be the case with Rocna, and other than for patriotic reasons, I don’t think this argument has merit.
We spent hours evaluating the two anchors, and in the end, decided that the bolts on the Mantus that tie the shank to the fluke were a point of failure that we couldn’t accept. That said, I have never heard of anyone having a bolt break on their Mantus.
The truth is that both the Rocna and Mantus are equally good anchors, and anyone purchasing either of these new high-performing new generating anchors is sure to sleep well at night, especially if you sneak up one anchor size.
Where to Buy
When anchor shopping we looked long and hard, and we were surprised to find the best prices on Amazon. And I’m not only saying that because I’d like you to click on one of my Amazon affiliate links should you chose to buy your Rocna or Mantus anchor. As much as it would be great if you shop through Amazon, I must warn you that I do feel really bad for the poor UPS guy, who has to lug an anchor up the garden path to your front door.
For more product reviews take a look at our gear review section on the website.