Displacement to Anchor Weight Ratio

[JonJo]

Noelex,

There are thousands of Americans who use a Fortress as a bower anchor (including the US Navy and Coastguard) and there are thousands of Americans who use their Fortress on a regular basis. I am sure many of these are small anchors on runabouts and some only use their anchor for lunch stops. However their are enough users of the Fortress on CF alone to be representative.

Has it occurred to you that you are the only person to report Fortress as having this problem on re-setting. The thousands who own a Fortress seem quite comfortable. The cruisers who carry a Fortress, commonly as their storm anchor - their anchor of last resort, never post of the dire consequences of what happen, when the tide changes? If there were a serious problem in using a Fortress in tidal areas the issue you describe would be well documented and Fortress would be some minor supplier (if it survived at all).

The reality is different - Fortress are a major and enduring player in the International anchor market, cruisers carry Fortress (often as their anchor of last resort), cruisers carry a Fortress and some use it as their main anchor and thousands use the anchor quite happily and there are not reports of Fortress anchors dragging during a change of tide or wind (and from what I recall the tide changes quite frequently).

I note you are quite happy to denigrate certain anchors (some of which you have never seen and most you have not used). I also noted that when a certain video was touted as fact and when a certain shank was described as weak (and admitted so by the manufacturer) your vast knowledge was oddly silent. In fact you were questionably absent in your denigrating comment then. I recall a certain image of a reputable anchor with a bent toe, that then enjoyed a minor and much later apology when it was admitted that the image was the only bent toe ever to have been reported in almost 10 years. I do wonder at your agenda.

I like a little balance

Jonathan

[hpeer]

320 on the Pape
400 on the Brewer

Ours are epoxy paint coated, cause I had some extra left over.

[sailorboy1]

how did this thread turn into a concave/convex/flat issue?


wait I know, someone couldn't let a chance go by

[noelex 77]

Originally Posted by JonJo

Has it occurred to you that you are the only person to report Fortress as having this problem on re-setting.

Jonathan, you have been involved in enough anchor threads to have heard the same sentiments expressed by others. That of course does not necessarily make the statement correct, but I am puzzled why you are asserting that I am the only one with this view, when you know that is not the case.

[ranger58sb]

Originally Posted by JonJo

Has it occurred to you that you are the only person to report Fortress as having this problem on re-setting. The thousands who own a Fortress seem quite comfortable. The cruisers who carry a Fortress, commonly as their storm anchor - their anchor of last resort, never post of the dire consequences of what happen, when the tide changes? If there were a serious problem in using a Fortress in tidal areas the issue you describe would be well documented and Fortress would be some minor supplier (if it survived at all).

Ummm... Our well-set Fortress failed to reset once.

A fast storm came through, quickly rotated the boat 360° around the anchor.... and off we went.

Given the circumstances -- circular motion, storm intensity, etc. -- I didn't worry too much about it. In fact, it hadn't actually started with the rain yet, and we were only a mile or so from our home dock (intending to enjoy a quiet dinner aboard at anchor)... and it was easier/prudent to simply bag it for the evening.

We brought the anchor in as quickly as we could (mud and all), beat feet for the home slip, got there in the alternating pitch dark/lightning, had time to give the First Mutt a quick walk and got him back onboard.... followed by immediate deluge. For several hours.

Anyway, back to the anchor... I can't say it wouldn't have reset once the circular motion stopped... but I can say those peculiar circumstances broke the anchor loose.

I don't know that any other anchor would have done better.

-Chris

[TacomaSailor]

Sheesh!

If you have not had a anchor drag under some unusual circumstance then you have not been cruising enough!

All anchors will drag when used in the wrong combination of bottom, surge, wind speed, scope, wind direction

There is no 100% correct anchor for every situation - that is why I carry three different types

[motion30]

I have had my Danforth fail to reset on tide changes several. times l. One time.i woke up to discover myself on a mud bank. Another time I awoke in the middle of the.night to find myself dragging down on other cruisers. Soon after the . Danforth was.replaced.by a mason supreme, Now I sleep better

[ranger58sb]

Originally Posted by TacomaSailor

Sheesh!

If you have not had a anchor drag under some unusual circumstance then you have not been cruising enough!

All anchors will drag when used in the wrong combination of bottom, surge, wind speed, scope, wind direction

There is no 100% correct anchor for every situation - that is why I carry three different types

Yep

Twaren't the anchor's fault

-Chris

[DumnMad]

Originally Posted by sailorboy1

how did this thread turn into a concave/convex/flat issue?


wait I know, someone couldn't let a chance go by

The anchor thread hijacker strikes again

[TacomaSailor]

The wide variety and style of anchors is a plot by the beer makers of the world. They keep the controversy stirred to a simmer so that we sailors will have a topic of endless duration to discuss over countless beers.

And... as we all know - the more beer we drink - the more we know about our particular anchor and the more desperate where the circumstances and consequence of our last or most interesting dragging episode.

That is why - I keep a 6-pack of of Anchor Steam on board in case someone questions by choice, technique, location, or otherwise wants some sage advice about staying put!

[sailorboy1]

Originally Posted by TacomaSailor

That is why - I keep a 6-pack of of Anchor Steam on board in case someone questions by choice, technique, location, or otherwise wants some sage advice about staying put!

A 6-pack ................................. light weight!

[TacomaSailor]

Originally Posted by sailorboy1

A 6-pack ................................. light weight!

See - there you go again - a displacement discussion... and it has been 15 years since anyone called me a lightweight!

[DoubleWhisky]

My boat has 1: 650 ratio for Rocna. It is correct weight according to manufacturers sizing chart and is O.K. for my Med cruising
My general opinion is that for SHHP anchors of new generation the ratio of 1:500 is good for everything, including violent storm. Of course, if weight resulting from such a ratio is between chosen anchor model sizes, the bigger one is the proper for the boat.
For real high latitude adventure one size bigger would be advisable probably, and for average cruising (like Med, Caribbean out of hurricane season) one size smaller would be completely adequate. It's only my opinion of course and only in regard of new gen steel anchors.
By the way - windage is prevalent (over displacement) factor in extremal situations only in static model. Inertia of heavy boat riding the waves in not taken to account in such a model, and this generates peak loads on anchor and rode.

Regards

Tomasz

[DoubleWhisky]

Originally Posted by Sharki127

Amel 55 48,000lbs 66lb Bugel 727 to 1
Amel 64 75,000lbs 92.4lb Bugel 812 to 1
Morris 45 22,300lbs 45lb CQR 496 to 1
Morris 48 32,000lbs 45lb CQR 711 to 1
Morris 52 40,300lbs 55lb Delta 733 to 1
Oyster 475 35,273lbs 44lb CQR 802 to 1
Oyster 545 46,893lbs 75lb CQR 625 to 1
Oyster 635 73, 854lbs 75lb CQR 985 to 1
Halberg Rassy 48 40,700lbs 70lb Delta 581 to 1
Halberg Rassy 55 58,000lbs 70lb Delta 829 to 1

I'm still to see the boat coming out of the yard with proper anchor arrangements.
I do believe that popularity of older design anchors with boat manufacturers is a result of two factors:

• older ones are cheaper
• the sizing charts for old designs are lenght based only and suggesting heavily undersized anchors - cheaper further.

Amel is probably somewhat of an exception, as it is rigged for and supposed to use double anchoring in anything over average conditions.

Regards

Tomasz

[congo]

doubleWhisky Wrote:

By the way - windage is prevalent (over displacement) factor in extremal situations only in static model. Inertia of heavy boat riding the waves in not taken to account in such a model, and this generates peak loads on anchor and rode.

Regards


Tomasz



Rex Wrote:

As our anchor types are certified as S/H/H/Power anchors, boats under survey have their anchor sizes specked by survey officers, they take in rigging, length, weight, displacement the list goes on, quite often a customer building a large yacht will ask my advice on all of the above mentioned, I will simply give them a size I would recommend, if they want more accurate specking and piece of mind I give them a surveyors name and they will then have the surveyor spec their anchor.

As a large part of our business is suppling boats under survey we have found with the many years of working with survey officers our anchor sizing recommendations to be very reliable as they are close as what we are used to seeing the survey officers spec for boats under survey.

From my experience if someone really wants the homework done correctly for their boat taking in all mentioned points and more above, employs a survey officer, they are not cheap but rarely get it wrong.

Sometimes boats are purchased with dual heavy duty bow roller fittings, in some cases the boats history has been used in survey, depending on the deployment they may be required to carry two anchors, under survey the extra anchor must be fixed in the same way as the primary so if one anchor fails, or winch failure the second can be deployed instantly, it is certainly not primary use of two anchors deployed at once, though it is done.


Rex Wrote: