We all know Chapman's suggests a minimum of 7:1 scope at anchor. But what do you really use? Given normal anchoring conditions where you sail, how does the wind and current, bottom and choice of anchors dictate your scope? Have you ever used less and experienced dragging? Or do you play it safe and use more than is called for? Share your anchoring techniques here, then vote in this week's Quick Quiz at the bottom of the home page.
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7:1
I usually use a 7:1 scope since the average depth is around 20ft and I have a 150ft, 1/2 inch nylon rode with a 6 ft. chain. It is a mud bottom and I use a Danforth 13 on a 28 ft. boat. I do , on occasion, have a dragging problem but that is because the anchor is hard to set for some reason. Once it sets, it is set. I don't think it is a scope issue but more of anchor issue.
I usually use a 7:1 scope since the average depth is around 20ft and I have a 150ft, 1/2 inch nylon rode with a 6 ft. chain. It is a mud bottom and I use a Danforth 13 on a 28 ft. boat. I do , on occasion, have a dragging problem but that is because the anchor is hard to set for some reason. Once it sets, it is set. I don't think it is a scope issue but more of anchor issue.
Sleeping vs. lunching
When we anchor overnight I use at least 7 to 1 but always worry that others around me use less, and as we spin for wind or tide change we'll foul each other. Have not gotten a good night sleep many times. When anchoring for lunch I use 4 or 5 to one in the sand around Cape Cod and we never drag.
When we anchor overnight I use at least 7 to 1 but always worry that others around me use less, and as we spin for wind or tide change we'll foul each other. Have not gotten a good night sleep many times. When anchoring for lunch I use 4 or 5 to one in the sand around Cape Cod and we never drag.
SCOPE
We NEVER put less than 7:1 scope under foot and when conditions warrant I've laid out up to 10:1 (mostly Chesapeake Bay w/ summer T-storms). Of course, I keep in mind what other boats have out for scope and how they are tending to their anchor. I'm not shy about asking a late arrival who anchors too close to move (politely of course!) BTW, I use a DELTA anchor w/ 20' of chain & 1/2" rode. I really think that scope is only one part of the anchoring "chain" (pun intended!) Like most things on a boat, preparation is key to anchoring and that includes setting of the anchor. UNLIKE any number of stink-potters we've watched (who throw their lunch hook as far as they can and then back down hard while dragging across the harbor with a perplexed look on their faces) we slowly lower the anchor over the bow and lay out approx. 3:1 scope before taking a bite at dead slow reverse. I then let out almost full scope before using the engine (again s l o w acceleration to 2000) to fully set. Haven't had an anchor drag in years despite some huge storms.
We NEVER put less than 7:1 scope under foot and when conditions warrant I've laid out up to 10:1 (mostly Chesapeake Bay w/ summer T-storms). Of course, I keep in mind what other boats have out for scope and how they are tending to their anchor. I'm not shy about asking a late arrival who anchors too close to move (politely of course!) BTW, I use a DELTA anchor w/ 20' of chain & 1/2" rode. I really think that scope is only one part of the anchoring "chain" (pun intended!) Like most things on a boat, preparation is key to anchoring and that includes setting of the anchor. UNLIKE any number of stink-potters we've watched (who throw their lunch hook as far as they can and then back down hard while dragging across the harbor with a perplexed look on their faces) we slowly lower the anchor over the bow and lay out approx. 3:1 scope before taking a bite at dead slow reverse. I then let out almost full scope before using the engine (again s l o w acceleration to 2000) to fully set. Haven't had an anchor drag in years despite some huge storms.
Scopamatic
You all saw my magic splicing tool, this question gave me an idea for a new invention. You know those wheels they use to measure length of line in feet before they charge you a fortune for it? Why not put one on the bow of your boat to measure how much line you've let out, for that matter it could be interfaced with a depth sounder and a digital readout could tell you when you are safe. I usually anchor in nor more than 10 to 12 feet of water in mud or sand bottoms (Napatree point in RI, Salt pond in B.I., Cuttyhunk Isle, etc.) Use a CQR 35 pounder for a 35 foot O'Day. Haven't dragged yet with it. I always use 7:1 scope and have markers in my line every 20 feet to make sure. Dave
You all saw my magic splicing tool, this question gave me an idea for a new invention. You know those wheels they use to measure length of line in feet before they charge you a fortune for it? Why not put one on the bow of your boat to measure how much line you've let out, for that matter it could be interfaced with a depth sounder and a digital readout could tell you when you are safe. I usually anchor in nor more than 10 to 12 feet of water in mud or sand bottoms (Napatree point in RI, Salt pond in B.I., Cuttyhunk Isle, etc.) Use a CQR 35 pounder for a 35 foot O'Day. Haven't dragged yet with it. I always use 7:1 scope and have markers in my line every 20 feet to make sure. Dave
5 or 6:1 with all chain rode
When I had a 30' Morgan I used 30' of chain plus line and a 35# CQR with 7:1 scope. If it was really going to blow, I would use up to 10:1. Now with my h40.5, I have all 5/16" chain with a 45# CQR and I use 5 or 6:1. I am always careful to set the anchor and back down hard afterward to be sure. I always sleep well except when I'm up at 2am to assist a neighbor with their fire drill. Rich
When I had a 30' Morgan I used 30' of chain plus line and a 35# CQR with 7:1 scope. If it was really going to blow, I would use up to 10:1. Now with my h40.5, I have all 5/16" chain with a 45# CQR and I use 5 or 6:1. I am always careful to set the anchor and back down hard afterward to be sure. I always sleep well except when I'm up at 2am to assist a neighbor with their fire drill. Rich
7 or 8:1 - chain/rode
Don't usually anchor overnight. When we have, we usually put out a little more considering I have mostly rode. LaDonna
Don't usually anchor overnight. When we have, we usually put out a little more considering I have mostly rode. LaDonna
7:1 = Crash into shore
This lake drops off really fast. If we anchor in 20 Ft. we are only 20 ft from shore, so this means the boat could end up about 120 ft on shore. If anchor about 150ft from shore, the depth is about 150-200 ft. I have about 20ft chain. Lost an anchor last week in a tree. Had to severe the line. But I would not let Mother nature win this anchor, as it came as original equipment on my 270. I upgraded my dive equipment ($400.00) bought a new anchor so I could anchor long enough to retrive the original anchor. ($120) and went below to a depth of 50 ft. and got her back. No drag on this one, this was the safest mooring I have had so far.
This lake drops off really fast. If we anchor in 20 Ft. we are only 20 ft from shore, so this means the boat could end up about 120 ft on shore. If anchor about 150ft from shore, the depth is about 150-200 ft. I have about 20ft chain. Lost an anchor last week in a tree. Had to severe the line. But I would not let Mother nature win this anchor, as it came as original equipment on my 270. I upgraded my dive equipment ($400.00) bought a new anchor so I could anchor long enough to retrive the original anchor. ($120) and went below to a depth of 50 ft. and got her back. No drag on this one, this was the safest mooring I have had so far.
Scope
This is a great question! So many variables: wind, sea and bottom conditions, rode choice, anchor design, proximity of other boats... We use typically use a 55# Delta, all chain rode and snubber, with 5:1 scope on our 40. A great resource: Earl Hinz "Complete Book of Anchoring and Mooring." Cheers!
This is a great question! So many variables: wind, sea and bottom conditions, rode choice, anchor design, proximity of other boats... We use typically use a 55# Delta, all chain rode and snubber, with 5:1 scope on our 40. A great resource: Earl Hinz "Complete Book of Anchoring and Mooring." Cheers!
Several factors...
First of all, here is another vote for Earl Hinz' book. It is required reading, in my opinion. Two important issues are type of anchor and depth. A Danforth, for example, looses almost all of its holding power on short scope, and may not even set. 7-1 scope is pretty well mandatory. A CQR fares a lot better in this regard. I don't know about a Delta, but a Bruce looses only a proportional amount of holding power. For example, it will hold about half at 3-1 scope as it does at 6-1. With regard to calculating loads on an anchor, an important factor is the surge load. Since this is distributed over the length of the chain or road, it becomes less of a factor in deep water. In other words, a ten foot wave is proportionately much less of a surge in fifty feet of water than a ten foot surge in twenty feet of water.Consequently, a smaller scope ratio will work in deeper water. Of course, chain lies much flatter along the sea bed than rode, up to a point at which it becomes as taught as line. Until that point, however, a chain rode needs much less scope to achieve the same pull angle as line. In practice, I use a storm anchor sized Bruce as a main anchor. This allows me to have acceptable holding power at short scope, if necessary. But, if a storm comes up, I need only to let out more rode for the anchor to gain its full holding power and function as a storm anchor. I seem to spend a lot of time anchoring in depths of between thirty and fifty-five feet, which helps. My goal is to generally have about 5-1 scope, but I will go with 3-1 on occasion, and sometimes go as high as 7-1 or 8-1 or a bit more. The bottom is generally good sand and I have gone as much as eighteen months between visits to a marina. I sleep well, and don't mind leaving the boat to herself during the day as this system seems to work pretty well. My observation of cruisers is that, for whatever reason, Europeans seem to use less scope, 3-1 or 4-1 being thought of as quite acceptable. On the other hand, they do seem to slide around quite a bit, particularly French and German boats. Sorry about that! I use 220 feet of 1/4 inch Hi-Tensile chain backed up by 300 feet of line. Used to be the recommended 1/2 inch, but 5/8 is much easier to handle and chafe resistant, if less stretchy. In uncrowded anchorages of thirty feet or deeper (plus four feet of freeboard), I will typically lay out all the chain plus a little less than the depth in line. My scope will be appropriate for whatever depth I am in (up to about 85 feet), I have a snubber already in place, the line never touches bottom, and I will let out as much line as I need in stormy conditions. We last dragged in 1986 (TOUCH WOOD!!!)
First of all, here is another vote for Earl Hinz' book. It is required reading, in my opinion. Two important issues are type of anchor and depth. A Danforth, for example, looses almost all of its holding power on short scope, and may not even set. 7-1 scope is pretty well mandatory. A CQR fares a lot better in this regard. I don't know about a Delta, but a Bruce looses only a proportional amount of holding power. For example, it will hold about half at 3-1 scope as it does at 6-1. With regard to calculating loads on an anchor, an important factor is the surge load. Since this is distributed over the length of the chain or road, it becomes less of a factor in deep water. In other words, a ten foot wave is proportionately much less of a surge in fifty feet of water than a ten foot surge in twenty feet of water.Consequently, a smaller scope ratio will work in deeper water. Of course, chain lies much flatter along the sea bed than rode, up to a point at which it becomes as taught as line. Until that point, however, a chain rode needs much less scope to achieve the same pull angle as line. In practice, I use a storm anchor sized Bruce as a main anchor. This allows me to have acceptable holding power at short scope, if necessary. But, if a storm comes up, I need only to let out more rode for the anchor to gain its full holding power and function as a storm anchor. I seem to spend a lot of time anchoring in depths of between thirty and fifty-five feet, which helps. My goal is to generally have about 5-1 scope, but I will go with 3-1 on occasion, and sometimes go as high as 7-1 or 8-1 or a bit more. The bottom is generally good sand and I have gone as much as eighteen months between visits to a marina. I sleep well, and don't mind leaving the boat to herself during the day as this system seems to work pretty well. My observation of cruisers is that, for whatever reason, Europeans seem to use less scope, 3-1 or 4-1 being thought of as quite acceptable. On the other hand, they do seem to slide around quite a bit, particularly French and German boats. Sorry about that! I use 220 feet of 1/4 inch Hi-Tensile chain backed up by 300 feet of line. Used to be the recommended 1/2 inch, but 5/8 is much easier to handle and chafe resistant, if less stretchy. In uncrowded anchorages of thirty feet or deeper (plus four feet of freeboard), I will typically lay out all the chain plus a little less than the depth in line. My scope will be appropriate for whatever depth I am in (up to about 85 feet), I have a snubber already in place, the line never touches bottom, and I will let out as much line as I need in stormy conditions. We last dragged in 1986 (TOUCH WOOD!!!)
7:1 plus
Spend most nights on board at anchor. Use a Bruce with a 7:1 scope. Find that the Hunter enjoys sailing so much.....it will spend hours sailing around the anchor!! Suspect that it might have something to do withthe high freeboard and wing keel. I have found that to reduce our swing in crowded anchorages, I attach a 10lb kellet (mushroom anchor) to the rode and lower it to the bottom on its own line once the anchor is set. This reduces the swing and adds additional weight to the rode when the wind gets up.
Spend most nights on board at anchor. Use a Bruce with a 7:1 scope. Find that the Hunter enjoys sailing so much.....it will spend hours sailing around the anchor!! Suspect that it might have something to do withthe high freeboard and wing keel. I have found that to reduce our swing in crowded anchorages, I attach a 10lb kellet (mushroom anchor) to the rode and lower it to the bottom on its own line once the anchor is set. This reduces the swing and adds additional weight to the rode when the wind gets up.
Up here in the frozen tundra
of Puget Sound, we frequently experience crowded anchorages with 50 foot depths. 7:1? Not a chance. We'd have 350' of rode out and cover the entire bay. We do have good mud up here, though; nice and sticky. most sailors I know use Bruce or Deltas with about 4:1. Works fine.
of Puget Sound, we frequently experience crowded anchorages with 50 foot depths. 7:1? Not a chance. We'd have 350' of rode out and cover the entire bay. We do have good mud up here, though; nice and sticky. most sailors I know use Bruce or Deltas with about 4:1. Works fine.
7:1 in Superior's sand
The Apostle Islands on Lake Superior have many outstanding, well-protected sand bottom anchorages. We always use 7:1 min with 15 feet of chain. However, what I have found is that the amount I let out is directly related to how well I sleep that night.
The Apostle Islands on Lake Superior have many outstanding, well-protected sand bottom anchorages. We always use 7:1 min with 15 feet of chain. However, what I have found is that the amount I let out is directly related to how well I sleep that night.
Phil, it's a lot easier ...
to use 7:1 scope if you anchor in only 8-10 feet of water!
I guess that's the benefit of being this far up the river. The tidal influence isn't too great and the current is constant so you can actually get purty darn close to shore. LaDonna
to use 7:1 scope if you anchor in only 8-10 feet of water!
I guess that's the benefit of being this far up the river. The tidal influence isn't too great and the current is constant so you can actually get purty darn close to shore. LaDonnaScope? Do you mean how much rope at the end of
anchor right? I don't know, I guess about as much as is needed for the anchor to get to the bottom. Typically I just throw that 14 lb danfurth over the side until I see the line go slack and then let out a few more feet then tie it off somewhere on the front of the boat. Right after that, I go to the back of the boat with the engine running and fire up the 110V blender with a"special" home brewed concoction that knock you off your butt. I then sit back and enjoy. I am usually fine when I am in an anchorage with my 1987 35' SeaRay. If I think I'm gonna have any problems , then I'll just make sure to be close to another boat . That way I can just tie up to whoever is closest. My boat doesn't look too bad, just a few gouges and scrapes along the way. Sometimes other boaters are not very freindly though, they give me funny looks and say things with a snotty attitude whenever I start drifting into their boats (what ever happened to the camaraderie between boaters ?!?) So when that happens I typically haul a** out of the area as fast as possible, back home where at least the dock employees *have* to help me get back into my slip.
anchor right? I don't know, I guess about as much as is needed for the anchor to get to the bottom. Typically I just throw that 14 lb danfurth over the side until I see the line go slack and then let out a few more feet then tie it off somewhere on the front of the boat. Right after that, I go to the back of the boat with the engine running and fire up the 110V blender with a"special" home brewed concoction that knock you off your butt. I then sit back and enjoy. I am usually fine when I am in an anchorage with my 1987 35' SeaRay. If I think I'm gonna have any problems , then I'll just make sure to be close to another boat . That way I can just tie up to whoever is closest. My boat doesn't look too bad, just a few gouges and scrapes along the way. Sometimes other boaters are not very freindly though, they give me funny looks and say things with a snotty attitude whenever I start drifting into their boats (what ever happened to the camaraderie between boaters ?!?) So when that happens I typically haul a** out of the area as fast as possible, back home where at least the dock employees *have* to help me get back into my slip.
Hey, Bubba, you're in good company!
There are lots of sailboaters who do the same thing! But heck, as long as you blend up enough of those frothy mixtures, who cares?! LaDonna
There are lots of sailboaters who do the same thing! But heck, as long as you blend up enough of those frothy mixtures, who cares?!
LaDonnaHey Bubba! Wondered when you would show up!
I've seen you out on the water numerous times! LMAO!
I've seen you out on the water numerous times! LMAO!
Gulf of Mexico Anchoring
Scope for overnight anchoring is about 6:1 in the shallow waters of the Gulf of Mexico off New Port Richey. If it's just a couple of hours anchored off the beach, I find 5:1 is sufficient.
Scope for overnight anchoring is about 6:1 in the shallow waters of the Gulf of Mexico off New Port Richey. If it's just a couple of hours anchored off the beach, I find 5:1 is sufficient.
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