Friday, January 11, 2013

Ground Tackle Upgrade: Mantus Anchor and less chain

The new Mantus on the right is a great improvement
I've come to see how Aeolus undergoes evolutionary changes befitting a vessel that has been in constant use by one family for over six years now.  Many of her systems were first fixed, updated, or modified back in 2007 when we first brought her into our lives, and some of those first attempts were best efforts but lacking in later wisdom. Isn't that the way life is? Or should be? Some of my early work has stood the test of time because I err on the side of copious research and nothing has changed in that particular field. Other items are amenable to change both because of changes in the field or because of an increase in my own understanding of the topic. The ground tackle on Aeolus is a prime example of the latter.

When we first bought her she had a ground tackle system I cannot quite recall, because I so soon upgraded it to something that has served her pretty well now since that time. She came with a 35lb CQR anchor, and I think they had that on a short amount of 5/16'BBB chain and rope. I replaced that original chain with 200' of 3/8'BBB and 150' of 5/8' 3 strand nylon.

This has been our ground tackle system ever since then and it has received a much, much heavier amount of use than the typical sailing/cruising boat in the NW. Because we lived in Friday Harbor and sailed over to nearby islands so frequently, we spent over 75 nights a year on the hook during this time, and almost that much per year since then. My thinking was that though the 3/8'BBB was over sized for our Gulf, it was certainly heavy enough to do the job of putting weight down where you want it. The CQR was a classic anchor and even six years ago among the most popular for being effective. I've read that the CQR was somewhat revolutionary in its day for being a purpose designed small boat anchor that did a much better job than its predecessors.

In all our years of anchoring with this system, I can recall only a few times when we had trouble. Connover Cove on Wallace Island, BC is one of them. That poor little anchorage has a bottom that is torn to shreds and we have dragged their twice in light winds even with this heavy chain and CQR. No fun.

Well anchors have come a long way in the last five years. I've followed the news closely and with interest as test results have shown how the next generation of anchors are more effective in nearly every bottom type. New anchors like the Rocna or Delta are able to dig in more effectively, and hold much better, than any CQR or even Bruce. I'm hard to convince, and not an early adopter when it comes to my boat gear, but the weight of all the user reports and official tests makes very clear that the new anchor designs are superior to my old CQR in seemingly all ways.
Mantus comes in a flat box!

Given that we are going to sail around Vancouver Island this summer, I anticipate being anchored in several places with questionable holding and nasty winds. I would be surprised if we didn't have winds to 40 knots in one of our anchorages this summer. It is just the nature of summer on the wild Western side of Vancouver Island. With this in mind, I have taken a hard look at my ground tackle in light of these new anchor developments. The verdict: get a new anchor!

After endless hours of research and consideration, I decided to purchase a Mantus Anchor for Aeolus. They are a Rocna-like design, and differ by being held together with bolts and being open to dis-assembly. I was particular persuaded by a review from a trustworthy source in MaineSail over on Sailnet. Like me, he does his own research and documents what he finds in an honest, helpful manner. Unlike me, he pretty much sets the gold standard for independent testing of gear and stuff as a private citizen/sailor. He bought a Mantus anchor and found it held extremely well, just as well as his Rocna. So for me the choice was Rocna or Mantus, and I like the fact the Mantus can be taken apart for storage. It is a genius idea.

So my new Mantus anchor came today and I have put it together. I ordered the 35lb version. Assembly is super easy, and quite satisfying. The metals are all thick and confidence-inducing and the bolts are super stout. There is no rational reason for concern about the bolts because they far, far, far exceed the strength of the chain or any other part of your ground tackle system. Even one bolt is strong enough for the forces involved, and there are four.
Fully assembled Mantus

My next step is to use the darn thing, which I hope to do tomorrow on a little test sail. I'll report back with what I find.

But the anchor is not the only change I am making on the ground tackle. I have also been convinced by the argument that an excess of heavy chain does little good for ultimate holding power with these new anchors. Scope matters, but in even moderate winds the chain is going to be fairly straight, and I know this from experience. Then it is a question of whether the anchor holds well. The CQR doesn't consistently, the new anchors do, consistently.

So I am reducing the chain I carry on Aeolus to remove some weight in the bow. I'm going to go from 200' of 3/8" BBB to 100' of 3/8" BBB. Cutting it in half. And by cutting out 100' we will save 165 pounds in the bow! Wow! Now that is a lot of weight savings, even on a stout cruiser like a Gulf 32. I'm very curious to see how she handles differently with this reduction in weight.
Four bolts for the shank and two for the loop.

100' is still more than enough to deal with ocean bottom abrasion and the definite benefits you get from chain down low by the anchor. Research has shown that the benefits of chain are dramatic for the first feet of your rode, but quickly decrease as you surpass 50% of your overall rode. In reality, the vast majority of our anchoring around the San Juan Islands and Gulf Islands, even Desolation Sound, is in depths less than 40 feet. Often 30 or less. At these depths, and using 3:1 as standard, we would still be using all chain. But at deeper depths or at larger scope, which also happens, we would be using some of the 5/8" 3 strand nylon which is crazy strong and far surpasses the expected loads on any ground tackle for our boat.

So when I am done setting up this system we will have a Mantus 35lb anchor connected to 100' of 3/8" BBB and 250' of 5/8" 3 strand nylon. I am going to long splice an additional 100 feet of the 3 strand onto the existing 150'. Love splicing. Enough rode here to allow for 7:1 in 50 feet of water, which I hope to never have to do.
Fits the bow roller nicely and even the pin lines up!


Next is my report on using this new anchor and rode-stay tuned!

4 comments:

Unknown said...

I have seen how this mantus anchor performs and boy am I surprised. Even a small anchor of 8 pounds won over other type of the 45-pound level. Amazing anchor make. :)
- MantusAnchors.com

Brian W. said...

Hi Rachel,
Yes, it is rather amazing. I understand this in terms of how the Rocna/Mantus works. Because they dig in so aggressively due to the geometry of the shank and the pointed tip and the concave anchor face, they end up quickly buried. Once they are buried, on any normal scope, they are pulling on a tremendous volume of sea bottom in a fairly horizontal fashion.

Whereas the CQR is always trying to plow the earth to the side, the Rocna/Mantus is actually grabbing the earth. Thus, a small Mantus once set is actually held in by the mass and resistance of the sea bottom, and not the "friction" of the anchor with the bottom.

I equate the Mantus/Rocna because they are so functionally similar, though obviously different in construction. The manufacturers must distinguish themselves, but the testing shows them to be quite comparable. For my purposes, the Mantus was the better choice.

Unknown said...

Hi Brian,

What model roller do you have in the picture above? I know this post is pretty old, but it's still very helpful. Thanks!

Brian W. said...

Hi Brent,
I didn't install the roller myself and so don't that readily available. Some time ago I got interested and looked it up online and found it pretty easily. I think it may have been somewhat customized for the Gulf 32 with the support bracing. In any case, it is absolutely rock solid and fantastic! When I think of the stormy anchorages we have endured and the forces torquing on that bow roller, I have come to have complete confidence in it. And having the two rollers is quite handy not only for possibly setting two anchors off the bow, but more frequently, to have your dock line going to a state park mooring buoy over a separate roller from the already taken anchor chain. And by having it held off the bow that little amount, you don't get the buoy banging on the hull of your boat all night, which is a special form of hell.