Photos of Anchors Setting

[Factor]

Have you tried the Mantus without the roll bar, Greg from Mantus reckons you dont need it and it will work fine without it, it would good to try it without and give a perspective on that.
If it did work the same then one of my concerns - (roll bars) would be better managed.

[Cotemar]

Originally Posted by Factor

Have you tried the Mantus without the roll bar, Greg from Mantus reckons you dont need it and it will work fine without it, it would good to try it without and give a perspective on that.
If it did work the same then one of my concerns - (roll bars) would be better managed.

A Mantus anchor without the roll bar is ok for fishing or if you stay on the boat, but not recommended for over nigh or unattended boats.

[Factor]

Why, if its in and holding you for fishing or 3 hours, how would the roll bar presence matter.

[Cotemar]

Originally Posted by Factor

Why, if its in and holding you for fishing or 3 hours, how would the roll bar presence matter.

Set and reset for wind and current shift. Roll bar keeps the proper orientation, no mater which way the anchor is getting pulled from.

[Factor]

Not trying to have an argument here, but definitely not following you:

I understood Noelex to say that they reset without breaking out, and I can see now how that may very well be the case in the sort of barren sandy anchorages he is in, thus how would the roll bar matter? I can see how it matters for a set sometimes, though Greg from Mantus suggests that it really isn't needed? But once set, if it doesn't break out, how then would it matter? In fact - I suspect (without any evidential basis at all to support my suspicion) that the absence of the roll bar might in fact help in its ability to not break out?

This is what Mantus says on their Farce Book page

We have had some people ask if our anchor works just as well without the roll-bar - some boat's bowsprits are incompatible with roll bar type anchors. Although we sailed with a Mantus prototype for about a year without roll-bar & without any problems, we wanted data that was a little more quantifiable. We threw the 12lb Mantus off the bow right-side-up, up-side-down, sideways - it didn't matter - it always righted itself before resting on bottom. Check out the loopy-loop starting at 45 sec.

[Cotemar]

Factor,
I guess we will not know for sure until someone starts taking pictures of the Mantus with the roll bar removed on a set and re-set. Maybe if Noelex is in a location with few boats around him, he can give it a go. Would be great to see it happen in the real world anchorage.

[noelex 77]

Originally Posted by Factor

Have you tried the Mantus without the roll bar, Greg from Mantus reckons you dont need it and it will work fine without it, it would good to try it without and give a perspective on that.
If it did work the same then one of my concerns - (roll bars) would be better managed.

I know on your Seawind roll bar anchors do not fit as well.

I hope to be able to give it a try, but it's not a high priority.

The roll bar is right at the back of the fluke which is the last part of the anchor to bury so the roll bar does not hit the substrate until the anchor has already set well. If you look at my photographs the roll bar is only a few inches below the substrate so it's had minimal impact.

The angle of the fluke ensures the toe is long way down. Some quick calculations indicate that on my oversized anchor the tip is almost 0.5 m (over 1.5 feet) under the substrate if the sand is up to the top of the fluke. At this stage the whole of the rest of the anchor is buried, but only the first couple of inches of the roll bar are below the surface.

There will be a difference in the COG without the roll bar, but as this bar is quite thin and lightweight on the Mantus, I think the difference will be minor.

In short, I think it going to be very hard to see much change on most occasions without the roll bar. The exception is that without the roll bar if the anchor lands upside down it will of course never set. It has so far landed upright on every drop, but it would be absolutely essential to check the set on every occasion without the roll bar. I do this anyway, but not everyone does, and those that do don't always realise they are going backwards with an unset anchor.

[downunder]

Nolex,

I am hoping to see some photos of rollbar anchors completely buried.
At present we are always seeing the rollbar.

Does this mean that

1. They don't fully dive.
2. They are oversized and the vessels don't have enough power to set them but they will if we get strong winds.
3. The subscrate will not allow burying.

I know I would be happier if they did bury completely.

[JPA Cate]

Noelex:

Beautiful pic of your wife! Well done!

Ann

[noelex 77]

Originally Posted by downunder

Nolex,

I am hoping to see some photos of rollbar anchors completely buried.
At present we are always seeing the rollbar.

The roll bar makes these anchors taller.

In the photos I am showing the substrate is near the top of the shank. Once the shank disappears non roll bar anchors are no longer visible, but on these anchors the higher roll bar at the back of the shank can still be seen.

The anchor will continue to dive while the force is greater than the holding power. I have seen the top my Rocna roll bar a couple feet under but it takes strong wind and a soft substrate to require this depth of penetration.

The Mantus roll bar is taller than the Rocna so it will be seen for longer. It will take a lot of force and/or a soft substrate to require the roll bar to disappear. The top of fluke would need to be 10 inches under the substrate for this to happen, but I expect I will see this in the right wrong conditions.

[noelex 77]

Still at the same anchorage. It is a deserted spot so unfortunately there have been no other anchors to photograph.

Early this morning we had another sudden wind shift of about 120 degrees. That put some rocks right behind our stern and I needed to shorten the scope to 3:1 to gain just adequate clearance.

The wind is predicted to swing back 180 degrees around midnight and there are no quiet anchorages nearby that have reasonable protection from both wind directions, so we have elected to stay put.
The wind is only light to moderate, but it keeps jumping up as thunderstorms pass close. There is some wave action which is always tough on anchors.

This is an example where even in only light to moderate conditions you need faith in your anchoring gear. An anchor that lets go would leave no time before the boat was on the rocks.

Here is a photo of the anchor showing it rotated about 20 degrees remaining set and beautifully level even though the chain is leading off at 90 degrees (the worse direction to induce a list during rotation). Many anchors develop the rather unsettling habit of sticking one fluke high up in the air in similar conditions. The Rocna was very good at developing only a slight list during rotation, but I am starting to conclude the Mantus is even a little bit better. Perhaps the very wide base to the rear of the fluke is helping keep the anchor very stable?

If you look closely at the chain you can see it is just starting to lift within a few feet of the shank so while we still have catenary keeping the pull at the shank horizontal there is not much left.

The second photo is of my naked mistress's bottom with the rocks rising behind.

These are only normal anchoring conditions, but I guess the message is that even in moderate winds there are times (such as when the anchor is rotating, the rocks are close behind, and the scope is only short) when an oversized new generation anchor that you have confidence in is not overkill. Wait to when we get to serious conditions!

[noelex 77]

There are two methods of setting the anchor

1. Slowly reverse, or let the wind blow you back. When you reach your desired scope the load is taken of the windless (with a snubber, or chain stopper) and the reverse thrust is slowly increased starting just at idle reverse and ending up with high revs in reverse for a reasonable length of time (I stop after 30 sec in full reverse). Monitor transits, the rode, and or the GPS to make sure you are not moving backwards.

2. Reverse, laying out the chain. Allow the boat to build up a bit a speed in reverse, but make sure you are laying out chain quick enough so at this stage no load is on the anchor. This is normally done by releasing the windlass clutch so the chain free falls out. When the desired scope is reached and the windlass clutch is tightened the boat continues backward until the chain is pulled tight. The momentum of the boat sets the anchor. A good set is indicated by the chain suddenly going tight (and staying tight). The nose of the boat swings around into the wind, dips down (it almost looks like the boat is curtsying to a well set anchor ) and the boat comes to an abrupt stop. The boat will start to move forward as the weight of the chain sinks and this can be repeated if needed.
Lots of people do this, but if I am using this technique I prefer to use a chain stopper or to attach a short snubber (you need to be very quick). This takes the sudden load of the winch.

I nearly always use the first method. The slow build up of force is the best way to set the anchor. It is controllable and repeatable. You get a feel for how long the anchor takes to dig in and importantly if the anchor is slowly slipping backwards through the substrate. The second method can also be a bit dangerous if you misjudge it. If the boat builds up too much momentum (especially if you don't use the windlass clutch) the boat can come to a sudden stop and rip cleats out of the deck etc. This is especially true of the concave roll bar anchors (like the Mantus) and the Spade. These anchors usually set in 1-2 m. It is safer with the convex plough anchors (like the Kobra) which typically take a longer distance to set (2-6 m).

Anyway, I thought I would give the second method a try with the Mantus. The sudden force is a good test on the anchor in a firmer bottom. Many anchors will not set at all in a more difficult substrate with this sudden force. It also simulates the emergency use of the anchor. In an emergency (like a rope around the prop) when the current is pushing you towards a hazard you drop the anchor when the boat has some speed, hoping it will set.

The left photo shows the result of doing this with the Mantus. The substrate has a very light covering of weed, but this so light it would have little impact. The anchor was set at 4:1 in 9.4 m of water.

We certainly came to an abrupt stop. You can see the anchor set in 0.5m or less. An excellent result for such a sudden set.
The anchor has dug in immediately, but not set quite enough to be acceptable for overnight. You can see the anchor has not yet rotated level with a 20 degree list and there is still about 1/4 of the fluke area and all of the shank exposed. The anchor has done nothing wrong. It just means that next time I should use a bit more momentum, or repeat the sudden stop a couple of times.

In the end after seeing the result I elected to finish off the set by applying steady reverse and the right photo shows the final set. You can see it has dug in better, but only moved a few inches further back. This is typical of top class anchor. These will dig in at a very steep angle, getting deeper while barely moving backwards. A very steep "glide angle" to use an aviation term. Poor quality anchors dig in at very shallow angle often moving back metres and only digging in an extra couple of inches.

The final result is still not quite as good as the excellent sets the Mantus has achieved up to now. There is still a slight list, the shank is 1/2-3/4 buried and there is still a small amount of the fluke exposed. I would judge this an OK rather than excellent set. It is likely the substrate is a bit firmer rather than the different setting technique having an effect. I would expect with a bit more force from wind the anchor will dig in deeper. Importantly the anchor has set sufficiently that it will shuffle around to a new wind direction without breaking out.

We have still been alone in all these anchorages, but hopefully soon I will be able to show you some more results for comparison.

[DoubleWhisky]

Originally Posted by downunder

Noelex,

I am hoping to see some photos of rollbar anchors completely buried.
At present we are always seeing the rollbar.

Does this mean that

1. They don't fully dive.
2. They are oversized and the vessels don't have enough power to set them but they will if we get strong winds.
3. The subscrate will not allow burying.

I know I would be happier if they did bury completely.

Hi, downunder

Please note that anchors Noelex use are on large side for the boat.
His yacht is a little shorter than our and I suppose also somewhat lighter. We have 40 kg Rocna, one being in accordance with the manufacturer's sizing chart. Noelex use 55 kg Rocna and now even heavier Mantus. They are really "storm anchors" for this size of the boat. Their fluke area is great and I assume they are not diving more deep under average conditions just because of friction. The sand in the area where Noelex is at present (Dodecanese) is pretty hard and tight.
Sorry, I never took a pictures of our anchor on the bottom (we even do not have an equipement to do so), but I was always checking the set visually, when possible (from surface or diving).
Under the power (3.000 revs, Yanmar 160 hp, solid propeller) our Rocna sets well, but with the rollbar visible. Most of the time we were Med moored, so the anchor was under much higher load for all the time, if compared to anchoring out situation. By average after 24 hours the rollbar was invisible. After several days (about the week) it was not unusual to see the chain disappearing five or six metres before anchor position. It meant some work to take the anchor up, of course, by going forward and back over the place (to the fun of box of scoffers on the shore).
I assume the rollbar can cause a clogging in really thick weeds (less so for big sizes of anchor, with rollbars of proportionally large diameter - we had not the anchor clogged yet), can make retrieval from deep dive more difficult, but surely does not prevent anchor from diving deep into the bottom. What can stop the dive, is a layer of chalk, volcanic tuff, hard clay, tightly packed gravel or regular rock under the layer of sand - all not uncommon in Med, but it is a different story

Cheers,

Tomasz

[noelex 77]

A new anchorage. Finally another boat, with a different anchor to photograph . (See next post)

I wanted to anchor upwind of a boat that was already in the anchorage so in practice we ended up in quite different substrates.

The Mantus set in a remarkably short distance. It has not rotated completely level and a small amount of the fluke is showing. It is an OK (rather than excellent) set. I am confident with more force it would continue to bury and rotate completely level.
(8.4 m water 5:1 scope)

[noelex 77]

The Delta is in a different sort of substrate. I did not see it drop (the boat was already there when I arrived), but the long scope was estimated at 8:1 in 5 m of water.

The Delta has produced an acceptable set.
It has not rotated level and a reasonable amount of one fluke is exposed.
You can see how the convex plough style of anchor nearly always takes much longer to set that the concave designs.

The trench that is dug during setting should become deeper as you get closer to the anchor. If you look at the trench dug by the Delta it appears to get deeper then becomes shallower as the anchor hits a patch of weed then deeper again after the patch of weed. This suggests the anchor has partially "hopped" over the patch of weed. The weed is only very sparse and thin and the anchor should have cut through this sort of weed without any concern.

In defence it was a reasonably small anchor and I did not see the set, but if you look closely these sort of details of anchor behaviour do give an indication of anchor performance even when the end result is acceptable.