Anchor replacement

[Jim S]

We are all seeking the best anchor for the conditions anticipated.  Those cruising in areas where high sustained winds are common and expected, a much larger "working anchor" would be a logical choice.  Those cruising in milder conditions where predominately moderate winds are common and expected, a middle size working anchor with a larger "storm anchor" as a back-up would seem a logical choice . 

It is easy to be discussing anchors as if we all are cruising the same grounds, but Phantom cruises in moderate conditions and Dave and Della in extreme high latitudes.  We will by necessity use much different working anchors.  It would be super-overkill for me to use a 65# Mantus as a working anchor on the Texas Coast and it would be folly for Dave and Della to use a 22# Delta as a working anchor in Alaska.  We, hopefully as prudent and knowledgeable boaters, will evaluate our specific needs and make the best choice.  It is our boats and our safety that is at stake.  There is a lot of written material by those who have gone before us that will give us guidance with their successes and failures.

Note: when using the term "working and storm" anchors, I also include all appropriate ground tackle that would accompany the anchors.

[P69]

Thanks everyone for your advice on this question. After sorting through all the valuable and utterly useless crap ( on other sources), I have decided my ground tackle.

All 3-strand is existing, all chain is to be bought.

Primary: 45 lb mantus (need to buy), 200' 5/16" chain, 100' 5/8" 3-strand nylon
Secondary: 35 lb danforth (existing), 200' chain, 300' 3-strand nylon
Stern: ~20lb danforth (existing), 50' 5/16" chain, 150 or 200' 5/8" 3-strand nylon
Kedge: 12ish pound danforth (maybe 7 or 10lb fortress) (need to buy), 10' 1/4" chain, 200' 3/8" 3-strand nylon
Spare anchor: 45lb bruce (existing). I might swap bank and forth  with the danforth at the bow.

I'll also make a small handful of kellets later, maybe.

Later I might think about a 65lb mantus for hurricanes, but I'll see how this setup holds.

[Della and Dave]

Thanks for the recommendation for the Attainable Adventure Cruising.  They have a lot of good high latitude advice there.  It's a bit of money, but not bad in the grand scheme of things. 

P69:  From all the reading I have been doing, your setup looks like a good one to me, but I do have two questions if you don't mind.  As I read the charts, that seems to follow the "one size bigger" advice, if not one and a half depending on how you read the charts. 

1) Why the Mantus over the Rocna?  The test data seems to be very similar. Did you go with the one with the bolts?  Both seem to have had Quality Control issues in the past, but differant ones. 

2) Are you going to spring for G4 (high test) chain, or just BBB?  I am as also curious about how you came to the decision on 200 ft as opposed to some other number. Was it a weight thing?  I'm also curious if a gypsy for 5/16 BBB will work on 5/16 G4.  Can't find the answer on Lewmar's web site. 

[P69]

Della and Dave,


1.  Mantus and Rocna  seem similar enough, went with price. Also, can dismantle and stow mantus below for passages.  If I run across an outstanding reason to buy rocna, might do that, but so far, they seem about the same.

2.  5/16" G4, yes.  200 was around number and seemed adequate.   I think more per rode would be too heavy.  I might have 150' on secondary instead of 200'. 1st chain supply has 550 drum and once I divide that up among two bow, one stern, I'll have some extra.  the price difference between 275 drum and a 550' drum was not that much. I even got a quote for a 400' drum and for just a $100 or so more, I could get the 550' drum.

It just didn't make sense to not buy the 550' drum. I can always use the extra chain for wrapping around trees when hurricanes blow through.

The actual length on each rode might be different once laid out and when I see what its.  I have a maxwell windlass with a 5/16" gypsy.  Don';t know  about BBB vs HT gypsy compatibility.

[Risto and Liz]

For my two cents... We just tried our new 44#Rocna and were REALLY impressed with how it set. It is now on only 25' of 5/16 and 5/8" three strand rode. This will change tp 200' of 5/16" HT and 175' of 5/8" 8 plait so save room.
We plan to have a secondary 35# Delta on 50' of 5/16" HT and 200' of 5/8" 3 strand.
I would argue that time spent planning for riding out a Cat 3 hurricane would maybe be spent on weather routing and either being out of the hurricane zone or someplace on the hard.
You don't get much for 2¢

[P69]

Risto,

Thanks for your pennies.  It's reassuring to hear the rocna holds our boats well. Regarding hurricanes, I live in a hurricane zone (Gulf coast) and can't go hauling out every time one threatens. Fortunately, there is  creek  I can go up about a mile away that offers very good protection with plenty of deep-rooted trees and a soft shoreline. Once I get the Mantus, I'll have four anchors that are 35 lbs  to 45 lbs  to set to windward and three to four tie points on shore. So, I should be fine. Just have to make sure I am out of range of the falling pine trees.

[Della and Dave]

I found an interesting write up on Scope, Catenary, Mixed Rodes and Kellets on Peter's Smith's personal web site.  He is the guy that invented the Rocna Anchor and has done a lot of very high latitude cruising.  He also has some great pictures of Antarctica and the Drake Passage.  http://www.petersmith.net.nz/boat-anchors/catenary.php  He obviously has a Rocna Bias, but his data on Rodes and the catenary math is interesting and doesn't really care about the anchor attached. 

After reading on the Attainable Adventures site, one fly in the ointment, as they say it, for going to really high strength chain, like G70, is that the shackles aren't up to the chain strength unless you really oversize them, and then they won't fit through the link.  One way of getting around this is to order your chain with extra large end links, which I guess is possible with some chain manufacturers, but you would of course loose the ability to cut it shorter later, and it is a lot more expensive to do that.   

On the Gypsy, I finally found the answer for our windless, sort of, and there is a small difference in chain link length between G4 (HighTest) and BBB, (1.000 inch for 5/16 BBB and 1.030 for 5/16 G4) so Lewmar recommends a different gypsy for G4 5/16 chain than for BBB, however, for other Lewmar windlasses, they don't.  I suspect that I might still be able to get away with the existing Gypsy, .030 is pretty small difference.   

[Maddie]

for going to really high strength chain, like G70, is that the shackles aren't up to the chain strength unless you really oversize them, and then they won't fit through the link.  One way of getting around this is to order your chain with extra large end links, which I guess is possible with some chain manufacturers, but you would of course loose the ability to cut it shorter later, and it is a lot more expensive to do that.

I guess a titanium shackle is out of the question due to galvanic corrosion?

[Della and Dave]

Titanium would seem to be an option.   It is on the far cathodic end of galvanic scale, next to gold, so compared to zinc, it is really far apart.  That means that the shackle would be safe, but might accelerate the loss of the zinc in the galvanize coating on the chain might be an issue. Because the chain and anchor are really big in terms of surface area compared to the shackle, my guess is that it wouldn't be an issue.  In addition, Titanium forms a very tenacious passive film and can be surface hardened by exposure to elevated temperatures in air, and it makes it a really pretty blue.  

On strength, a 13/32 Titan Titanium Bow Shackle is rated at a "Maximum safe load" of 9,922 lb, and a "Safe Working Load" of 4,961.  5/16 Grade 70 Chain, according to West Marine is good for MWL: 4,700lb., Breaking Strength: 14,100 lb.  Titan doesn't supply a breaking strength, so the only comparison available is the Maximum safe load.  It looks like based on that the weak link is the chain, not the shackle.  It is pricey though, $46 bucks, but at least you only need one, at least for the Rocna with the slot in the end so you can pass the u part of the shackle through.  

[Risto and Liz]

We have a 20kg Rocna with 200 feet of 5/16" HT chain (U.S.) with another 175 feet of 5/8" Yale nylon Brait. We may never get to the Brait but in storm conditions when we will want to veer lots of anchor rode it should provide a reliable shock absorber.
Going to the 200' of 5/16" chain lowered the bow by about 1". (Kind of like having a linebacker on the foredeck :-)
We also jus got an FX16 Fortress. I bought 40' of 5/16" HT before I read the Fortress information. They recommend 10'! So I used 15' and 200' of 9/16" Sampson Superstrong. We plan to keep the rode in a bag in the lazarette with the anchor sitting on top. I think this will be a good option as a kedge as it will be easy to get into the dinghy in the event of a grounding.
We may use a 35# delta as a secondary but I plan to try the Fortress under load first.