If you want to use both a bow and stern anchor to keep your boat from dragging due to light winds or overnight shifts, do you use the same size and type of anchors and same rules of thumb for scope for both anchors? Which do you set first? How do you retrieve them?
bow and stern anchors
- Thread starter Bill C320 Papillon
- Start date
- Status
Either row it out with the dink
or ease back on the bow anchor rode as far as you can (set first), drop the stern and then pull up on the bow again, and then set the stern either by hand or with the motor slow ahead till it bites. Don't over do it!
or ease back on the bow anchor rode as far as you can (set first), drop the stern and then pull up on the bow again, and then set the stern either by hand or with the motor slow ahead till it bites. Don't over do it!
Why?
I don't understand why you would want to do this. You say "keep your boat from dragging due to light winds or overnight shifts." Why would the boat drag due to light winds? Why is a bow plus stern a solution to dragging, as opposed to two anchors at the bow?
I don't understand why you would want to do this. You say "keep your boat from dragging due to light winds or overnight shifts." Why would the boat drag due to light winds? Why is a bow plus stern a solution to dragging, as opposed to two anchors at the bow?
Bow and Stern
Traditionaly stern anchoring is used in tight harbors to prevent boats from swinging into each other. The biggest concern is to pay attention to the way others are anchored and then do the same. If you come into a cove or harbor and drop a stern anchor, when no one else does, you will have some fairly pissed off neighbors who will be swinging your way when the wind, tide or current shifts. The other time you would want a stern anchor is for wind that opposes a current to prevent swinging over the anchor constantly. A stern anchor is not to help you ride out a storm because in storms wind direction can shift quickly and a boat beam to the wind will have more load on the two anchors that it would on one bow anchor. If you want more holding power a Bahamian moor is a far better choice but in my estimation more chain and a better primary anchor is the best method. In 35+ years of sailing I have stern anchored maybe 50 times out of literally thousands of anchorings... If you want to keep your boat from dragging using a proper technique, which includes back winding the sails or using the motor in reverse at a high rate of throttle to set the anchor, and proper rode & setting technique will do far more with one anchor than doing the "Hollywood Toss" with two...
Traditionaly stern anchoring is used in tight harbors to prevent boats from swinging into each other. The biggest concern is to pay attention to the way others are anchored and then do the same. If you come into a cove or harbor and drop a stern anchor, when no one else does, you will have some fairly pissed off neighbors who will be swinging your way when the wind, tide or current shifts. The other time you would want a stern anchor is for wind that opposes a current to prevent swinging over the anchor constantly. A stern anchor is not to help you ride out a storm because in storms wind direction can shift quickly and a boat beam to the wind will have more load on the two anchors that it would on one bow anchor. If you want more holding power a Bahamian moor is a far better choice but in my estimation more chain and a better primary anchor is the best method. In 35+ years of sailing I have stern anchored maybe 50 times out of literally thousands of anchorings... If you want to keep your boat from dragging using a proper technique, which includes back winding the sails or using the motor in reverse at a high rate of throttle to set the anchor, and proper rode & setting technique will do far more with one anchor than doing the "Hollywood Toss" with two...
Hear! hear! to Maine Sail, but in further answer
to your question, my "stern anchor" is lighter than my primary bow anchor, namely 1/2 in 3-strand nylon instead of 9/16 in ; carries far less chain, and has a lighter anchor (22-lb Bruce vs 46-lb CQR). As Maine Sail said, it is used principally to keep the boat from swinging somewhere I don't want it to go in tight harbors or anchorages, or in some cases, to keep the boat more-or-less facing the swell when the wind dies at night (usually). Normally, in the tight anchorages I'm in, there might not be enough room to pay out the same scope as the bow anchor, unless you want the rode lying in a pile on the bottom, in which case it's not helping much! (Of course if the stern anchor is in much shallower water, the "scope" could be the same on much less rode out.) The best way to get one up in my (aching-back) opinion if you have room and depth to turn the boat, and if you don't have a stern anchor roller, is to recover the bow anchor by paying out the stern rode (if you have enough), then transfer the stern rode to the bow roller and haul it up (that's one reason to keep it light.) Otherwise, you're out in the dink doing it when it could be sloppy, or, as most probably do, hauling it up over the transom dinging up your gelcoat and wood! If the stern anchor is in shallow water, those may be the only options. BEO
to your question, my "stern anchor" is lighter than my primary bow anchor, namely 1/2 in 3-strand nylon instead of 9/16 in ; carries far less chain, and has a lighter anchor (22-lb Bruce vs 46-lb CQR). As Maine Sail said, it is used principally to keep the boat from swinging somewhere I don't want it to go in tight harbors or anchorages, or in some cases, to keep the boat more-or-less facing the swell when the wind dies at night (usually). Normally, in the tight anchorages I'm in, there might not be enough room to pay out the same scope as the bow anchor, unless you want the rode lying in a pile on the bottom, in which case it's not helping much! (Of course if the stern anchor is in much shallower water, the "scope" could be the same on much less rode out.) The best way to get one up in my (aching-back) opinion if you have room and depth to turn the boat, and if you don't have a stern anchor roller, is to recover the bow anchor by paying out the stern rode (if you have enough), then transfer the stern rode to the bow roller and haul it up (that's one reason to keep it light.) Otherwise, you're out in the dink doing it when it could be sloppy, or, as most probably do, hauling it up over the transom dinging up your gelcoat and wood! If the stern anchor is in shallow water, those may be the only options. BEO
I have dropped a stern anchor when the wind was
light but the powerboat wakes were many. With the bow pointed towards the channel and the bow anchor set I pay out a twenty to one scope and drop a northill 15 pounder on a couple of hundred feet of 1/2 with twenty feet of chain. Then as I pull in my bow rode I pay out my stern rode until I am about half way between and cleat the stern rode and take a light strain on the bow rode. The very light current hits me on the beam but doesn't hurt anything. The anchorage is crowded if there are five boats strung out along a half mile of shoreline.
light but the powerboat wakes were many. With the bow pointed towards the channel and the bow anchor set I pay out a twenty to one scope and drop a northill 15 pounder on a couple of hundred feet of 1/2 with twenty feet of chain. Then as I pull in my bow rode I pay out my stern rode until I am about half way between and cleat the stern rode and take a light strain on the bow rode. The very light current hits me on the beam but doesn't hurt anything. The anchorage is crowded if there are five boats strung out along a half mile of shoreline.
Stern anchor
I use one in two sets of conditions. One, if there is no wind it will stop the boat from drifting around and possibly getting tangled in the rode or drifting into a neighbor. It keeps the boat in one spot. I like to use a small anchor with maybe 2 to one rode so that if the wind does kick up, that stern anchor will drag and allow the boat to head into the wind. I also will use one, but with more rode, if I am worried my swing may take me aground.
I use one in two sets of conditions. One, if there is no wind it will stop the boat from drifting around and possibly getting tangled in the rode or drifting into a neighbor. It keeps the boat in one spot. I like to use a small anchor with maybe 2 to one rode so that if the wind does kick up, that stern anchor will drag and allow the boat to head into the wind. I also will use one, but with more rode, if I am worried my swing may take me aground.
Smaller
Maine Sail's response is comprehensive. I will add that if you do want to use a stern anchor, for the right reasons, then no you wouldn't normally need the same size as the boat's primary. Rode could also be compromised a little too, although you should try to keep scope consistent.
Maine Sail's response is comprehensive. I will add that if you do want to use a stern anchor, for the right reasons, then no you wouldn't normally need the same size as the boat's primary. Rode could also be compromised a little too, although you should try to keep scope consistent.
Tie to tree on shore
Bill if you are in Kansas you are lake sailing...at least there. Tying off to shore is preferrable to a stern anchor in many situations. In some lakes I can get real close to shore...in my old Macgregor I could often get close enough to tie to a tree without getting off of the boat. Just drop a bow anchor in deep water and then back into shore. Tie off and pull back out. Light and varible currents and winds can make a mess of anchor lines. I stopped using two anchors once I bought a 33# claw anchor that resets itself pretty well. During a storm in Andrew's bay near Panama city I drug two anchors the wind shift did it. The plow didn't reset and the danforth speared a conch and couldn't reset. Knock on wood, the Claw has always reset and has always held. Now I keep the Claw on the bow roller and the large danforth in the anchor locker. A lot depends upon the boat. My boat "sails" back and forth at anchor when there is much wind. The keel is large enough to cause problems with currents. I tried two anchors near Mobile Bay's entrance at Navy Cove. The current kept the boat broadside to the wind. So I put out a stern anchor. When the tide changed the boat spun around and wrapped the lines under the boat. Fortunately there wasn't any strong winds and one anchor held us in place. But next morning it was a pain getting the anchors up. Now unless I'm expecting major winds I just use the claw. If I expect major winds I use the claw and the danforth both on the bow. I leave enough slack so that if I'm hanging from one anchor the line on the other anchor will be deep enough to be below the keel and rudder.
Bill if you are in Kansas you are lake sailing...at least there. Tying off to shore is preferrable to a stern anchor in many situations. In some lakes I can get real close to shore...in my old Macgregor I could often get close enough to tie to a tree without getting off of the boat. Just drop a bow anchor in deep water and then back into shore. Tie off and pull back out. Light and varible currents and winds can make a mess of anchor lines. I stopped using two anchors once I bought a 33# claw anchor that resets itself pretty well. During a storm in Andrew's bay near Panama city I drug two anchors the wind shift did it. The plow didn't reset and the danforth speared a conch and couldn't reset. Knock on wood, the Claw has always reset and has always held. Now I keep the Claw on the bow roller and the large danforth in the anchor locker. A lot depends upon the boat. My boat "sails" back and forth at anchor when there is much wind. The keel is large enough to cause problems with currents. I tried two anchors near Mobile Bay's entrance at Navy Cove. The current kept the boat broadside to the wind. So I put out a stern anchor. When the tide changed the boat spun around and wrapped the lines under the boat. Fortunately there wasn't any strong winds and one anchor held us in place. But next morning it was a pain getting the anchors up. Now unless I'm expecting major winds I just use the claw. If I expect major winds I use the claw and the danforth both on the bow. I leave enough slack so that if I'm hanging from one anchor the line on the other anchor will be deep enough to be below the keel and rudder.
Why are you draggin in the first place?
I think you need to figure out why you are dragging in light winds, before start thinking about adding a stern anchor. What was your scope? If you don't have enough rode out, it will drag. Unless the bottom is hard to set, the easiest way to stop dragging is to increase scope. If there is no other boats nearby, go with 7-to-1.
I think you need to figure out why you are dragging in light winds, before start thinking about adding a stern anchor. What was your scope? If you don't have enough rode out, it will drag. Unless the bottom is hard to set, the easiest way to stop dragging is to increase scope. If there is no other boats nearby, go with 7-to-1.
JC and Moonsailer
Moonsailer, you seem to be the only one who noticed that I'm in Kansas and a lake sailer. I have and will continue to tie a stern line on shore and this works well however there are some places where I like to anchor that I can't get close enough to do that. Our anchorages are not crowded so swinging or not swinging into other boats is not a problem. JC, I haven't had a dragging problem yet but I like to sleep through the night without popping out into the cockpit every few hours to check. The reasons for potentially dragging in light winds are most notably--power boats and their wakes. In steady winds, the wakes won't swing me far enough to dislodge the anchor but with little on no wind, a power boat wake can send the boat back over the anchor and potentially pull it loose, in the same manner you would purposely retrieve an anchor. Maybe a stern anchor isn't the right insurance but that's why I asked the question.
Moonsailer, you seem to be the only one who noticed that I'm in Kansas and a lake sailer. I have and will continue to tie a stern line on shore and this works well however there are some places where I like to anchor that I can't get close enough to do that. Our anchorages are not crowded so swinging or not swinging into other boats is not a problem. JC, I haven't had a dragging problem yet but I like to sleep through the night without popping out into the cockpit every few hours to check. The reasons for potentially dragging in light winds are most notably--power boats and their wakes. In steady winds, the wakes won't swing me far enough to dislodge the anchor but with little on no wind, a power boat wake can send the boat back over the anchor and potentially pull it loose, in the same manner you would purposely retrieve an anchor. Maybe a stern anchor isn't the right insurance but that's why I asked the question.
I'd be amazed if...
a boat anchored with the right ground tackle and with proper scope on a light wind or windless night could have its anchor pulled out (considering the slack in the rode under light wind conditions) from the wake of a powerboat going by. You might have some needless worry here. BEO
a boat anchored with the right ground tackle and with proper scope on a light wind or windless night could have its anchor pulled out (considering the slack in the rode under light wind conditions) from the wake of a powerboat going by. You might have some needless worry here. BEO
Anchoring and tieing to shore
It is common in my cruising grounds in small anchorages that drop off at shore to anchor and tie to a tree on shore as you do. There are lots of undeveloped and public lands in our favourite cruising area so this doesn't interfere with property rights. Anchoring bow and stern is fine as long as it doesn't somehow interfere with people that are already in the anchorage swinging freely. In fact if most people use it you can anchor many more boats in the same space. In addition to having a good anchor of adequate size and a heavy chain lead, I have the following suggestions to help you feel secure: 1. Anchor from the stern and tie the bow to shore. This protects your rudder should you drag towards shore. 2. As Maine Sail said always SET YOUR ANCHOR using power. Start by letting out at least 5:1 to 7:1 scope and gently setting your anchor. As you see it grab the bottom gently apply more and more power while watching your bearings on shore objects. If you can see that you are moving ease off on power and give the anchor a chance to grab. If it won't set then move to another spot and try there. I usually take the power up to cruising rpm which is around 2200 to 2300 rpm. I have never dragged an anchor when set by this method and I have been anchored in winds above 60 knots. I have seen others drag many times and almost always it is because they didn't set their anchor using power. They just dropped it overboard and let the boat settle back on it. Another point - when I am anchoring with the bow tied to shore, I almost always let out lots of scope on the anchor - ie. 10:1 as I will not be swinging I do not have to worry about swinging into someone else. Lots of scope and at least 30 or 40 feet of heavy chain near the anchor allong with nylon anchor rode (line) helps to cushion the effect of waves. If you are really paranoid, you can put two anchors off the stern at 45 degree angles and a line to shore. It is however more complicated to set the second anchor using power. We used to have a boat with a bowsprit - we would put out two anchors off the stern and ease the bowsprit in over large rocks and tie off with two lines to trees on shore. The kids could then go ashore when they wanted by just steping off the bowsprit. At night we would ease the bow lines by 10 feet and take up the anchor lines. I agree with the rest of what Maine Sail said about anchor types and arrangments and there have been other good comments and suggestions in the thread.
It is common in my cruising grounds in small anchorages that drop off at shore to anchor and tie to a tree on shore as you do. There are lots of undeveloped and public lands in our favourite cruising area so this doesn't interfere with property rights. Anchoring bow and stern is fine as long as it doesn't somehow interfere with people that are already in the anchorage swinging freely. In fact if most people use it you can anchor many more boats in the same space. In addition to having a good anchor of adequate size and a heavy chain lead, I have the following suggestions to help you feel secure: 1. Anchor from the stern and tie the bow to shore. This protects your rudder should you drag towards shore. 2. As Maine Sail said always SET YOUR ANCHOR using power. Start by letting out at least 5:1 to 7:1 scope and gently setting your anchor. As you see it grab the bottom gently apply more and more power while watching your bearings on shore objects. If you can see that you are moving ease off on power and give the anchor a chance to grab. If it won't set then move to another spot and try there. I usually take the power up to cruising rpm which is around 2200 to 2300 rpm. I have never dragged an anchor when set by this method and I have been anchored in winds above 60 knots. I have seen others drag many times and almost always it is because they didn't set their anchor using power. They just dropped it overboard and let the boat settle back on it. Another point - when I am anchoring with the bow tied to shore, I almost always let out lots of scope on the anchor - ie. 10:1 as I will not be swinging I do not have to worry about swinging into someone else. Lots of scope and at least 30 or 40 feet of heavy chain near the anchor allong with nylon anchor rode (line) helps to cushion the effect of waves. If you are really paranoid, you can put two anchors off the stern at 45 degree angles and a line to shore. It is however more complicated to set the second anchor using power. We used to have a boat with a bowsprit - we would put out two anchors off the stern and ease the bowsprit in over large rocks and tie off with two lines to trees on shore. The kids could then go ashore when they wanted by just steping off the bowsprit. At night we would ease the bow lines by 10 feet and take up the anchor lines. I agree with the rest of what Maine Sail said about anchor types and arrangments and there have been other good comments and suggestions in the thread.
Bill: If you are worried, then increase your scope
If the wake from a passing powerboat might pull out your anchor, then you do not have enough rode. Increase it. A very safe scope is 7:1. Example, if you are in 20' or water, then let out a total of 140' of anchor chain/rope. In tighter quarters, go with 5:1. If real tight, I guess you could go with 3:1, but I wouldn't. I don't know what it is like to anchor at a lake. I sail in the Puget Sound, and we have current, wind, and especially tide. The tide will change the scope during the night.
If the wake from a passing powerboat might pull out your anchor, then you do not have enough rode. Increase it. A very safe scope is 7:1. Example, if you are in 20' or water, then let out a total of 140' of anchor chain/rope. In tighter quarters, go with 5:1. If real tight, I guess you could go with 3:1, but I wouldn't. I don't know what it is like to anchor at a lake. I sail in the Puget Sound, and we have current, wind, and especially tide. The tide will change the scope during the night.
Calculating Scope
Remember to add the height of your bowdeck to the water depth to calculate scope. In JC's example below, 20 feet of water and (let's say) five feet of distance from the water to the bowcleat means 25 feet of "depth" from the cleat to the mud. To arrive at a 7:1 scope, 175' of rode is required. In this situation, 140' of rode, cleated off at the bowcleat, gives you a much steeper 5.6:1 scope. The stern anchor needn't be as large as the bow anchor, because it's job is simply to stop the boat from swinging, not to fight wind and tide to the degree the bow anchor does. I carry a Danforth (good for a single-direction pull, as one would expect in a bow/stern anchor deployment, and light and easy to handle) on my stern rail ready for immediate deployment as my kedge. Because it doubles as a secondary bow anchor, it's sized as a bow anchor, but could easily be smaller if it were to be a dedicated kedge. Some will set their anchors at 7:1, then come up to a shorter scope, esp. in a nice thick muddy bottom. The rules of thumb for chain/nylon I've always read are 5:1 for normal duty, 7:1 for greater holding, but even at 5:1 I'm often on the biggest swing radius in the anchorage. Powerboaters in particular seem to lie to very short scope, but they're not always the only ones who don't seem to want to get their rode wet.
Remember to add the height of your bowdeck to the water depth to calculate scope. In JC's example below, 20 feet of water and (let's say) five feet of distance from the water to the bowcleat means 25 feet of "depth" from the cleat to the mud. To arrive at a 7:1 scope, 175' of rode is required. In this situation, 140' of rode, cleated off at the bowcleat, gives you a much steeper 5.6:1 scope. The stern anchor needn't be as large as the bow anchor, because it's job is simply to stop the boat from swinging, not to fight wind and tide to the degree the bow anchor does. I carry a Danforth (good for a single-direction pull, as one would expect in a bow/stern anchor deployment, and light and easy to handle) on my stern rail ready for immediate deployment as my kedge. Because it doubles as a secondary bow anchor, it's sized as a bow anchor, but could easily be smaller if it were to be a dedicated kedge. Some will set their anchors at 7:1, then come up to a shorter scope, esp. in a nice thick muddy bottom. The rules of thumb for chain/nylon I've always read are 5:1 for normal duty, 7:1 for greater holding, but even at 5:1 I'm often on the biggest swing radius in the anchorage. Powerboaters in particular seem to lie to very short scope, but they're not always the only ones who don't seem to want to get their rode wet.
Good point, Anchor Down
You are right, I was trying to use nice round numbers in the examples, and I forgot to add the distance from the boat's deck to the water line. Yes, I have also seen many boats with very short, or no scope. I've often seen boaters who will toss an anchor, and the second it hits bottom, they tie it off. They must think the purpose of an anchor is to hook onto a log or rock.
You are right, I was trying to use nice round numbers in the examples, and I forgot to add the distance from the boat's deck to the water line. Yes, I have also seen many boats with very short, or no scope. I've often seen boaters who will toss an anchor, and the second it hits bottom, they tie it off. They must think the purpose of an anchor is to hook onto a log or rock.
Understanding anchors helps
Most anchors on small boat like ours are designed to bury themselves in the mud or sand, unless you're using an anchor specific for rocky areas. The anchor buries itself faster and holds better if the angle of the tug on the anchor is mostly horizontal rather than vertical. Increasing scope (ratio of rode payed out over depth under the bow) increases the horizontal angle of the pull; short scope decreases it and tends, therefore, to pull the anchor more upward and thus out. The relative weight of the anchor is nearly an insignificant element in its holding power for our types of boats. I think people somehow believe that the anchor is holding, if it is on bottom, from its weight, and therefore do not understand the need for proper scope. BEO
Most anchors on small boat like ours are designed to bury themselves in the mud or sand, unless you're using an anchor specific for rocky areas. The anchor buries itself faster and holds better if the angle of the tug on the anchor is mostly horizontal rather than vertical. Increasing scope (ratio of rode payed out over depth under the bow) increases the horizontal angle of the pull; short scope decreases it and tends, therefore, to pull the anchor more upward and thus out. The relative weight of the anchor is nearly an insignificant element in its holding power for our types of boats. I think people somehow believe that the anchor is holding, if it is on bottom, from its weight, and therefore do not understand the need for proper scope. BEO
This becomes more important as you get into
shallow water. If half of the distance to the bottom is air and the water is only five feet deep. Paying out 35 feet only gives a 3.5:1 scope. But if the water is twenty feet deep then it doesn't matter quite so much.
shallow water. If half of the distance to the bottom is air and the water is only five feet deep. Paying out 35 feet only gives a 3.5:1 scope. But if the water is twenty feet deep then it doesn't matter quite so much.
- Status