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Old 08-08-2007
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Learning to anchor

I can't seem to get my boat to stay where I put it.

The boat is a Cal 27. It's about 5,200 pounds or so.

The anchor is a 14 pound (or maybe 13 pound) Super Hooker Anchor. It's Danforth-ish. I've got 10 feet of 3/16" chain followed by 100 feet of 3/8" line.

I'm in a lake and the bottom is thick mud for the most part.

The worst case of dragging anchor was during an unexpected storm. We had anchored for the night and were sleeping. The winds came up to perhaps 15 - 17 knots and pushed the boat right along. I got it stopped by dropping a second anchor.

Most recently we had stopped for a swim. I don't think the anchor actually set this time because when I pulled it up it was not muddy. The wind was only about 3-5 knots. We held for a bit, but then started slowly drifting.

Whether I anchor off the stern or the bow doesn't seem to matter. I typically use about 4:1 scope and anchor in 15 feet of water. I stop the boat, drop the anchor to the bottom, then back the boat down until what I deem to be the appropriate amount of line is out, then hold the line until the boat stops (this is my attempt to set the anchor). If I can move the boat by pulling on the anchor rode I assume I've set the anchor and I cleat the line off.

I'm generally torn as to whether I should be more concerned about the general wind direction when I anchor, or with the general wake direction. I've finally decided that I need to anchor in such a way that both are pushing me in the same direction.

Is my problem the wrong anchor or poor skills or a combination?

Thanks,

Matt
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Old 08-08-2007
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Umm... 4:1 scope is a bit low for that anchor...especially with a mainly rope rode. If you're in 15' of water, and figure you have about 2' between the bow roller and the water, you'd probably want at least 120' of rode out, which you haven't got. That would give you 7:1 scope (7*17 =119).

With an all-chain rode, you might get away with scope as short as 3:1, but more typically you'd be at 5:1 and you'd want more scope than that for heavy weather. With a combination chain-rope rode, you really want 7:1 as a minimum if you can, and in a storm situation you'd probably want more like 10:1 or so.

Unless you set that anchor, it is likely to just be sitting on the bottom, waiting for the wind to pick up and let you drift off. Also, when you set the anchor, do you just dump all the rode overboard or do you lower the anchor and then back down, laying the rode out? If you just dump all the rode overboard with the anchor and don't back down while doing it... you'll have a nice tidy pile of anchor, chain and rope sitting on the bottom that will do little if anything to hold your boat. Also, once the scope has been paid out, do you slowly back down on the anchor rode to set the anchor in to the bottom, slowly increasing the power applied??

IMHO, part of the problem is poor anchoring technique. Part of the problem is the anchor itself. BTW, just because you can pull on the rode and move the boat doesn't mean the anchor is set. Friction between the bottom and the anchor could easily be enough to allow you to do that, but would do nothing if the wind picks up. Moving a boat through the water, especially at very low speed, like you would see via pulling on a rope, doesn't take all that much force.

Finally, Danforth-type anchors tend to be really bad at dealing with shifting winds or currents. A boat wake shouldn't bother a properly set anchor at all, but even a weak current that shifts can dislodge one that isn't properly set.

A newer, next-generation anchor would probably be far easier for you to set. A Rocna, Buegel , Spade, Manson Supreme or Bulwagga are ones you might want to look at.

BTW, IMHO, the anchor rode you've got is a bit on the light side. 3/8" three-strand nylon has a tensile strength of about 4400 lbs. Given that you should be using rode with a 5:1 or higher safety factor, that means your SWL is only about 800 lbs. That is really a bit low...but on a small inland lake might be okay. If your lake is a bigger one... and this is a really relative and subjective description, you would probably want to move up to at least to a 1/2" anchor rode... My lunch hook or kedge anchor is a 14 lb. Danforth with 10' of 1/4" chain and 100' of 1/2" rope. My primary anchor is a 33 lb. Rocna with 30' of 5/16" chain and 200' of 5/8" rope. I wouldn't use the Danforth to anchor out for a night...
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Last edited by sailingdog; 08-08-2007 at 09:29 AM.
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Old 08-08-2007
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mw...I think you have the wrong anchor AND a technique that could be improved. 100 ft. of line in 15' or less of water is plenty for an inland lake and 10 ft. of chain is also enough.
I would suggest that with a really soft mud bottom, you need an anchor that is designed for that and a Danforth knock off is not the answer. I would recommend a Fortress anchor with the flukes set at the 45 degree position for soft mud.
http://www.fortressanchors.com/fortr...hor_guide.html
the right model for your boat is the FX16 which you can get here on sailnet for under $200.
http://shop.sailnet.com/product_info...words=fortress

Note that fortress makes a cheaper guardian line of anchors but these do not have the 45 degree fluke adjustment which you need.
I agree with Dawg that your line should be 1/2 inch...but on a lake and in winds of 30 knots or less, this is probably not a big issue. I would certainly make sure it is in good condition and upgrade to 1/2 inch when you can.

As far as technique goes...you want to pay out your anchor line slowly as the boat backs away due to the wind. Snub it a bit as you get to about 1/3 of your intended scope to get the anchor flukes to bite...this should bring your bow back into the wind and in line with you anchor & rode. Then let out the remainder of your intended schope...5:1 is sufficient unless you are expecting really heavy weather...and snub the anchor.
In soft mud you then want to back down on the anchor using you motor SLOWLY until the anchor line is taut and you are sure it is holding...then give it some gas to make sure it isn't going to pop out if the wind picks up.
That's how to set in soft mud.

I would note that if there is no wind in your anchorage as you drop the hook...you need to use your engine to back down as you are letting out the rode...especially with fluke type anchors, you don't want a pile of rode on the bottom fouling your anchor as you try to set it or worse, fouling it when the wind pops up.

Hope that is helpful.
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Quote:
Originally Posted by sailingdog View Post
Umm... 4:1 scope is a bit low for that anchor...especially with a mainly rope rode. If you're in 15' of water, and figure you have about 2' between the bow roller and the water, you'd probably want at least 120' of rode out, which you haven't got. That would give you 7:1 scope (7*17 =119).
I believe you, but I never see anyone playing out that much line here. Although, I don't personally know too many sailors, either. More scope can't hurt, and I'll certainly try. I'll get more line.

Quote:
Originally Posted by sailingdog View Post
. . . Also, when you set the anchor, do you just dump all the rode overboard or do you lower the anchor and then back down, laying the rode out? . . . Also, once the scope has been paid out, do you slowly back down on the anchor rode to set the anchor in to the bottom, slowly increasing the power applied??
It never occurred to me to just dump line over the side. Typically, I'll be on the bow with my wife at the helm. I'll drop the anchor until it hits bottom, then call to her to back up. While the boat is backing I play out more line.

As to the second part of your question - I don't ever apply power after I think I've set the anchor. Should I? Sequence of events should be drop anchor to bottom, reverse the boat while playing out the proper amount of line, stop reversing, tie off line, then reverse again?

Quote:
Originally Posted by sailingdog View Post
IMHO, part of the problem is poor anchoring technique. Part of the problem is the anchor itself. BTW, just because you can pull on the rode and move the boat doesn't mean the anchor is set. Friction between the bottom and the anchor could easily be enough to allow you to do that, but would do nothing if the wind picks up. Moving a boat through the water, especially at very low speed, like you would see via pulling on a rope, doesn't take all that much force.
I'll work on my technique and I'll see about a new anchor. The latter may take a while as I'm budget constrained, but I'll put it on my list.


Thanks much for your help.
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Cam, great stuff. Thanks. I'll practice.

One point of clarification and a follow up related question. The mud isn't what I'd call soft. The "soil" around here is hard clay. The lake is just a dammed river over the same stuff. The mud is thick clay-mud.

Does that change your anchor recommendation any?
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FWIW, I am also in lake (just north of you if you are at Lanier) with the same type of bottom. I have used a 22lb Delta anchor for a Catalina 27 for a while and it has never failed to hold, even when a T-storm blows through. The anchor is a little large per recommendations, but I go along with the wisdom I have seen here that says if everyone is making fun of how big your anchor is, it's in the ballpark. I know when the wind has picked up, I have never said to myself "I sure wish I had a smaller anchor"...

Ryan
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Old 08-08-2007
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I'll second (third?) the info given above. You need more scope, and you need to consider the drop from your bow roller to the water when figuring out how much rode to let out. You need a different anchor.

And yes, after your anchor is down, all your scope is out, and you think it's set, power yourself up in reverse. This will do two things - completely set most anchors, and also confirm your holding in higher winds. The higher my expectation for wind speed, or the longer we anticipate being at anchor, the higher the revs and the longer I keep it powered up for (overnight, I'll go to somewhere around 2/3 cruising revs for 5-7 seconds). I also like to wait 15-30 minutes after setting anchor to verify that we're not dragging. My wife and I do a little exercise - I lean against the mast and site something on shore relative to a shroud. She lets me know if the boat is swinging at all (which would make the boat appear to be dragging when it's not). We do this 2-3 times over the 15-30 minute timeframe.
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Quote:
Originally Posted by mwrohde View Post
I believe you, but I never see anyone playing out that much line here. Although, I don't personally know too many sailors, either. More scope can't hurt, and I'll certainly try. I'll get more line.

It never occurred to me to just dump line over the side. Typically, I'll be on the bow with my wife at the helm. I'll drop the anchor until it hits bottom, then call to her to back up. While the boat is backing I play out more line.
Unfortunately, there are more people out there that don't know how to anchor properly, than there are that do... I've seen powerboats and charter sailboats do just what I described...and then they wonder why they dragged during the night.


Quote:
As to the second part of your question - I don't ever apply power after I think I've set the anchor. Should I? Sequence of events should be drop anchor to bottom, reverse the boat while playing out the proper amount of line, stop reversing, tie off line, then reverse again?
You don't necessarily need to reverse the boat while paying out the rode. If there is any wind, it will often back the boat down for you. Using the engine to set the anchor is never a bad idea IMHO. In soft mud conditions, you'd probably want to set it before letting out all the rode as Cam has suggested.

Quote:
I'll work on my technique and I'll see about a new anchor. The latter may take a while as I'm budget constrained, but I'll put it on my list.

Thanks much for your help.
Try looking at craigslist, as they've often got anchors and boat-related gear listed. As for what kind of anchor, I'd still recommend the same, and think that the next gen anchors will probably set in hard clay better than a Fortress. The Fortress is an excellent mud/sand anchor, but not as versatile as the ones I listed, and generally not as well suited to shifting winds/currents IMHO.

One other thing... just because you're on an inland lake, don't underestimate the size anchor you'll need. People laughing at the size of the anchor you're using is usually a good indicator that it is either about right or really way too small. Some inland lakes aren't really going to see rough conditions. I have a lake near my home that is maybe 1/2" mile across... and it won't see any rough conditions, even in really bad weather. Lake Winnepausakee, up in New Hampshire, on the other hand is more like an inland fresh water sea, with no tides. But in bad weather, you can see some serious waves and wind. I don't know what lake you're sailing on, but going a bit oversized is generally not a bad idea... and if you get a bigger boat and sail on salt water later on, you can always use it as a kedge or lunch hook on that boat.
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You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
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Last edited by sailingdog; 08-08-2007 at 11:11 AM.
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Old 08-08-2007
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Thanks so much, y'all. I already feel like I'll do better next time, even with the anchor I've got. I'll submit a new anchor to the budgeting committee and get it in the plan. Long list of boat stuff to get, and it seems to always get longer no matter how much stuff I buy.

Ryan, I am on Lanier. Where are you?
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I would suggest as many have said before using atleast a 7:1 scope and in a storm you would want atleast a 10:1 scope. Also I would suggest using a heavier anchor, not very much more but 14 pounds seems light to me for a 27 foot vessel.

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