The Scoop on Scope

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SailboatOwners.com

It's that time of year again --- anchorages are real crowded. It seems that everybody who owns a sailboat is out cruising and the charter gang is out as well. Even if you're in your anchorage early, others are likely to come in and crowd you a bit. If you are the late arrival, maybe you're trying to tuck into a spot that's pretty snug. The textbooks are clear: Take a reading off your depth sounder, adjust for the tidal fluctuation, add the distance your transducer is below the water line, add the distance your bow roller is above the water line, multiply the total by seven for a rode that's a mix of rope and chain and by three for an all chain rode, and let out that much rode. This time of year that's likely to have you bumping into other boats all night... and bound to make you pretty unpopular in the anchorage. In moderate conditions (5-15 knots of wind and currents less than 2 knots), what's the minimum scope you will use? What are your strategies for dealing with a crowded anchorage as either the crowd-er or the crowd-ee? Share your thoughts and be sure to vote in the quiz on the bottom of the homepage. (Quiz by Gary Wyngarden)
 
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David Foster

Overnight - 7 times

Of course, the wind and waves can (and do!) change overnight. So we get 7 times the max depth, or we move to another location where we can get the right scope. Another solution we have used (with a full scope) is to tie the stern off on the shore to hold the boat in position away from other boats. I've not yet been in an anchorage (in the Great Lakes, or BVI's) where this would not work. If did run into the problem often, I would switch to a chain rode, and 5 times standard. But I wouldn't compromise the safety of our boat and of our neighbors with a substandard scope. I have used a scope of ten times the bow to bottom depth in a big blow - or with one in the forecast. And we have used less scope for a lunch stop. David Lady Lillie
 
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Paul

5:1 on chain

We have 85 feet of chain, so we can usually do 5:1. If it was so crowded that we had to shorten beyond that, we'd go somewhere else. Might as well be in a marina. Paul sv Escape Artist h336
 
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Ben

5 - 7:1

My boat is a daysailor, not a cruiser, so I don't often get the anchor out of storage. When I do, my anchor and about 6 feet of chain are slightly oversized for the size of the boat, so I can get away with a little less scope than recomended. I also have to agree w/ Paul, though. About the only reason I would anchor in a crowd of boats again will be on the next 4th of July. Beyond that, I view sailing as a means to get away from everyone except the close friends I bring with me.
 
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Brent

5:1

We use a 5:1 scope with a mix rode/chain line (30 ft chain / 250 ft rode). Have also used 3:1 on calm stops when we weren't staying long. If we anticipate a busy anchorage or if it looks busy when we arrive we'll throw an anchor off the stern and wrap around a tree on shore (I think it's called European anchoring but I could be wrong).
 
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tomD

Short scope anchors

If you are going to hang out in the most popular anchorages--hence the most crowded, it may be worthwhile doing the shore-tie thing with bows out and a line back to a rockbolt or tree, if that's what the regulary thing is in that anchorage: or get a Bruce anchor. They will set in pretty well on short scope, even 4:1 if you have to. A well-set Fortress will likely hold better in a blow but for normal conditions, they work well, handle a 180 due to tides and currents by resetting. Especially with 30 ft of chain.
 
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John McDowell

Crowded Anchorage

In a crowded anchorage, with the probable chance of bumping into other boats I would do the following. I wouuld put down 2 anchors next to each other. I would probably use a 4 to 1 ratio with 20' of chain and 1/2" anchor line. This is not the ideal condition but better than beating the sides of your neighbors.
 
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Roger P.

Never too tight of an Anchorage

I've read the other responses and as to use a pun that fits is that they "missed the boat". Ideally, everyone (especially myself) would love to anchor in an excluded area with a great holding bottom. Unfortunately, the good anchorages are well known and, like the article stated, even if you are early, there is always some joker who comes in after you and whom has no clue on proper anchoring techniques. If someone invades your swing room, don't be shy in addressing your concerns with the other skipper and request that he/she move. If the person is a good skipper, they will relocate without any further problem. Unfortunately, if unsuccessful, you may have to be the one to move in order to have peace of mind. Most people are generally lazy and anchor with only one anchor. Depending on the depth, the swing radius could be quite large and in a tight anchorage, there will be a lot of overlapping swings. This is fine if the wind conditions to blow all night; however, if the wind stops, the boats are free to float (at will) and you may end of up playing bumper boats all night long and it is no fun - seen it happen hundreds of time. I am very conservative when I anchor and like to sleep all night. When I anchor, I always use a 7:1 scope even in very crowded anchorages. Even in over-crowded anchorages, there is always some area that nobody will attempt to anchor, because it is either too close to shore or to an obstruction (bouy or some other time of marker) even though there is sufficient depth, but very little swinging room. This is when I like to use an anchoring method described in Chapman's Book of Piloting (a book I consider the bible of boating). In this case, you use two anchors: your bow (primary anchor) and a lunch hook, if you don't have another larger anchor. THE METHOD: You enter the anchorage and head directy for the obstruction (or closest point to shore), turn back out to sea and drop your secondary anchor (or lunch hook) from the stern. Slowly motor outwards (180 degrees out) and set the stern anchor and continue to motor outwards, paying out scope until you reach the end of the rode. Then put the engine in neutral and drop the main (primary) anchor. Then pull in on the stern anchor rode until you get enough scope out on the bow anchor to set it (using the engine). Once set, you continue to pull on the stern anchor while paying out the bow anchor until you have equal amounts of scope out on each. Then you transfer the stern anchor rode to the bow and tie it off. What this does is that it changes the swing radius of the boat to the length of the boat. For example, if you have a 30 foot boat, your swing radius is 30 feet as the 2 anchors (at 180 degrees apart) will allow the boat the swing with the changes in wind, but only to the length of the boat (in this case 30 feet). I've used this anchoring method more times than I can remember (over my 31 years of sailing) and in boats to 50 feet and in varying wind conditions. It is like swinging on a bouy. I have found some very nice anchoring spots where I can claim anytime because no one else knows how to anchor in such a tight spot and I'm no where near any other boats. It is like having a reserved parking spot. The beauty of this method is that, no matter the wind condition/direction, the boat is only pulling on one anchor at a time which guarantees your set will stay. The only downer to this method is that with the boat swinging all night, the two rodes get wrapped around each other (at the bow point), which is easily resolved the next morning by untying the one rode that is not pulling (or tight) and unwrap it. A few extra minutes is worth a night of worry. The other downer is pulling up the second anchor. This is best accomplished with a dinghy, but if you don't have a dinghy and can't free both anchors by reversing the method in which you dropped them, you can always just tie a fender onto one anchor rode and drop everything over the side and retrieve the one anchor. Then retrieve the fender and the second anchor separately. Again, it is your choice, but for a peaceful night's sleep, I like this method. I've used this in the Caribbean, Tonga (South Pacific), Hawaii and in the Cheapeake Bay (Maryland) - it works! If you don't have a current copy of Chapman's Book of Piloting, buy a copy and read it. If you already have it, read it again - great stuff. Happy sailing.
 
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R.W. Landau

Conditions

I have been on too many boats that dragged anchor. I would first not assume that conditions would not get worse. Next, I would not doubt that the wind may change direction. Next I would not assume that everyone else in the anchorage is securely anchored. And last I would make sure if the anchor dragged that there would be no drop-off (Say from 10' to 30'). First action is to check predicted weather. Different fronts will rotate the whole anchorage clockwise or counter clockwise. Second I would want to be the boat that is upwind of the others during the worst forcast wind. We were at the Elliot Island Regatta in Biscayne bay one year and watched boat after boat drag anchor and tangle in the other boats and cause them to drag anchor as they were moved with the wind. Third, the anchor purchasing charts at your local marine store are base on 30 knot winds. Any low pressure front will blow well beyond 30 knots if only for a few minutes. Size your main anchor a few sizes to big. It is worth the money and peace of mind. Fourth, a chain atleast as long as your boat will help keep the correct angle of pull on the anchor. More chain is better but if you do not have the stretch of a nylon rode, you may still have problems. My choice would be about 1.5 times the boat length of chain and nylon rode. A 10 or 15 pound sentinal ( a mushroom anchor) at the chain to nylon rode connection will give you alot of holding power while keeping your scope at 7 to 1.( remember that that scope is calculated from the depth of the water plus the height of attachment to the boat, not just the water depth.) Fifth, I have been in anchorages that when you anchor the depth is 7' to 10' at the anchor but the boat is floating in 30'. If the boat drags anchor, your scope goes from 7 to 1 to 2 to 1. Yes you may think me crazy... when I am not the captian of the boat, I do not sleep. Every boat that I have been on has dragged anchor or turned into another boat with wind shifts at least once on every trip I have taken with someone else. You may think that I am crazy for these precautions but now I will not sleep unless these proceedures are figured. I now sleep quit well at night at anchor. r.w.landau
 
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David A. Hoyt

Chain Saves space

I installed a Simpson Lawrence windlass and 200' of chain with a Delta anchor and trip line with float. The float marks my anchor's position since with chain it can be in a far different location than a line rode anchor system. I can let out much less chain since I can slide a sentinental down the chain once the anchor is set and thereby minimize my scope. All in all it is a great system to use and allows me to anchor close to shore in tight areas where other boats with line rodes cannot anchor due to swing radius.
 
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Dan

pound of prevention

I always like to play it safe. I use anchors that are well into the safe weight rating for the boat ie: 35# Delta and 44# Bruce. Both are rated for winds to 42 kts based on my boat size. The primary has 150 ft rhode (all chain), the other has 50 ft chain and 150 ft nylon. For a backup I keep 60# Luke collapsed in a locker. It can be assembled in a few minutes and is rated for 60kt winds (I hope I never need it!) If the anchorage is tight I deploy both primary and secondary from the bow, one into the wind/current, and one opposing. This way I may wrap around once, or twice, but undoing the wrap is quick and easy. I have an electric windlass installed which makes retrieval somewhat less than a workout with Arnie.
 
Jul 1, 1998
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Hunter Legend 35 Poulsbo/Semiahmoo WA
Avoid Crowded Anchorages!

That may sound trite but that's what we do. In all the years we've lived in the Northwest, last year was the first time we "cruised" the San Juans and even then it was only for about 4 days. One of reasons is to avoid all the crazy and un-caring skippers throwing their wake around and another is to avoid the crowded anchorages. My guess is that Gary is asking this question because he goes to the San Juans and has experienced the anchoring problems. Am I right Gary??? One of the nice things about going where the others don't is you can do your own thing. 10:1 - Hey!, no problemo! On our Hunter Legend 35 we've got 375-ft of 5/8" Samson braid and 45-ft of 5/16-high test on a 35# Delta which is not too much. I had 3/8-BBB and when it comes time to replace the current chain I'm going back to the BBB (shackles fit much better). We've also got a collection of other ground tackle including mushroom anchor and a storm tackle system. Scope: I don't like to drag my rode on the bottom - you never know what's down there. On the other hand, I like lots of rode out so this is a real delima. I treat each anchoring situation differently and don't have a standard or pat one-way-fits-all approach. Stern tying in some places is sometimes a necessity because of lack of room and excessive water depth but wind and currents can make things messy so I only do this in settled conditions.
 
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Terry Lee

Scope

I have 26" of chain on a Danforth anchor At the end of the chain I have a 10" lb. ball which sets the anchor. You feel the anchor hit, then the ball. Then about 20' of scope. Good to go. The ball moves to leeward and sets the anchor. If the tide comes in the ball just changes angle and sets the anchor even better. I might let out another 10 feet of scope if rafted or not. depends on how heavy the boat (or boats are. I have a 25" Catalina so I'm usually the one rafting to the bigger boat. Terry Lee 360-491-7184
 
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Dave Dduelin

Two anchors

Aside from crowded anchorages, many times I have to anchor in the ICW with strong tides and restricted room to the sides. The ICW is narrow in many places, with the shore on one side and the channel on the other. Working commercial tow traffic moves in all weathers around the clock and I am very careful not to anchor in a manner that allows a swing near the channel or of course, onto the beach. I use a method that has already been described, that of two anchors set 180 degrees apart. There is almost always a current running one way or the other. I usually drop the first anchor up-current and set it at 7 to 1 or better. I then drift back twice that distance letting out bow rode until dropping the second anchor. If alone, I pull my way forward with the bow rode over-hand until in the middle of the two anchors. If I have crew, we motor up to the middle, carefully taking in excess bow rode, then set the second anchor with power. I use two scrap pieces of bronze as killicks. Tied to the rodes about 4 feet under the waterline, they keep the lazy rode from snagging the keel or rudder when she swings to the current or wind change. I use about 20 feet of chain to nylon rodes, a Bruce 22 as primary and a 22# Spade as secondary for my Morgan 30. I trust the Bruce on shorter scope, and often shorten to 3 or 4 to 1 scope after setting it with a minute or so of 75% rpm in reverse.
 
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Steve Bigelow

Anchoring in tight quarters

We've had great success with crowded ancorages over the years by using a weight along with our rope rode. I have two weights, one 6lbs, and one 10lbs. They are deployed after I anchor, set at 5 to 1 and then slid down the rode on its own lanyard attached to a caribiner. Works great, and you have no idea what a few pounds do to keep you settled in nice and tight when others are swinging and having problems with their neighbors.
 
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Mary E. Springhorn

There is scope and there is scope.

Whereas I love to anchor way out from the hoi-polloi and put out up to 1o:1 scope with my 40 pound Danforth, 100 feet of chain and 200 feet of nylon rode, I have to be realistic. In crowded anchorages one can't do this and not expect to become close "friends" with some of the charter boats in the anchorage. My solution, not unique, is to use a sentinel. I have a 30 pound "Kiwi" anchor rider that increases the catenary of my rode and allows me to anchor securely with less scope, in crowded anchorages. I highly recommend this. Mary E. Springhorn, PARALLAX, P424 Hull #61
 
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Gord May

Scope & Technique

Some good advice to be culled from these postings, to which I’ll add a few cautionary comments: - Bahamian Mooring should set the two bow anchors at something slightly LESS than 180 degrees (160-170). - Sentinel Weights (kellets, rode riders) should be suspended between two thirds to three quarters down from surface to bottom, so that it remains suspended in all but absolutely calm conditions. - Reversing under power simulates only about 20 knots of wind (for most auxiliary sailboats), so don’t assume (absolutely) that 3000 RPM in reverse, for a minute has “set” your anchor for any conditions. - Watch your neighboring boats’ swinging circles. You have to adapt your methods to fit in to the established pattern, understanding that (even in a “blow”) not all boats will ‘lay to’ in the same direction. - Most boaters carry anchors (and tackle) that are TOO SMALL, for any but the most benign conditions. (Ie: I deployed 35# Delta & FX23 Fortress on a 28.5', 6,900# C&C29) - No anchor will hold until “set”. Take your time, reverse it in, deploy Sentinels, then “look” or “dive” your anchor(s). I know, it ain’t always easy - I sailed in Lake Superior, as well as the tropics. - The original question, on “Scope”? After stating the obvious (more is better), and agreeing /w the “authorities” that 7:1 is good (10:1 better & 5:1 often adequate) the question becomes a matter of practicality - how much room is there? If you cannot feel secure, you’ve got to move. Anchoring technique can be as important as scope. Good luck and regards, Gord
 
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Holly Pierce

Claustrophobia

Recently I was on a lake and had a spot picked out to anchor at and the next thing I knew I had some idiot in a pontoon come zooming in on my starboard side! I immediately had to go in reverse and get out of the cove. I knew how much space I had before I hit the other boats and this idiot took the only space I could be in. I'm so new at boating that I'd welcome any advice on how to handle rude boaters.
 
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Todd Alt

The Peaceful Anchorage

I use 30' of chain on 200' of cordage as a rode on a Bruce as my primary off the bow roller. I have the same rode on a Danforth as a secondary. I always try for 7:1. I rarely use the Danforth as I am worried about the two getting entangled, thus rendering both inadequate. I don't spend many nights at anchor anymore as I simply have no faith in my fellow boaters not to slam me, and the Lake likes to get choppy at night. Only on very calm days do we anchor in crowded areas for a day of swimming. I have found the best prevention for disaster is to dive down to see that my anchor has actually got a good hold on the bottom, and then I keep an eye on the other boats around me. The biggest threat to my comfort is the jet-skis and powerboats that have no respect for anyone at an anchorage. These boaters speed over anchor rodes (marked or not), and at times create incredible wake within the anchorage. They threaten the safety of anyone (including children) that may be in the water or sitting on a deck. I would say that these people should read a safe boating publication or take a course, but I am convinced that they don't read anything other than the label on their booze bottles. Lake Erie is a large lake, but it is hard to find a nice place to anchor that some hillbilly with a giant Searay and more money than brains can't unload his jetski riding offspring for a day of terrorizing other boaters. I guess it is obvious that I recently experienced a rough day at the swimming hole.
 
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Paul

To all you 2-anchor types...

You think that you're solving the crowded anchorage problem with two anchors. Guess again. When I pick out a spot in a crowded anchorage, I am assuming that you, in the boat(s) closest to me are swinging on 7:1 scope, unless I can clearly see chain. Then I figure 5:1. I also try to imagine where we'll all wind up in a 90 degree or 180 degree shift. A common practice that I happen to use myself is to pull up behind another boat, drop my anchor two lengths or so from that boat, and then drift away to 5:1. If you're sitting on a bahamian moor (2 anchors off the bow) and there's no way I can see that, then you--yes you--are going to be in the way when the wind shifts significantly. I'm going to bump into you in the middle of the night, and when I come up half asleep I am not going to be impressed with your brilliant anchoring job. Bow-stern anchors and bahamian moorings are great for squeezing into a geographically tight anchorages--creeks and coves--not for carving out a too-small spot for yourself in a crowd. Crowded anchorages count on everyone swinging together. Just my opinion, Paul sv Escape Artist h336
 
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