Mantus Anchor on Test

[noelex 77]

Originally Posted by autumnbreeze27

I'd like to know if people weld the bolts, or put something on them to keep them from rusting?

The bolts are galvanised.

[sailorboy1]

Anchor tests and discussions are just such old "news". Since there are still $1m boats coming new with CQR anchors I am starting to believe than in the end they haven't really gotten much more advanced than a rock with a hole in the middle for attaching with a rope.

[motion30]

Originally Posted by autumnbreeze27

I'd like to know if people weld the bolts, or put something on them to keep them from rusting?

I'd like to see how one fails, and how that compares to a similar but welded together anchor. Maybe hook two together and use a tractor to pull them apart until one breaks.

Mantus supplies grease, I used 5200 on the bolts and also on the mating surfaces

[hpeer]

Originally Posted by autumnbreeze27

I'd like to know if people weld the bolts, or put something on them to keep them from rusting?

I'd like to see how one fails, and how that compares to a similar but welded together anchor. Maybe hook two together and use a tractor to pull them apart until one breaks.

Galvanized. I got two sets of bolts with my anchor. Mistake?

But I also paint my anchors with zinc epoxy paint. Having two steel boats I have it around and it's someplace to use up your last few brush dulls without pitching it. Can't see any harm to it.

[noelex 77]

Originally Posted by hpeer

Can't see any harm to it.

It is common practice. And I think helps extend the life of the galvanising. It can also be used to make the anchor more visible underwater.
Finally it makes the anchor a bit less likely to be stolen.

However, there have been cases where galvanisers refuse (or charge more) to re-galvanise painted anchors.

One of the advantages of the Mantus anchor is that transport and regalvanisising will be easier especially for larger models. Anchoring full time in hard sand I find galvanising only lasts 3-4 years so it can be an important issue.

[DoubleWhisky]

Originally Posted by sailorboy1

Anchor tests and discussions are just such old "news". Since there are still $1m boats coming new with CQR anchors I am starting to believe than in the end they haven't really gotten much more advanced than a rock with a hole in the middle for attaching with a rope.

For me it is just sad thing, how the many builders go for such a small savings on >$1m boats...
And it make me thinking about savings on cheaper boats...

[JonJo]

Mine came with, grease, spring washers and the bolts were galvanised. If as, partially, intended you frequently dissasemble I'm not sure how long the gal will last - maybe that's why people get two sets of bolts? My bolts were mild steel - hence my interest in whether Noelex checked - given they are a rather critical component.

I'd be recommending that anyone buying throw the bolts away (if they look as grotty as mine did) and replace with US made gal construction bolts. Cheap, imported, (gal) construction bolts are notorious.

Jonathan

[noelex 77]

I usually find that galvanised shackles have about the half the lifespan of the galvanising on the anchors, but these are subject to wear from movement between the shackle and chain or anchor attachment point. This movement wears off the galvanising.

The anchor bolts are not subject to any movement so should have a similar life to the rest of the galvanised finish. If it is a bit shorter they are easily replaceable.

[JonJo]

Noelex,

I was thinking more in terms of someone who wants to frequently disassemble (which is supposed to be one advantage of the Mantus) where the gal would be worn off the threads. This has 2 issues, one the gal wears off with potential for corrosion and bolts to be galvanised are made over size (or the nuts are) and with loss of gal you lose some security. No one would use an anchor shackle without securing the pin, mousing, Loctite, peening - where is the security on the Mantus bolts - a spring washer?

I think if the anchor is left assembled the gal, in the critical areas, will last as long if not longer than the gal on the anchor. Though any bolt corrosion will not be seen.

Most anchors last for ever, most people would expect their anchor to last forever, most people (once they have an anchor) never think seriously about it again - I'm not sure that checking bolts will occur to most people - after all, anchors last for ever. You results will be viewed critically here but those 'most' people, some, will treat them as gospel - and not checking the bolts before using them does not engender much comfort.

But I still would be wary of imported HT gal bolts. Buying European or American gal HT bolts is not a big cost.

Jonathan

[noelex 77]

Originally Posted by JonJo

Most anchors last for ever, most people would expect their anchor to last forever, most people (once they have an anchor) never think seriously about it again - I'm not sure that checking bolts will occur to most people - after all, anchors last for ever.

I wish this was true
Anchoring full time in hard sand galvanised anchors only last about 4 years before they need regalvanising.

The anchor shackle (which is single bolt verses 4 which hold the anchor shank) is in area that is subject to movement and wear of the galvanising is going to need far more inspection than the 4 bolts that hold the shank to the fluke.

Especially as there is considerable redundancy in the bolts. Mantus claim that:
"Although the shank is attached to the fluke with 4 bolts, a single bolt has sufficient strength to handle the maximum expected load on the anchor."

[JonJo]

Originally Posted by noelex 77

I wish this was true
Anchoring full time in hard sand galvanised anchors only last about 4 years before they need regalvanising.

You are lucky (or unlucky in terms of anchor longevity), most people only anchor a few times a year and its the 'most people' who form the bulk of the market for anchors (and any yacht equipment).


I'm surprised Andrew has not made a comment - he has pretty strong views on HT chain, it seems difficult to believe he would not be equally critical of gal HT bolts.

Jonathan

[noelex 77]

Originally Posted by JonJo

Before you grind the bolts smooth (in use) I wonder what specification of bolts you have with your model - they will be clearly marked on the bolt heads.

I finally got a photo of the bolts as requested by Jonathan. Sorry for the wait. The heads of the bolts are only visible under the anchor (the tightness can be checked from the top looking at the amount of thread visable above the nut)

In the end a friend made it easy by photographing the underneath of the anchor from his dingy while the anchor was on the bow roller. Thanks Andy.

The Mantus is now back on the seabed, where all anchors belong

Here is the photo:

[noelex 77]

Andy also took this underwater photo of my anchor coming up.

[noelex 77]

Plus this artistic one:

[JonJo]

Hi Noelex,

Your bolts appear to be Metric (odd coming from America) HT bolts Class 8.8, 800 MPa. Normally they would be marked also 8.8, but marking standards vary. Imperial Class 5 bolts have similar marking pattern (you would think it would not be difficult to have international marks without confusion) but the radial marks on the Imperial Class 5 are almost the complete radius in length, rather then the short radial ticks on the metric Class 8.

I hope yours are American sourced galvanised metric Class 8.8.

Thanks for the image

Jonathan