Mantus has drug twice / Removable semi-permanent mooring?

[SKMT]

I've been on an 85lb mantus for about 2000 consecutive days. For the first 4 years it never once drug. Then twice in the same month it drug when a florida pop up storm ripped thru from the west (opposite of prevailing wind). Fortunately both times I was on the boat. Both times it drug at least 100-200 yards before I threw the back up (35lb HT danforth), which stopped the boat instantly. Both times the mantus came up without anything stuck to it or any chain wrapped (altho possible it unwrapped when raising with windlass from flybridge). 99.9% sucess rate is great for many things, but I need to keep my boat off the rocks 100% of the time.

I have a 44ft / 30,000lb trawler. What would be the best anchor for a triple anchor mooring? I most definitely would trust 3 Mantus', but is there any reason to shell out that much money for this application? I know danforths suck for a primary, but they are supposed to be top notch holding as long as they dont have to reset. If danforth is the anchor of choice, should I go with a Standard or Hi Tensile? Otherwise let me know any better option....

[carstenb]

I have no experience with Danforth. We do have a 69 lbs mantus for our (fully loaded 12 ton monohull. I might question if you 85lbs is big enough? We also have anchored >2000 nights in all parts of the world and have only dragged once (our own fault, Fatu Hiva - terrible holding, thin sand over sheet of inclined rock).

What was the substrate like where you dragged? Were you backed down hard on the anchor?

I just find it difficult to comprehend that your mantus would drag and not reset unless the substrate were something like rock or even very loose coral chips

Not much help from, I'm afraid.

cheers

[SKMT]

It's good holding bottom. "Difficult to comprehend"? It's a top notch anchor, but it's not infallable.

85lb is already considered oversized for my boat. Weight is not the problem. If the wind comes suddenly from 180 degrees opposite of set, I believe it can get flipped directly backward and then drug without recatching.

[carstenb]

Originally Posted by SKMT

IIf the wind comes suddenly from 180 degrees opposite of set, I believe it can get flipped directly backward and then drug without recatching.

Certainly possible, but generally the rollbar will ensure that the anchor tips to one side or the other, causing ti to start resetting.

But you are , of course, correct - nothing is infallible

[rslifkin]

Originally Posted by carstenb

Certainly possible, but generally the rollbar will ensure that the anchor tips to one side or the other, causing ti to start resetting.

But you are , of course, correct - nothing is infallible

The most likely time for a failure in that reset scenario is if it happens violently enough to pop the anchor completely out of the bottom (rather than rotating in place). Depending on the bottom composition, you can end up with a mud ball with chain sticking out rather than an anchor. When that happens the anchor won't reliably re-set, as it's not longer of a shape and weight distribution that can orient properly and dig into the bottom.

[Kettlewell]

If creating a two-anchor or star pattern mooring with two or three anchors Danforths or Fortress anchors are great. The Danforth Hi-Tensile version is the one you want. Any anchor can get fouled and it has happened to me a couple of times with my Mantus when the chain caught under the bolt holding one end of the hoop. It could happen if you sit on one anchor for a long time with the chain lazily wrapping around and around the anchor. When sitting for a very long time in one place I like to use at least two, and preferably three anchors for this reason, particularly if I will not be on the boat for awhile.

[Bmorgan562]

Originally Posted by SKMT

I've been on an 85lb mantus for about 2000 consecutive days. For the first 4 years it never once drug. Then twice in the same month it drug when a florida pop up storm ripped thru from the west (opposite of prevailing wind). Fortunately both times I was on the boat. Both times it drug at least 100-200 yards before I threw the back up (35lb HT danforth), which stopped the boat instantly. Both times the mantus came up without anything stuck to it or any chain wrapped (altho possible it unwrapped when raising with windlass from flybridge). 99.9% sucess rate is great for many things, but I need to keep my boat off the rocks 100% of the time.

I have a 44ft / 30,000lb trawler. What would be the best anchor for a triple anchor mooring? I most definitely would trust 3 Mantus', but is there any reason to shell out that much money for this application? I know danforths suck for a primary, but they are supposed to be top notch holding as long as they dont have to reset. If danforth is the anchor of choice, should I go with a Standard or Hi Tensile? Otherwise let me know any better option....

Im a newbie, but you didn't mention the amount /type /size of your rode..

[Off Trail]

Despite generally excellent performance in some very challenging situations, we have had 2 failures with our Mantus over the years. The first was as rslifkin describes: a sharp/rapid 180 degree reversal. We were in thick Key West weed/mud. The anchor flipper/popped and would not reset. When we raised it, the blade was encased in a thick mud ball, preventing the tip from engaging.

The other was a failure to set (in good bottom) so did not cause any problems other than a repeat set attempt. It was caused by chain wrap during the drop; see attached pic. This kind of situation may have been what you encountered.

I don't think there is any anchor that is completely immune from these kind of problems when deployed singly (certainly not a danforth/fortress which is highly susceptible to wrap if pulled backwards). So if your want bombproof, I would go with a multiple-anchor mooring setup. But for a single anchor I have thought about going with a design like Sarca or Spade which have a cleaner profile when it comes to chain catching of the anchor, also may be less susceptible to clogging. I think the protruding bolts of the Mantus are a flaw when it comes to wrap.

-Dan

[Off Trail]

I just realized I got carried away on the Mantus topic, and didn't give an opinion to the OP :-)

By all accounts, 3 Danforths in a triangle make a very good mooring. Probably three of any appropriately-sized anchors would do the same. Standard practice before the advent of screw moorings used to be large mushrooms which are excellent in soft bottoms, so that may be another option.

[Boatwright]

Originally Posted by Off Trail

I just realized I got carried away on the Mantus topic, and didn't give an opinion to the OP :-)

By all accounts, 3 Danforths in a triangle make a very good mooring. Probably three of any appropriately-sized anchors would do the same. Standard practice before the advent of screw moorings used to be large mushrooms which are excellent in soft bottoms, so that may be another option.

Our club has used the 3 Danforth triangle configuration in the mooring field for many years. Sailboats up to 35' and 8 tons. We are exposed to often strong northerly winds with long fetch down Grand Traverse Bay on Lake Michigan. Our fleet can be seen rocking and rolling with no problems. We also have variable winds from all directions, so the fleet is often meandering around in circles around the mooring balls.

Chain through the balls are required. We also have a diver inspect the bottom tackle twice a year. We do have the advantage of excellent sandy bottom holding. The Danforths end up completely buried with only the chain visible.

One advantage of the triangle set-up is that that the anchor(s) not feeling the pull act as kettles, keeping the loaded chain close to the bottom.

BTW: I have yet to hear of any anchor that will reset unattended 100% of the time -- too many ways to get tipped and/or fouled.

[sv Stella Maris]

Happy Friday All,

For the sake of my back, I agree and personally use Danforth-style “Guardian” anchors for such occasions and spare ground tackle. My older 60’ cat is at anchor 100% of the time we are aboard in the Antilles, her primary anchor is a Mantus 125# w/ 12mm chain. Boat is 23tons loaded, with massive windage.

Same as above, our Mantus “fails” are confined to hard/inclined bottoms, or the previously mentioned “Warp-Wrap” as I call it when training newbies. The official word form Mantus is to keep a bit of line in the primary shackle slot to disallow excess play, so the shackle is less inclined to flip-back on itself. Also like above, I have dumped chain too quickly on the Mantus and fowled it from the get-go.

My backup FX-23 holds amazingly well in soft stuff.

[SKMT]

If it's a long term mooring, what are opinions on aluminum vs galvanized? The weight is of no concern, as it will be rarely raised. Normally I would not pay the big bucks for the fortress, but I spy a gigantic used fortress, selling for the same price as a smaller danforth retails.

So corrosion is literally the only factor to consider. Should I be concerned about sinking an aluminum anchor on galvanized chain semi-permanently?

[CarlF]

The Danforth style anchor (including the newer Fotress/Guardian) are incredibly reliable as long as you have plenty of scope and the pull is in one direction. The Danforth was invented and first used for the D-Day landing. It was dropped from the stern of the landing craft before they hit the beach and then a winch could pull the landing craft back out to get the next load.

I own two Fortress anchors (primary anchor is a 100lb Spade). I believe they dig in more reliably and hold better than the Danforth. They also can be easily disassembled for storage. Mine are 20 years old and have gone with me from boat to boat. When you sell a boat the buyer only asks about the primary anchor.

As long as the pull is one direction and you have plenty of scope they are incredibly reliable. And in muddy bottoms they do better than that the new anchor designs. I would carry them simply as my mud bottom anchor.

I carry two Fortresses (a 15lb FX23 AND A 35lb FX55). I use the smaller one to take out in the dinghy to set as a kedge anchor to keep the boat from swining into a shoal in a tight harbor. The big one gets set for heavy weather. If the bottom is known to be soupy mud I'll often set the FX55 as the only anchor.

[SKMT]

Also wondering about dislodging a fluke anchor if it has been set for a couple years. Is the design vulnerable to bending or breaking if deeply buried and powering in opposite direction is needed to break loose?

[sailorboy1]

I personally don't feel a danforth being much better than a mantus in the same conditions once properly set