Lagoon 450 + Mantus Anchors + bolts

[Scout 30]

We finally retired our CQR for a Rocna Vulcan a couple of weeks ago. I think it's a good alternative, especially if the length of the shank is an problem.

New: The Vulcan®. | Rocna Anchors // Rock Solid

[evm1024]

Stainless Bolts on stainless anchors, Galvanized on galvanized.

As a side note the assembly instructions call for tightening up the lubricated bolts to just past when the split washers compress.

As a test I looked up the torque specs for lubricated galvanized bolts (of the correct size) and then tightened up to the specified torque. It turns out that at proper torque they just compress the split washers.

[SpiritBear]

Originally Posted by mresman

Yes - I thought that as well. Maybe blue (might want to take them apart without a blowtorch). But, what about underwater? Will the Loctite maintain its integrity?

Lock washers and proper torquing works well in many environments. But, soaking in saltwater for potentially days at a time?

I just purchased a Mantus 65 + Mantus swivel for my 42-foot Grand Banks trawler here in Seattle. (Yes, I'm a sailor in skill and heart but there are reasons why my 1975 GB was the best choice when I bought her). The Mantus comes with fairly massive bolts and a packet of waterproof axle grease that they instruct you to smear all over the bolts before installing and tightening them down.

So, Loctite? An anchor isn't subject to vibration of any consequence, so probably not required at all. With the threads greased up pretty well you'll get a huge amount of effective torque on the bolts because it's not a dry fit that could bind up. The lock washer ensures that the nut won't back off. Give it a solid amount of tightening and it'll never come loose unless you apply a lot more force in the opposite direction. I have no worries about this being a weakness.

My anchor chain, on the other hand is kind of rusty crap. That's either going to be re-galvanized or replaced before cruising season here in the Pacific Northwest.

[noelex 77]

I don't think you should be concerned about the bolts. The ability to store the anchor flat is great feature. I removed ours recently after about 750 nights at anchor and they just as tight as when first installed. If you are worried It is easy to visually check if the bolts are coming loose by simply looking as the anchor comes over the bow roller. The bolt head is underneath so the amount of thread sticking out above the nut on the top of fluke provides an indication of the bolts' tightness. If one of the four bolts on the shank/fluke did become loose (which I think is unlikely) Mantus claim that a single bolt is strong enough to carry the force so there is plenty of reserve.

Loctite is recommended by anchor swivel manufacturers, but these are often constructed so that the loss of a single bolt would detach the chain from the anchor. Also, the bolts on the swivels usually do not have any locking mechanism such as the split washers that are present on the Mantus anchor.

So Loctite could be used on the Mantus bolts, but is not necessary in my view. If it helps your peace of mind I don't see any real drawbacks. It is easy to use big spanners on the bolts or even some heat , so you should still be able to remove the bolts in future even if you use the strongest grade of Loctite. If not, it is no different 95% anchors with a fixed attachment between the shank and fluke .

[geekoman]

Great replies everyone. Thank you.

[montenido]

I put a 105# Mantus on my Californian 52CPMY. That is one big anchor. When it sets under power, I have to warn guests so that they don't spill their sundowners! Since the water is generally pretty warm in the Sea of Cortez, I usually dive my anchor after setting. It always digs in. You will love the Mantus.

Cheers, Bill

[motion30]

I have a 105 lb mantus anchor and I have been anchored full time for almost 2 years. Instead of the grease I use 5200 when I assemble the anchor. I have not had a concern since and I've never seen a loose bolt

[groundtackle]

PaulinOz,
I appreciate all your comments as we are sizing anchors constantly building a substantial data base.

Great to hear you have and the vessel came stock with that windlass and related system, envious. Unfortunately many don't and cannot handle the additional anchor weight and rode, so they upgrade. Then the bow roller isn't up for it, so they upgrade. We all want strong so 4 bolts instead of 2 when mounting something, then a bigger backing plate etc. Its a vicious cycle that adds weight and then you need a bigger anchor. All vessels are weight sensitive to a certain extent and even though yours can carry, some consideration must go into how much and where the weight is placed.

In your words this is one situation I would be concerned-
"There has been situations in which I could not get the anchor to set and hold to my satisfaction (full revs reverse on two 54 HP's for 60 seconds), in these cases we moved a bit and re-set. Usually very weedy or very sloppy mud."
Most don't have that kind of power to set a big surface area. The need to bury the anchor is important, I need to feel and see it working. If it trips out I must know it will go back in. Moving a little over there and trying again till it hooks up doesn't give me the confidence it will reset. If it drags at all and gathers weed its trouble.

Mantus is a good anchor and the feedback here proves that. Any newer design in the right bottom will spill your drink when you set will speed, love that feeling. I guess I'm always interested in exploring new technology.

Whatever anchor you choose it needs to go underground fast then continue to dive till it can't go further in different substrates/conditions. If yours does that then you have the correct one.
Cheers, Chris

[a64pilot]

I think it’s funny thinking that a 40 Kg Rocna May be too big for an L450.
I have a 40 Kg Rocna on my little 38’ mono.

RE Loctite, Loctite seals the threads and as well as providing resistance to loosening, it also likely will help prevent corrosion between the bolt and nut threads. I see no downside to using blue Loctite myself. Maybe not necessary, but can’t hurt.

[groundtackle]

my 3 cents-
Loctite has its place, the application and type must be followed, they provide excellent information.
In this wet environment my experience is not loosening but getting things unloose.
Moisture ingress can also cause crevice and a host of other corrosion's in that environment. The nut/bolt interface can creep through loading or thermal expansion/contraction. You wouldn't know there is an issue unless you take the item apart for inspection.
One day when checking torque, the nut moves, breaks the loctite (or sika seal) then it must come apart, clean all the threads and do it all over again. What a pita.
Again my preference is Lanicote, Tefgel or Res Q Steel (If you can find it). That goes the same for keel bolts/nuts and anything else in that poor environment.
No spring washers, they rot out.
Minimally only premium marked 316L fasteners.
A good friend and author just emailed me regarding this issue. His testing Mantus came with mild steel bolts. He also correctly points out Skipmac's post #15 saying his came with galvanized and all look the same material. A spring washer has a different purpose so alloy and heat treatment is different than the nuts/ bolts.
He also discussed and we have in the past replacing his Fortress bolts with aluminum. The Aluminum Excel he uses as a main bower comes apart but the ingenious interlock eliminates any load bearing on the captive bolts. He is using 2000 series al fasteners until he gets some 7075. But that's another subject.
I really believe the rumor about Mantus holding on one bolt should get squashed. You load that fluke/shank flange on one bolt and give it a good tug... something will break or bend or both.
Greg..chime in. something to add I'm sure.
Cheers, Chris

[evm1024]

I doubt that anyone tinks that you should deploy a Mantus anchor with only 1 bolt....

The "comment" that one bolt has enough strength to carry the entire load is simply a way of showing that the strength of the bolts is not a "real" factor.

As an example an 85# Mantus comes with 5/8" Grade 5 galvanized bolts. Each bolt has a tensile strength of 37,200#. And 3/8" G43 galvanized chain has a breaking strength of 16,200#. Thus in a straight line pull that single bolt is about 2 times stronger that 3/8" G43 chain.

Of course the bolt will not be loaded in a straight line, and no one is suggesting that. It simply is used to point out the scale of the strength of the bolts.

Oh, most anchor tests are straight line pulls. Go figure.

Galvanized Mantus anchors ship with Grade 5 bolts. If anyone got something other than Grade 5 bolts then they should contact Mantus. I'm sure they would send out a new set in short order. Customer service is one of the many things that Mantus does very well.

[evm1024]

I'm using an 85# Mantus on my 32,000# boat. When I go to full time cruising I'll upgrade to a 105# Mantus. I'll also have a spare set of bolts but I do not expect to ever need them.

As I noted a few posts back you do not need much torque on the lubricated Mantus bolts. It took me a bit of research to understand what was going on.

The gist of it that what is actually important in any bolted joint is the "clamping force". That is the force that holds the 2 parts together (like the shank to the fluke).

It is hard to measure clamping force but easy to measure torque. And thus torque is used to get the required clamping force. When a bolt is lubricated (with lanolin in Mantus bolts) the friction that has to be overcome in turning the bolt decreases and thus a lower torque is needed for the same clamping force.

The expected clamping force for a 5/8" bolt might be in excess of 12,000#. And with 4 bolts holding a Mantus shank to the fluke we might have over 48,000# of clamping force.

What this means is that in order to cause the shank to part from the fluke we need a 48,000# pull. I'm sure that my chain will part long before, or the hard points will rip out of the deck. Of course this ignores lots of details but you get the picture.

The real worry for most of us is the worry that a bolt will come loose. We see that in comments about checking the bolts etc. However, I would note that there are hundred(s) of bolts in my Perkins engine. They are subjected to oils, vibrations, heating cycles and they do not come apart. They use split washers to lock them in place and are torqued to present the proper clamping force.

A more likely cause of a bolt coming loose in Mantus anchors is the effects of sea water on metals in general. Mantus anchors are supplied with lanolin and the instructions state that it should be generously applied.

I expect that this does at least 2 things. It acts as a seal that prevents seawater from getting in between the shank and fluke and between nuts and bolts. It lubricates the galvanized bolts which prevents melting and galling of the zinc galvanizing when a bolt is tightened. And who know what else.


One last thought - each anchor design has its strengths and weaknesses. Each has failure modes and we as prudent sailors check for those.

There are some big advantages to a bolted on shank. The first is reduced shipping costs, the anchor can be shipped broken down (it takes up less volume). Replacement parts can be shipped. Heck, even just the ability to replace a failed part is an advantage vs replacing the whole anchor.

You can keep a spare anchor stored down below in parts taking up less space. Moving the disassembled parts of a 105# Mantus around is a bit less of a chore than a whole 105# anchor....

N.B. I have a day job that pays the bills. I do sell Mantus anchors on the side. Biased? Perhaps. But than again I have owned and used a bunch of modern anchors and older generations too. If you are in the PDX area and want to see if a Mantus anchor fits your bow roller let me know. I'll loan out out to you for a week or so.

[Moontide]

Had same concern before buying my 65 lb Mantua 4 years,ago. Would buy it again in a heartbeat. Bolts have never been a problem in 4 years of cruising California, Mexico, down to canal, up to Chesapeake and now second season in the Carribean.

Friend with a 450 bought a 85 lb one and loves it. I have a 470 which, despite the name, is a smaller boat wind and weight wise. The 85 fit fine on his 450.

I think all the spades are probably pretty equal in performance Have no doubt they are all superior to deltas and other prior generation anchors.

I would suggest you consider using whichever spade as primary.

Bill

[Scout 30]

For anyone interested Defender has 80lb Manson Boss anchors on clearance.

https://www.defender.com/product.jsp?path=-1&id=3279193