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Wednesday, March 7, 2012

Warp Six: Looking Over the Anchor Gear


Neither should a ship rely on one small anchor, 
Nor life on a single hope.  
Epictetus 


There are some nights, me Boys and Girls, where well set anchors are the best of friends!

Most cruising advice is to carry three anchors; the bower (usually hanging ready at the bow), the kedge (lighter, and ready to deploy form the stern) and storm anchor (often stowed deep and in pieces, it's called upon only in the worst conditions). Many cruisers will double the bower.

This is a pretty good set (especially with the second bower) and covers most cruising for boats that don't dry out. For those that do, however, the more the merrier! But alas, small boats suffer limitations. 

Over the years, we've slowly worked out a system of six anchors. These have been chosen for flexibility and synergies among them. Here's the list:
  • Bowers - 2 x Manson @ 25lb (spade) on 10ftm of 3/16in chain and 300ft of 1/2" nylon rode, each.
  • Kedges - 2 x Northill @ 15lb (fluke) on 10ftm of 3/16in chain and 150ft of 3/8in nylon rode, each.
  • Claws -  1 x Lewmar Claw @ 22lb on 30ft of 3/16in chain, no rode, and 1 x Lewmar Claw @ 11lb, same rode set up.
In addition, we've got the following line on standby: 1 x 300ft of 1/2in nylon rode, 2 x 150ft of 3/8in nylon rode (on spools), 1 x 300ft of 1/4in nylon rode (on spool).

Standby line is used for shore tie, to extend primary rode for deep water or warping, dory line, hauling or hoisting with our 'endless' rope come-along, and any number of oddball projects that come up from time to time.

Anchor ratings are a voodoo science. They are usually given by length-of-vessel... by itself that tells you nothing about a vessel's weight, windage, and most importantly, motion in waves.

Ours are claimed to be adequate for boats considerably larger than ourselves, and this is in fact what we see in the general fleet. I am always amazed to see some multi-millon dollar yacht with a hillside's worth of windage sporting a single, dinky anchor at the bow. Hope their insurance plan delivers to Bleak Reef!

The Mansons are the largest we can comfortably pull. Several features commanded love at first sight. Their roll-bar will rotate the tip downward to engage the bottom. Normally, this is accomplished less reliably by a heavily weighted tip... weight saved goes into a broader spade; more area = more holding power on given weight. Since the weight is out of the tip, it can be sharp and slim for cutting down through moderate weed. Lloyds of London granted them their first, ultra-high holding rating.

You might have noticed the slot along the shank. In iffy bottom (where it could get stuck in rock, say), one can shackle to the slot and stand a chance of pulling it from the crown end, in case of fouling. But these are spendy suckers! We send one of the cheaper styles down if we have any doubts.

We have the pair hanging in rollers at the bow, ready to drop at a moment's notice. If we walk them out over a beach, the roll-bars make convenient grips, and balance fairly well out from our legs.

Northills are one of the early lightweight anchors designed for aircraft, and are favored by many of the local fishermen. They stow flat with cross-bar folded flat along the shank. They bite easier and in firm bottom, hold better than any other fluke anchor, for their size. They're not being made any more, but can often be found at auction (try online), or welded up (be sure to replicate angles, exactly).

Being lighter, they can be rowed out and handled with greater ease. Pretty good in weed. If we can't avoid the weed, we might put down one or both to back up the bowers. Most often we use them on broad, open beaches- they and the bowers splayed out from the quarters - where we need to fix the boat's position (over a sand-patch among rocks, say).

They do leave a fluke up. If anchoring with them, it's always against another holdfast to limit our swing from overrunning the exposed fluke... a half-hitch around that and off you go!

The Claws are broad lobed knock-offs of anchors designed for oil-rig platforms. They're not as easy to set as the others, having blunt entrances, but once in, their geometry holds well. They are reported to out-perform other types on short scope (a plus in offshore anchoring), and this seems to hold up in many's the tight anchorage.

The heavier one is often brought forward as a second bower... in light winds, the boat can turn many times a night, twisting two rodes... the claw, being set on a spool, can easily be set straight by passing the spool with any line still aboard round the fixed, bower rode.

The main use for these two, however, is to anchor in-line with the bowers in storm conditions; claws inboard and the Mansons at the end (best setting/holding anchor outboard). The effect is greater than the sum of its parts. Very strong pulls on the rode straighten the sag in the line. If the line is straight, the inboard anchor shank can lift to match the scope, and possibly pull free. In this case, however, it still acts as a catenary (resisting straightening of the rode), and thereby backing up the outboard anchor by its very presence.

If we know storm conditions are coming, and we're committed to an open anchorage, we'll set up both bowers this way, angled about 60deg to one another.

If it's to be a real bad one, we'll wing the Northills wide along the line formed by the other two (perpendicular to the expected wind), and leave their lines a bit slack. When it all comes down, we can adjust tension among the lines to spread the load.

Better to be snugged into a tight lee, however, and better yet high and dry!





14 comments:

  1. Voodoo science indeed!

    After watching a beautiful Flicka get dragged into a railroard bridge last year, I upgraded my anchors. My "big" anchor became my lunch anchor and the smaller anchor taken off the boat completely. Then I added two more anchors rated for boats twice the size of mine. I think the ratings are optimistic.

    So far, so good.

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  2. Timeless passage of seamanship experience here. Our fledgling Florida cruising was in a semi full keeled boat drawing 4 feet. Some might call this somewhat shoal draft but for the Gulf of Mexico it is way too deep for fun gunkholing. So dragging in a boat that's going to cant dangerously over if it goes aground has its own irritability factor fraught with tension. We'd wind up and around and into a apparently bulletproof little cove, ringed with southern pine trees, set out our 22 pound claw thinking it perfect in a place that could generate 6" waves at best, and feel content. Many times more than I should have I would have to stay up on anchor watch once a squall blew up or a norther started blowing down 25 to 40..... going up fwd to pluck the anchor line like a bowstring and imagining how we were going to get our full keeler off a sand bar in the morning. We had 4 anchors, used when a cane was coming, and we'd put the boat in a similar cove all spreadeagled, prostrate, a ready for sacrifice to the weather gods that be, but I never got around to setting out that 2nd anchor in daily use in our short cruising tenure in that boat. Eventually we'd have come to the same skillset trotted out in this post but we could have saved a bit of time reading this. Some novice is going to print out all these posts you've made, bind them up, and place them on the shelf next to the other classic how to's, and sleep well when the northers blow.

    ReplyDelete
    Replies
    1. Hi Gomez,

      I'd love to claim credit, but virtually every element in this approach came from someone else. The elements, over time have been hybridized and pruned by 'natural' selection. That and what'll fit in a small boat!

      Dave

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  3. My rule of thumb in small open boats (less than 20ft/6M overall)is a length of chain as long as the boat, the rest 1/4" to 1/2" nylon depending on boat size. For my daughter's 13' Peapod it's 3/16" chain, 1/4" braided nylon and a 2 Kg Lewmar Claw (Bruce hasn't made anchors less than 600 lbs for several years). For my 18' Culler Sloop Boat it's 1/4" chain, 1/2" braided nylon and a 15 Lb. Chinese version of a traditional fisherman anchor. I also carry an 8 Lb. Danforth as a spare in the Sloop Boat and some extra line. The only failure I've had was early on, when a 180 wind shift wrapped the chain around the crown of a 13 Lb. Danforth and pulled it out backwards. I no longer ever anchor to a single Danforth. I use two 8 Lb. Danforths as a mooring rig; They're used with 10' of 1/4" chain at opposite ends of 200' of 1/2" 3 strand nylon with a swivel and pendant in the middle. Takes me about half an hour to deploy if I have everything faked into a tub beforehand, and I've never had holding problems with it. Note, 18', 1200 Lb boat with low freeboard, no deckhouses and a 23' mast moored in a sheltered bay (Mystery Bay). It's a wind tunnel, but seas are not a problem.

    Glenn

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    Replies
    1. Hi Glenn,

      All sounds shipshape.

      We got a tip from a French sailing friend, who advised going with a size smaller chain, but twice as long. Double check, but usually the working loads are well in excess of the nylon. The advantage is that it's much lighter per running foot, and often, some or much of it is aboard before the anchor lifts, reducing the lift.

      In our case, we went to the 10 fathom length (2 boatlengths) of 3/16 vs. 5 fathom (1 boatlength) of 1/4. Total weigth is the same, but, as we rarely anchor in over 5 fathoms, half or more of the chain is aboard before the anchor lifts.

      Downside is that it doesn't last as long, but seems to run a good 15+ years in our waters, before it begins to look even slightly pitted.

      I'm curious... do you actually flake into the tub (figure 8s), or do you spill it in? We flaked for a while, but (on advice) tried spilling and found it to be virtually fool proof (flakes would occaisionaly tangle, once disturbed.

      Dave

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    2. Dave,

      I use the shorter, heavier chain at the end so I spend less time manhandling it over the rail, neither boat has a good, chafe resistant fairlead, something I need to make for both boats.

      I actually coil my mooring line into the tub, because it's right hand lay three strand, seems to work fine. I put one anchor in, upside down with the flukes hooked on the edge of the tub, coil in the line and set the second anchor on top of the coil. I don't shackle in the pendant until I reach the swivel in the middle (which is shackled into a thimble seized into the middle of the line) to avoid tangling the pendant in the coil.

      With braided line, I use a flat coil, whaleboat style, which is basically flemishing. All flemishes start at the edge, and work towards the center. Then I take it straight out to the edge and start another flemish coiling the opposite way of the first one and again working towards the center. Repeat, reversing with each layer until you run out of line. It is _very_ time consuming, but stores the most amount of line in the least space, and runs out without tangling. That's why the whalers coiled their tubs of harpoon line this way. I don't do it often; I agree with you about the merits of "spilling" (mountaineers call it a spaghetti pile) line, but in my very small boats there just isn't room. So I've learned to coil or 8 very quickly, and keep at least one section of the boat clear of anything likely to tangle a hastily handled line.

      Glenn

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    3. Hi Glenn,

      Thanks for the whalboat method... I'd heard that it was carefully coiled, but no description as to how.

      There's a cool web/reel system for anchor line that's been around a while now, called ANKAROLINA (Swedish company?). Works for small boats, or as a quick deploy standby on bigger ones. Here's a link:

      http://www.marinestore.com/ankarolina.html?cart=3414163014277678

      Dave

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  4. A few questions... How do you find those spendy mansons? I am thinking of upgrading, all reports I have heard so far seem good when compared to a CQR/plow.

    Also what are the details of the drums you use for storing the warp? I am keen to make some, I used them a lot in Antarctica, but on bigger vessels with fixed spools, most handy.

    I quite like the cheaper floating poly ropes for some of my spare anchor warps/shore lines. The floating rope is much easier to tow ashore in a dingy, and it don't collect as much mud or go hard over time like nylon can, only problem is it can collect lots of floating weed and stuff. But it is not as strong, or as stretchy.

    Cheers


    Cheers

    ReplyDelete
    Replies
    1. Hi Ben,

      West Marine and Fisheries Supply both carry MANSONs, and I'd bet Defender and others do as well. They're made in NZ, apparantly, so should be available world-wide.

      I also notice that ROCNA anchors (similar form but even higher tested performance) have dropped in price. They still cost more than MANSONS, but now worth a look.

      The spools we use for line are plastic, electric cord spools (cheap at most hardware stores). They hold 300ft of 1/4in and 150ft of 3/8in line.

      I've seen folks use heavier line on plastic rope spools (usually free from vendors who've sold the line off them... we usually scope near empty spools and ask if they'll hold 'em for us... often they just strip the line and give us the spool right there). A post or line through the spool acts as an axle.

      One thing to check out is a SWAIN ANCHOR REEL... see pic at:

      http://www.freewebs.com/origamiboats/apps/photos/photo?photoid=15971947

      These are DIY anchor drum haulers that are proven all over by some of the hardest-core sailors I know.

      RE Poly line - that's an interesting thought. Sometimes, especially in the light line, we don't want much stretch (300ft of 1/4in NYLON allows a lot of movement). Thanks for bring it up!

      Dave

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    2. Thanks Dave, Figured you would have a cheap and simple way. Might not fit my 16 mm line, but I do have an old plastic spool someplace for the smaller stuff... I like the idea of those Brent Swain anchor reels, most everything he does seems simple and effective, must be a pacific NW thing.

      Delete
  5. Dave Must be carefull with ROCNA - no running moors! may jerk the stem out of your craft! The set almost instantly.
    By the way had dinner with the SPINDRIFTS here in Whangarei- they cruised thru your way a few years ago....

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    Replies
    1. Hi Gary,

      Sounds GREAT!

      Good point about running sets... we've got a lot of nylon out by the time we make fast, so lots of spring on a relatively light boat. But all chain and lots of mass could play out differently!

      If you see them again, please give the SPINDRIFTers our love!

      Dave

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  6. We spent 400 days swinging to a Bruce (claw type) only dragged once on very thin sand over coral in Bequia. I took the opportunity to do some underwater research and studies it in 50+ knots dug into sand. My overall observation is very good, sets easily and perhaps more important will re set if the tide turns, by comparison the CQR plough that I observed didn't reset once broken out

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    Replies
    1. Hi BB,

      My guess is that, in GOOD bottom, a well sized and set anchor of the plow, claw and spade types should all be adequate. I'm always a bit jealous to hear of so much sand!

      Our sand bottoms tend to be in patches, which can turn out to be thin, or mud with random stretches of weed. Occasionally a silt bottom, which is the BEST. So some of the nuanced improvements (i.e., roll bar = more fluke area per pound and narrow, sharp point) are more in the way of hedging bets in dubious bottoms.

      One comment on the CQR is that I'm leery of that hinge. I've only ever met one person who lost a finger to one, and he still swears by 'em, but it just looks fail-dangerous to me.

      Dave

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