Mantus Anchor on Test

[evm1024]

I played with the bolt image a bit and think that they are Grade 5 Slip Critical bolts.

3 lines and an S-C

Take a look

[xeon_tsd]

I have a 65lb Mantus (29.4 Kg). I will look at my bolts this weekend when I make it down to the boat.

[sailorboy1]

gee, wouldn't be easier to just ask Mantus to post the bolt info on the thread if it is going to be such a hot issue?

[motion30]

This in my 105lb mantis

[JonJo]

I asked because mine, from 12 months ago, were mild steel and marked as such, below the minimum specification declared by Mantus at the time - so asking Mantus is not the answer. When queried Mantus assured me they were still adequate and the attachments were well over-engineered and that one bolt alone had sufficient strength (they were not suggesting 1 bolt was enough just that one bolt had more strength than would be imposed on all 4 bolts).

Interestingly there are a number of demountable anchors - not one relies on the bolts to take the load. All are designed that the load is taken some other way and the bolts are non-loadbearing, Fortress, Spade, Kobra, alloy Excel.

It is a hot issue - its what holds the anchor together - but maybe that's a minor issue Bolts, primarily HT gal boats imported, are known to fail, building in Melbourne; bridge, currently being built, in San Francisco - I think there is quite a long list.

Jonathan

[noelex 77]

It is hard to get a perspective from the photos and the Internet in general, but these are "bloody big bolts".

I am no engineer, but a rough calculation suggests that even a single bolt on my Mantus anchor (18mm G5) is over twice as strong as my chain (10mm G7) Given my rusty applied maths this may be wrong. (Could a proper engineer check?), but it is very hard to imagine, just from the appearance, that even a single bolt would not be adequately strong.

The anchor bolts would be mostly in shear which provides greater reserves than the chain which is under tension.

[motion30]

Originally Posted by noelex 77

It is hard to get a perspective from the photos and the Internet in general, but these are "bloody big bolts".

I am no engineer, but a rough calculation suggests that even a single bolt on my Mantus anchor (18mm G5) is over twice as strong as my chain (10mm G7) Given my rusty applied maths this may be wrong. (Could a proper engineer check?), but it is very hard to imagine, just from the appearance, that even a single bolt would not be adequately strong.

The anchor bolts would be mostly in shear rather than tension (like the chain) which provides even greater reserves.

The 105 lb has 4 5/8" perhaps 4 galvanized structural bolts would be a good investment

[model 10]

I don't get you guy's. You buy an anchor that you need to hop up with better bolts. Bolts? What the hell are you doing with bolts in your ground tackle?

[Cotemar]

Originally Posted by Guy

I don't get you guy's. You buy an anchor that you need to hop up with better bolts. Bolts? What the hell are you doing with bolts in your ground tackle?

No hop up required. noelex 77 is using a production anchor with the supplied bolts. These anchors are demountable for possible storage.

[motion30]

there's lots of bolts in a high rise condo. never seems to be a problem

[model 10]

Originally Posted by motion30

there's lots of bolts in a high rise condo. never seems to be a problem

If there were high rise condo's at anchor there would be.

[motion30]

Originally Posted by Guy

If there were high rise condo's at anchor there would be.

That did make me laugh. .

thanks

[JonJo]

Bolts in this application, anchors, take all the load and the load is applied as a snatch load on a regular basis. I'm not sure that construction bolts are tested for repeated cyclic snatch loads - but as has been pointed out, I'm no engineer. I am sure this method of assembly is all fine (but I would not use one until convinced by someone, independent, who knows what they are talking about).

Jonathan

[Cotemar]

I think noelex 77 is the independent review your looking for. He has a beautiful boat that he wants to keep that way. His review and time spent will be very valuable to us here on the CF.

[Factor]

I too have a beautiful boat that I want to keep that way. As does Jon Jo, as does almost everyone. I have owned Rocna, Manson Supreme, Delta, Manson CQR, Genuine CQR and SARCA Excel and Fortress. All purchased with my own money, none given to me for free to "test". The reality is 95% of the time they all work okay, in that last 5% my choice is Sarca Excel and Fortress as secondary/spare/backup. When I save a few more dollars I might get an alloy excel, its a cat a weight saving on the front end is a good thing.

Noelex is providing one data point, there are others.