What's the best anchor type for mud bottom lake?

[dsteele1]

I've finally experienced the "Honey, why is that boat honking it's horn" while we were both in the cabin while anchored in a mud bottom lake in a nice secluded cove in 25 mph winds. :wow::wow::wow:

Went topside to find we had dragged anchor about 500 feet and got within 10 feet of the shore. Luckily we didn't snap off the stern drive or hit bottom. :smt101:smt101:smt013

We have the standard delta style anchor that Sea ray provides and it has worked fairly well in the mud bottom - that was until we experienced the 25 mph winds yesterday.

So what do you guys suggest? I have a bruce style 2nd anchor but that doesn't seem to do any better. I do have a 6' chain I haven't used yet... :huh: :smt100

P.S. I forgot to mention that we got hit by monster 1 foot waves while in the cabin from I suspect a 48 Sundancer that went by the cove. The swim platform was smacking the water and the bow lifted a good foot or two which probably popped the anchor out of the mud. I was too busy trying to get the 12VDC outlet in the cabin to make a consistent connection to the power supply for my laptop to realize what was going on topside.

 

[coolings]

West Marine recommends a Fortress anchor. The broader the fluke, the better your chances of penetrating through the mud. As the winds increase, you will need more scope. The added scope and the chain should help your anchor set. It will need to get through to the bottom of the mud to set and be able to hold your boat in those condition.

 

[fc3]

A delta should hold well enough, as this test shows. How much scope did you have out? How did you measure the scope? Wild guess, based on the typical boaters I've witness is that you didn't let out enough scope.

Best regards,
Frank

 

[tmhudson2]

If the winds were only 25mph, and there was no appreciable current pulling on your boat, just about any anchor of proper size (and I assume the one that came with your boat was adequate size) should have held if there was enough scope. I would have had 7:1 scope out in that situation at a minimum, unless I had a length of chain as the section of rode attached to the anchor. I've got 25' of chain on mine, but that may be overkill here on the lake.

 

[Sundancer]

After you let the anchor out did you set it to make sure it would hold by backing down? I'd definitely add some chain, at least 20 - 25 feet to help the anchor stay put and transfer the load to a nearly sideways pull instead of an upwards force towards the boat. That will help it dig in.

 

[Southpaw II]

Chain makes all the difference in the world....6' will help, but 15' is better. You'll be good in up to 30' of water, with enough scope. I've tried achoring with/without chain, and it's like night and day.

 

[wingless]

The factory plow anchor w/ factory 200' 5/16" chain worked okay, at best. I would use 5:1 in crowded areas and 10:1 when space permits.

When I changed to a Fortress FX-37 it was like night and day.

With the factory anchor the best I could do was bury it up to the shackle. With the Fortress I didn't hit the mantle, but it is never a problem to bury the anchor plus 10' of chain into the crust.

One time I was ashore when the wind picked up, big-time. I was the farthest in the anchorage. As the launch approached, the second-to-last guy identified his boat and said why is that guy against him, when I peered out into the rain I saw it was me.

Long story short, he was upwind from me, when the wind picked up his anchor let go, he scooted along until he snagged my chain rode and my trusty FX-37 held us both in a nasty wind. When I was pulling up my chain his anchor was hooked on to my rode. He finally stopped compaining it was my fault when I tossed his anchor near his yacht.

The only new issue is pulling it out. I'd retract until the scope is vertical and wait for wave action to work the anchor free. Sometimes its a long wait.

The image shows the deck plate I added w/ a concealed coiled hose for the raw-water bow washdown. A through-hull, seacock, strainer and pump were added to feed this hose. I wired the pump feed to the windlass, through its own breaker, so it would only run when the windlass is powered.

The washdown is handy w/ all-chain, 'cause every bit of crud on the bottom, ends up in the anchor locker, so forget about keeping the drains clean. Plus, I never worry about running out of water.

 

[chuck1]

Why does you anchor not sit right in the roller?

 

[wingless]

This image shows the red / white / blue color code I painted every 20" on my rode.

There is no problem seeing this from the helm to determine the scope, from the deployed rode, the depth gauge, knowing my pulpit elevation and the tide chart.

 

[wingless]

Why does you anchor not sit right in the roller?

The flukes touch the hull using the factory pulpit, so I flip 'em up.

 

[fc3]

Why does you anchor not sit right in the roller?

Because he's using the wrong style anchor roller. He's using a roller for a plow style anchor, not a danforth style. It's a half-assed mod.

Best regards,
Frank

 

[wingless]

It's a half-assed mod.

Best regards,
Frank

Nice! Best regards right back atcha.

 

[wingless]

Because he's using the wrong style anchor roller. He's using a roller for a plow style anchor, not a danforth style.

The FX-37 is one size greater than recommended for the size boat. It fits okay, with the chines down, in the factory pulpit, but just touches. The smaller recommended anchor might fit w/o changes, w/ the chines down.

My usage requires the larger anchor. As sunset I use 760 hp of backwash to slow the planet's rotation to extend the sunset duration.

All the Danforth style pulpits I found were too wide for the flat space on the deck. I was unwilling to change the deck glass and I was unwilling to decrease strength by adding a spacer underneath the pulpit to make that fit.

 

[dsteele1]

A delta should hold well enough, as this test shows. How much scope did you have out? How did you measure the scope? Wild guess, based on the typical boaters I've witness is that you didn't let out enough scope.

Best regards,
Frank

Scope was 5 to 1 in 9 feet off water = ~50 feet. Couldn't go much longer as the cove is narrow (about 150 feet) and the boat ALWAYS sways back and forth sideways, slowly about 40 feet. Why does it do that? You'd think it would just pull downwind. :huh:

 

[fc3]

Scope was 5 to 1 in 9 feet off water = ~50 feet. Couldn't go much longer as the cove is narrow (about 150 feet) and the boat ALWAYS sways back and forth sideways, slowly about 40 feet. Why does it do that? You'd think it would just pull downwind. :huh:

You didn't have enough anchor line scope. 9 feet of water under the depth sounder + 2 feet from the surface to the transducer + 3 feet from the anchor roller to the surface = 14 feet. You had a scope of about 3.5:1. Should have been more like 85 feet of line for a 6:1 scope. Soft mud is soft. Either the anchor digs though to the underlaying harder surface and holds, or it slowly pulls. More scope give it a better chance to dig in. Remember that digging in also requires more scope since the anchor will (hopefully) bury itself a couple of feet into the mud.

The boat shifts side to side because of turbulence, varying wind speeds and angle, elasticity of the anchor rode and other factors. Though the wind and current seems steady, it is not. It constantly changes which moves the boat about. While the boat and wind shift, the boat also "rubber bands" against the anchor line, which adds it's own effect to the motion by storing and releasing energy. Don't have enough space to explain in detail. The physical world is not strictly newtonian where you can draw simple force vectors and place a system in perfect, motionless equilibrium. You need to go into chaos theory.

Or ask Gary. Either one.

Best regards,
Frank

 

[dsteele1]

You didn't have enough anchor line scope. 9 feet of water under the depth sounder + 2 feet from the surface to the transducer + 3 feet from the anchor roller to the surface = 14 feet. You had a scope of about 3.5:1. Should have been more like 85 feet of line for a 6:1 scope. Soft mud is soft. Either the anchor digs though to the underlaying harder surface and holds, or it slowly pulls. More scope give it a better chance to dig in. Remember that digging in also requires more scope since the anchor will (hopefully) bury itself a couple of feet into the mud.

The boat shifts side to side because of turbulence, varying wind speeds and angle, elasticity of the anchor rode and other factors. Though the wind and current seems steady, it is not. It constantly changes which moves the boat about. While the boat and wind shift, the boat also "rubber bands" against the anchor line, which adds it's own effect to the motion by storing and releasing energy. Don't have enough space to explain in detail. The physical world is not strictly newtonian where you can draw simple force vectors and place a system in perfect, motionless equilibrium. You need to go into chaos theory.

Or ask Gary. Either one.

Best regards,
Frank

Very nicely explained :smt038 I'll bet the anchor chain will help to bury and set the plow also. :thumbsup: I vote for the chaos theory. :grin:

 

[Southpaw II]

Simpler just to use some chain. Requires less scope, less mods, and fewer posts......

 

[Four Suns]

Scope was 5 to 1 in 9 feet off water = ~50 feet. Couldn't go much longer as the cove is narrow (about 150 feet) and the boat ALWAYS sways back and forth sideways, slowly about 40 feet. Why does it do that? You'd think it would just pull downwind. :huh:

Sometimes bigger and uglier on the anchor is not the answer (and sometimes ugly squared).

The boat swinging like a pendulum on the hook is caused by the boat sailing upwind. I drew a little diagram on my Mac here for you:

The turbulence around the boat will orient the boat with a side to the wind at some point which will begin a process where the boat will literally sail upwind until the anchor line pulls the nose over into the wind enough and then the boat rotates and sails back the other direction basically repeating the process over and over like a big pendulum on a grandfather clock. If you have a bridge boat, the problem is worse. If you have an aerodynamic body like a sailboat, the problem is worse.

The fix is to use an anchor snubber or anchor bridal where it hooks on a side cleat up by the bow:

When the boat tries to rotate to start sailing upwind, the force is transferred to the side cleat to rotate the boat back into the wind so it won't sail.

I didn't draw this picture but this is what it looks like:

You can buy them... or make one.. I made mine...

A boat swinging in the wind like this can introduce several hundred pounds of additional force on the anchor (and not in-line with the anchor) and break just about any anchor free if the wind is strong enough and the boat is working in perfect harmony. Also, the longer you make the anchor rode, the worse the swinging becomes.

Another option, which is essentially shortening the rode but keeping the anchor line at the correct angle to the sea floor is to put anchor rode weights on the rode itself. I've never done that but know sailors that do... That also helps the swinging.

I have an all chain rode and have a horrible swinging problem if I don't use a snubber on the front. One time I ducked into a cove to avoid a squall with 60 knot winds in it and the boat was swinging so bad I almost went into a sea wall after dragging probably 500-600 feet. Some boats did hit the wall... I was lucky that day. I didn't have time to put the bridal on... and something about holding on the front of the rail with an anchor hitting ground and lightning all over the place made me jumpy.

 

[Converse48]

Great explanation of this Gary. My Carver 36 Sedan had a flat bottom, all chain rode and a LOT of windage (did I mention it was a Carver?). As such, when the boat was sailing off in one direction as it neared the end (it was probably up to 3-4 knots) you could hear the chain rattle as the slack was running out. This would then be followed by a loud "bang" as the slack ended and the boat would "come about" over to the other tack. And so on and so on.

Try to sleep through that and one will quickly learn the benefits of the bridle.

 

[Four Suns]

There is also an easier way to measure how much rode you are putting out if you have a windlass. The windlass specs should have how fast the thing deploys the anchor line so all you have to do is figure how many seconds you have to let the line out for the length you want and it should be close enough for government work. If the specs don't have it, run the thing for 5 seconds and measure the line that comes out... mark it down and put it by your control at the helm.

That is unless you like having your chain painted up like a victory rock in front of a high school.