The Real Scoop on Scope

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Gary Wyngarden

Sure, we all know the theory: Take a reading on your depth sounder; adjust for tidal range; add a couple of feet cuz your transducer is below the water line; add a few more feet for the freeboard at the bow roller; multiply the result by three for an all chain rode or by seven for a mixed chain/rope rode and voila, you know how much anchor line to put out. Problem is in most of the anchorages we frequent, if you put out that much scope, you'd be banging into other boats all night, because of the lack of swing room. Sooo, how much scope do you really put out? Do you have an all chain rode? What kind of anchor? Have you ever dragged? What happened?
 

Phil Herring

Alien
Mar 25, 1997
4,923
- - Bainbridge Island
NW anchoring

Up north here we have crowded and deep anchorages. 40-50' is common. I have never been in an anchorage here where 7 to 1 scope would have been comfortable. I have used all chain rode, 3-to-1 scope, and a Bruce anchor one size larger than the guidelines call for. Don't try that with a Danforth! I think the Bruce is an under rated anchor. Even though it doesn't have the pure holding power of a Danforth, our anchorages here are well protected and holding strength is not the issue. Setting and scope are. In our nice, thick mud/clay, 3 to 1 with a Bruce will work fine. Bruce's do tend to drag a little when they re-set, but I've never experienced any that was even noticable. Now, that said, this arrangement would not work in many of the world's anchorages, but it sure does work here.
 
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LaDonna Bubak - Catalina Owners

7 to 1

Here on the river, 9 times out of 10, you can anchor without worrying about anyone else. I don't anchor my boat too often (use it primarily for day sailing or we tie up to the myriad public docks on the river) but when we do, we usually let out about 7 to 1. I have about 20 feet of chain & then rode on a danforth. Man, that sucker sets like you wouldn't believe in the river muck! Now on Rob's boat, he has all chain on a big old bruce. He usually lets out 3 to 1 unless it's really blowing and there's plenty of room, then he'll let it out a bit. He doesn't really anchor on the river, it's usually up in Puget Sound. LaDonna
 
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Justin - O'day Owners' Web

7 to 1

I am currently using a danforth two sizes up from recommended on a boatlength (25') of chain and 5/8" line. I tend to anchor on uncrowded locations, so swinging room is not an issue. The winds shift from day to night in this area, however, and as a consequence the boat will often pull around 180 degrees. I like the long rode so that if it swings and gets a mediocre reset, I'm still ok. This winter, I will add a bow roller and Claw (Identical to Bruce; lots cheaper). It too will be oversized. I like to sleep well. Justin - O'day Owners' Web
 
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Tom Senator

Daytime 3 to 1 - Overnight 5 to 1(in average wind)

Overnight and wind/current picking up then I'll add a little more scope and/or I'll add an anchor sentinel (10lb lead weight dropped down 5/8" rode) with my new anchor -- 44lb Spade ps I just got my Spade anchor (44lb) and tested yesterday.( I have 20 feet of chain with 150 feet of 5/8" rode) -- INSTANT SET at 2.5 to 1 rode !! in 10 feet of water with 8-10 knots of wind . For more of a test, I then put out 5 more feet for total of 30 feet and backed down really hard and the boat did not move. (like it was stuck on a rock) This was probably all within just a couple of minutes so the anchor never even had a chance to really dig -- anchor never skipped out of bottom to reset.......So far so good !!! I'm happy - If I would have had my danforth it would have taken alot longer to feel like I got a good set and I would almost always need alot more rode . I know people love the danforth, but they take a while to set and you always need alot of rode - I hear if they have time to really set (day or 2) then they are good. Too many times its takes an extra set (or two) to get to them down though. If I really needed my anchor, right away (e.g. High winds & Lost power to engine) then I want my anchor to set instantly.
 
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Gary

Reasonable Scope

I had the same problem (35 ft Hunter) in the San Juan Islands and Gulf Islands this summer. The issue was the swing rather than the holding power. I had to be satisfied with a 4 to 5:1 scope with a Danforth and 50 ft chain plus 200 ft line. If I used a 7:1 scope, the max depth was only 30 ft at high tide and we have 10 ft tides which means I am looking for a 20 ft max depth at low tide. It was tough finding depths of 10-20 ft, so you end up in 35-40 ft depth with a 5:1 scope so you did not swing into your neighbor or the beach. I was also amazed at the number of boats in Deer Harbor that anchored very close to shore. They are assuming the only forces on their boats will be tidal and not wind.......which seems dangerous to me. I made it all the way to Desolation Sound this summer and stopped in Pender Harbour. There my anchor dragged on a tide change and it put me uncomfortably close to the shore. I have purchased a 33# Bruce instead of the 22# Danforth in hopes that will solve the dragging problem. Also I have been concerned about the anchor not resetting with a tide/wind change.
 

Phil Herring

Alien
Mar 25, 1997
4,923
- - Bainbridge Island
Gary: the big fallacy about Danforths

The thing people never talk about with Danforths is how tough it is to set them properly. Not that it's impossible, but lots of folks don't get it hooked. Almost all the dragging I've seen is with that anchor, rated among the leaders in holding power. :) Sure, in a storm I'd want one (used a Fortress as a second anchor) but for normal NW conditions give me a Bruce or Delta any day.
 
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Peggie Hall/Head Mistress

I use a Danforth...always have...

With a 3/4" all rope rode except for 6' of heavy chain between the rode and the anchor. Whether it's a "good" anchor or not depends on the bottom you're trying to anchor in. It does have to have something to "sink its teeth into," so it's not a particularly good choice on a rocky bottom, but you can't beat a Danforth in clay, mud or sand..and it's not THAT hard to set--.just back down on it as you feed the rode out slowly. If you just drop it, it'll fall over on its back every time...and it does force you to use at least a 3-1 scope (which is the minimum you should use anyway) to keep it lying flat so he flukes can stay dug in. 99% of the boats I've ever seen drag an anchor--Danforth or any other kind--do so for one or all of the following reasons: failed to put out enough scope neglected to back down on the anchor to set it never went back to check after they THOUGHT it down to make sure it really was.
 

Phil Herring

Alien
Mar 25, 1997
4,923
- - Bainbridge Island
Danforth continued

Hi Peggie, Here's my fourth reason to add to your three, and what I've seen numerous times with Danforth's: backing down too fast, setting anchor, then shutting down and springing forward from the rode tension, bouncing ahead of the anchor and pulling it out of the mud. Voila! No set. Of course, that can happen with any anchor, but it seems especially bad with danforths in my experience because they don't re-set as easily as a bruce or Delta. My 2 cents...
 
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Jim Covey

Sail Magazine article

There was an interesting article in Sail magazine last month "All About Anchoring". One new idea (to me anyway) is to have a rode with 2 lengths of chain seperated by 30' of heavy nylon line in between. The second chain length adds weight to get the rode flat with a shorter scope without having to use an all chain rode. The only caveat to the article is that the line between the chain needs to be extra large due to increased chafe from the bottom. Jim Covey
 
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Peggie Hall/Head Mistress

Got a funny anchoring story for you...

First, though, re re-setting a Danforth...there's only one way: raise it and start over. However, I'll vouch for their holding ability in the right bottom...mine held all day during a regatta when the winds were 35-gusting to 50+ last spring--AND on a short rode...I was in 60' of water and I only have 300' of anchor line The story... A friend and I were anchored (in her boat) in a shallow bay off the South River near Annopolis...we're firmly set and there for the night. Just about dark, while we're enjoying our after dinner coffee, here comes a sailboat....stops about 75 yards away from us and drops his anchor--literally...just drops it overboard and ties it off as soon as it hit bottom...and goes below for the night. A very slight breeze had come up... My friend looked at me and said, " the breeze is gonna send 'em right to us, so it looks like we'd better take turns checking their progress about every two hours...you wanna go first, or want me to?" Sure, 'nuff...every two hours they were another 20 yards closer to us...till finally about 5 am she woke me up and said, "grab a boat hook and put down fenders." They were abreast of us! So we just reeled 'em in, rafted 'em to us...and FINALLY got some sleep! About 8 o'clock we were havin' our first cup of coffee in the cockpit when our new neighbor's hatch open and a very sleepy head poked out It took him just a minute to figure out where he was...then his jaw dropped. We just grinned and said, "Good morning...want some coffee?" Not a word...he just disappeared back into his burrow like a groundhog on the 2nd of February...and in a minute scurried back on deck started his engine, and ran forward to raise his anchor (with only 6' of rode out, it didn't take long)...cast off our lines and skedaddled--without either he or his crew (wife?) ever saying single word to us...ever even LOOKED at us. I often wonder if he ever figured out that he'd have been aground in about 3' of water in another hour if we hadn't reeled him in.
 
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Tom Senator

Jim, an anchor Sentinel does the same thing.

That article is right the extra chain weight does help. But why go through all that hassle. I would just buy some sort of weight and hook it on the nylon rode and lower it down. here is a quick little article from Sailnet http://www.sailnet.com/collections/articles/index.cfm?articleid=woodto0060.
 
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Bob Camarena

Another Funny Story

I read this in a sailing magazine a while back. It may be the boating equivalent of an urban legend, but it's funny. It seems that this guy was scuba diving and came upon a man fishing from a small boat using a concrete-filled can for an anchor. Right next to his "anchor" was a fairly new Danforth or some other proper anchor that someone had lost. The diver cut off the can and tied the fisherman's rode to the proper anchor and swam off. He could only imagine what the fisherman's reaction was when he pulled up his anchor to go home.
 
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Gary

Dragging Danforth

I though I did everything right when my anchor dragged in Canada EXCEPT the scope of 7:1. Drop anchor, let out 120 ft of rode (scope 5:1 any more rode and I would have swinging problems), back off with engine in reverse for 30 seconds at 2000 RPM, no skipping, let out another 20 ft. In Canada you don't dive to check anchors like in Caribbean. Next morning I was too close to shore line for comfort. I think the scope increased as I got to shallower water. Discovered there was NO MUD on anchor when I retrieved it........charts did not mention rock or gravel. Prefer the heavier Bruce (33) over the Danforth (22). I am right on the borderline for weight now......no windlass with 33 lb anchor and 50 lb of chain. I can do it, but it is a workout.
 
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Peggie Hall/Head Mistress

Biggest mistake most people make

Is just dropping the anchor instead of SLOWLY backing down while feeding the line out. When an anchor goes straight down, it can fall over in any direction when it hits bottom...it's just luck if it falls over with the "teeth" or--in the case of Danforth, flukes--down. And if an anchor is on its back, it's not gonna set unless it snags something--which is another reason for backing down on any anchor to set it, but especially important with a Danforth. Danforths are pretty useless on a hard bottom, but once it's well and truly set in a soft bottom, it won't budge.
 
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marv otto

Then there's the time

I dropped anchor in a pretty bayou on the North Shore of Lake Pontchartrain. Lots of soft mud and the danfort does all things well. Did all the right stuff -- plenty of rode, back slowly, set, back some more. Perfect. Held fast for the night and most of the next day. Then a short but strong thunder storm broke and moved us a few feet. Better reset, I thought. Pulled up the anchor and about two hundred pounds of waterlogged branch. Drop branch. Circle to new spot and re-anchor. Holds well. Time to go home. Lift anchor. And the same two hundred pounds of waterlogged wood. Now if I had been trying to find that log a second time, could I have ever hooked it?
 
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Tom

How can a Danforth be "on its back"?

I thought the flukes on a Danforth flopped back and forth on either side of the shank. Tom
 
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Peggie Hall/Head Mistress

"On its back" maybe not the best way to put it

It'll fall on it's side or with the shank forward of the flukes--which means it can't dig in unless until/unless the weight of the boat against it pulls it back over. Backing down as you feed it out automatically accomplishes this...so does the wind--IF there's a strong enough breeze. But if you just drop it and play out scope without backing down on it, it'll just lie there on the bottom...it won't set.
 
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Les Andersen

Danforths, the sagas continue

Another Danforth problem is stopping the boat, letting the anchor down to the bottom, letting out some more rode, then backing down. The anchor generally lands straight up in the mud/muck and the chain drops down around the shank and jams in between the shank and flukes. When you back down the anchor drags sideways, backwards or whatever since the chain is effectively attached to the flukes that are jammed solid and cannot extend and grab anything. Then some not so nice words about Mr. Danforth's parentage and you pull it in and start over. If you lower it to the bottom as you back and then let out the scope it will generally lay out quite nicely on the first try and immediately dig in. I don't especially like them but they have always worked for me. Generally on the first try. Les s/v Mutual Fun
 
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Peggie Hall/Head Mistress

Les, if you just drop any anchor straight down...

and then pile rode on top of it before backing down, the odds are, the rode is gonna get tangled in the anchor. But as you pointed out, when you back down while lowering the anchor and paying out the rode, you have no trouble setting it.
 
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