On Fri, 06 Sep 2013 08:37:14 +0700, Bruce in bangkok
wrote:

On Thu, 5 Sep 2013 15:18:14 -0400, " Sir Gregory Hall, Esq·"
åke wrote:

"Bruce in bangkok" wrote in message
. ..
On Wed, 4 Sep 2013 11:38:47 -0400, " Sir Gregory Hall, Esq·"
åke wrote:

"Bruce in bangkok" wrote in message
m...
rOn Tue, 3 Sep 2013 16:32:57 -0400, " Sir Gregory Hall, Esq·"
åke wrote:

"Wayne.B" wrote in message
news:m9ca29dsbg75nlfbc151s173die229i1u3@4ax. com...
On Tue, 03 Sep 2013 07:26:09 +0700, Bruce in bangkok
wrote:

But Gregory, a 30 lb. danforth will hold a boat perfectly well. It
depends on the anchorage and the weather and water.

===

We have used a 30 lb Danforth as a day anchor in some pretty severe
conditions. With enough scope and a good bottom it holds our 70,000
pound trawler just fine (30 kt winds, exposed anchorage with 3 to 5 ft
seas).



LOL! There's a man confident in his luck!

Myself, I'd rather rely on using an anchor that is appropriate for the
heft and windage of the vessel. For a 70,000 pound trawler, a 45-pounder
would be the absolute minimum. Even so, I'd be sure to use two of them
Bahamian-style so I could feel secure through most any normal weather.
(Not talking tropical storms here!)


Interesting. Wrong, but interesting.

The Mont, later renamed several times and last named the Seawise
Giant, claimed to be the largest ship to ever sail the seas, had a
gross weight of 825,614 tons and used a 86 ton anchor. i.e. the ship
was 22,937.7 times the weight of the anchor.

The Trawler you describe is 1,555.5 times the weight of the anchor
that you mention.

Or perhaps a better way to describe it is the trawler gross weight to
anchor ratio is far higher then that of what is said to have been the
largest ship in the world.

Using your criteria of gross weight to anchor weight the trawler
should be using an anchor of 3.05 pounds.

Or, to put it another way... you have proven, yet again, that you
don't know what you are talking about.

Did I not also mention windage? Weight is of less consequence
in smaller private yachts than is windage. So your diatribe has
little actual meaning when it comes to smaller recreational craft
as it's not the weight that breaks them loose but the force of
the wind acting upon their surface area exposed to the wind.

Ah, windage... I can only assume that you somehow believe that a
70,000 pound trawler has more windage then a 1,651,228,000 pound
tanker.

As was previously mentioned, you have proven, yet again, that you
don't know what you are talking about.


Get a clue, dock boy! If you had a BILLION pound ship but
no wind or current you could anchor it with a ten-pound rock
and it would stay put.

And you prove your brilliance yet again. "If you had a BILLION pound
ship but no wind or current". Would you care to elaborate on these
conditions and where one might encounter them..... other in your
fevered dreams.


Bruce, how come you often argue like a girl? Like a girl,
you don't seem capable of embracing an absolute that
demonstrates a point and demonstrates it well.

A billion pound ship that can be anchored by a ten-pound
rock is an absolute that proves it's not the tonnage that
drags anchors but the force of the wind and current acting
upon that tonnage, which is represented by surface area
upon which the wind can act, that causes anchors to drag.

This all goes to prove that your assertion that one requires
X pounds of anchor to properly anchor XY pounds of vessel
is deeply flawed.


You can't read?

Above someone wrote:

"Myself, I'd rather rely on using an anchor that is appropriate for
the heft and windage of the vessel. For a 70,000 pound trawler, a
45-pounder would be the absolute minimum. Even so, I'd be sure to use
two of them Bahamian-style so I could feel secure through most any
normal weather."

How soon they forget.... even what they themselves said.

It's a flawed formula because as I have proven, using an
absolute, that it's the windage that matters as much or more,
in real life conditions than the weight and your dumb formula
complete ignores the wind and windage. In other words, you
tried to sound like an expert but you failed.

But it is a formula that you dictated. After all you stated, in the
above, a very specific ratio of a 45-pounder anchor for a 70,000 pound
trawler.

Are you now saying that is incorrect? Or that you told a lie?


====

Frankly I don't think there'a any prevarication involved, just
differences of opinion, perhaps stretched a bit in the interest of a
"lively" discussion. And there's no end to the lively discussions
about anchors and anchoring. It's a favorite topic where ever
cruisers congregate. There are some good formulas for wind loading
that take vessel size and shape into account. Some have atttempted
to throw in a fudge factor for sea state and accompanying surge loads
but those are guesstimates in my opinion. Almost all reputable
anchor manufacturers publish a table of recommended anchor size based
on boat length but those are also little better than guesstimates
since they don't comprehend weight, windage or sea state, and only
rarely is an assumed wind speed stated. My personal preference for an
all around working anchor is to get the heaviest one that your
windlass can handle and that your boat can carry comfortably. I
select type based on testing and for the widest possible range of
bottom conditions since you don't always get to pick an ideal spot.

We were carrying a 125 pound Spade anchor for a while because it got
great test results by just about everyone, and because we had a 45
pound Spade on our previous boat that was arguably the best all around
anchor I'd ever used. The 125#, although a very good anchor, was
right at the upper limit of what we could deal with, and eventually it
started to show some signs of structural rust after 8 years of serious
cruising and a *lot* of time at anchor. We replaced it last year with
the 88 pound Rocna that we are using now. It doesn't set quite as
fast as the big Spade bit it's plenty fast enough under most
conditions. We usually back down hard with both engines to test the
set and it has never dragged after passing that hurdle. It's the
kind of anchor where you can get a good night's sleep no matter what.
My goal when sizing the anchor and related components is to survive a
50 knot thunder squall without dragging and we have done exactly that
on several different occassions.