Anchoring with 4:1 Scope?

[SV__Grace]

Originally Posted by Mike OReilly

Comes down to maximizing the factors that are within our control as a way to minimizing or mitigate all the things that are out of our control. All this talk has me wanting a bigger anchor. The Excel is looking better and better, but damn hard to find one in my neck of the woods (even if I had the extra grand to spend). Someday...

Mike, checking out your blog, you seem to be in Canada. I got my Excel from https://www.groundtackle.com who imports them from Anchor Right in Australia and had it on my boat within a week of ordering it. Those guys are great to deal with, and are in Canada.

They are competitively priced compared to other new gen anchors. I paid @$150.00 more than I paid for slightly smaller the Rocna Vulcan it replaced (33kg Rocna, 36kg Excel), but I sold the Rocna for $800.00 to a fellow cruiser so my net cost was only @$450.00!

[MathiasW]

Originally Posted by Dockhead

If you can't find an Excel, why not a Spade? Or a Mantus? I know Spade is expensive, but to my mind very well worth it, as I think pretty much anyone who has tried one will tell you. If you are trying to handle a much bigger anchor, Spade has a big advantage in that it is ballasted with lead, so much better balanced than most other anchors. This really helps not only with setting, but also with handling, as it comes up right way up (no swivel needed), goes down in a stable position. Downside is galvanizing.

I have a 35kg Spade and I am very happy with it. Here in Panama it has been mostly very soft mud for us to anchor in. At higher wind speeds, it is unavoidable to see a slight drag, say beyond 28 kn, but it seems very good at resetting and coping with strongly veering winds. I had opted for the more expensive X160 version, as my chain is duplex and I wanted it all to be of as much as possible similar material to reduce galvanic corrosion. Still, next time I would go for a 40 kg variant of it...

But mind you, with the holding power of an anchor only increasing roughly linearly with weight as Thinwater had pointed out, but the wind force rising quadratically with wind speed, it is an uphill battle that you cannot win. So upgrading to a 40 kg anchor would gain me only a factor 1.07. So, instead of 28 kn, it would start dragging at 30 kn...

[Mike OReilly]

Thanks DH, and Grace.

Yes, Spade would be a good choice, but they really do seem excessively priced compared to others. For the comparable size it looks like Spade would be nearly double the price. I don't mind spending money on good equipment, but they don't seem to be twice as good as the others...

I like Mantus. My dream setup is to have something like a Mantus as a backup, with a primary Excel, Spade or maybe a Vulcan.

GroundTackle looks great Grace. Thanks! I wonder what the shipping charges are to Newfoundland. Guess I'll ask once I get back to my boat, which will hopefully be this year. But might not be till 2022 if the vaccines don't roll out fast enough.

To be clear, I've had a 55# Rocna for years now. It has never let me down once properly set (and dug in ). And I do anchor in some challenging places at times.

The Rocna is slightly oversized for my boat, but I know I can manage something a little bigger. I've also become less enamored with the roll bar approach. Again, not that I've had any direct negative experiences, but I listen to the new testing by Panope and others. The new-new gen anchors without roll bars seem to be winning the test face-offs.

[rslifkin]

The price of the Spade is part of what drove me to the Vulcan initially. Fitting a roll bar is a no-go with my pulpit, other than a large Mantus which wouldn't have self launched or retrieved due to pulpit length (roll bar would fit over the end, but manual lifting would be involved).



The Spade is quite pricey, so that pushed it down the list. Tip to hull clearance is a concern on my setup and the Vulcan has more of it than the Excel, so I went with the Vulcan (in 73lb form). With a little more modification to the roller and a plate to protect the hull I could have squeezed the 88lb model on there, but I didn't see the need, as the 73lb was already a decent bit bigger than the recommended 55lb.

[Dockhead]

Originally Posted by Mike OReilly

. . .Yes, Spade would be a good choice, but they really do seem excessively priced compared to others. For the comparable size it looks like Spade would be nearly double the price. I don't mind spending money on good equipment, but they don't seem to be twice as good as the others.... . .

The cost of the Spade has a rational basis. Note that I'm not selling them, and they have some disadvantages. But the construction of the Spade is elaborate and with consequences. For one thing, the shank, instead of being a simple piece of cut steel sheet, is a fabricated triangular hollow section, making it far stronger and far lighter than other anchor shanks, very desirable qualities. Lighter means the anchor has better balance. Stronger is very desirable because of shanks get bent. I bent the shank of my Rocna.


The lead ballast and cast steel tip is the other expensive detail, as opposed to simple folded/stamped steel sheet.


On the down side, however -- the galvanizing is poor and it is very difficult and expensive to regalvanize them. Frequent use keeps the rust off, but Spade anchors look shabby in the winter or whenever you're not using them frequently.


The other downside is that althought the tip is very sharp, it is voluminous since it's filled with lead. There are some bottoms where a thinner tip of the fluke slices into the bottom better (Mantus).


But altogether worth the money, if budget somehow allows.

[Mike OReilly]

Originally Posted by Dockhead

The cost of the Spade has a rational basis.

Price is rarely "rational" in market-driven economics in the sense of input costs = price. Good on them that they can command that rate, but price is mostly set by what people are willing to pay.

I'm sure you're correct in your assessment of construction. I'm simply stating that Spade doesn't appear to perform any better than the other top-performing anchors that I would consider when I go to purchase. Whatever their construction, they don't appear to be worth the additional cost these days -- at least not when I look at all the test data and anecdotal reports.

But of course my assessment is also subjective and open to wide error bars, just like most anchoring scenarios. I just don't see the added value here, but if others do, I certainly would not quibble.

And I'd certainly would have no qualms using a Spade if the anchor fairies suddenly delivered one to me .

[MathiasW]

Originally Posted by Kamen

Hi Mathias,

I purchased your app and installed on a Samsung Galaxy S20 device. The text is truncated at the right and bottom edges, which hurts usability. I am attaching a screen capture.

Thanks
Kamen

Attachment 230396

Just for the records, I believe this issue is fixed now...

Always happy to receive feedback to improve the app.

[Just Another Sa]

Originally Posted by MathiasW

Now, in a gust, the snubber / bridle will stretch more and so the block would move further down the line, with an increase in the chain's potential energy. That is good. But the same would also be true, when the wind eases a bit, the snubber / bridle shrinks, and the block moves further up the line. Also in this case would the chain's potential energy increase. This latter case might sound good at first, but when looked at it from the opposite side, so coming from a situation where the wind is blowing less and then picking up, it means that potential energy is lost in this chain segment and needs to be compensated for elsewhere. This is not good.

So, the conclusion is one should at most have this free-hanging shape in the slack segment of the chain. Anything more is bad from an energy storage point of view.

This analysis was done on a straight line between anchor and bow roller. When catenary is still there, if only partially, this result will get modified somewhat.

Your analyses also assumes that your length of rode remains constant and thus so do actual scope. That is obviously not the case whenever the snubber stretches, causing rode to be longer and thus the scope increases if the anchor stays set in position, and the boat moves horizontally (no waves during a gust causing all that)
Here is the link for case example: hit the calculate button at the end, ant the pic below the headline Results will show the movement of the snubber connection point, which can be magnified by moving the pointer to the part of the pic under interest and clicking it.
It is then showing, that when a gust hits, the snubber connection point moves away from the bow roller, but also upwards, not downwards like a block in a fixed line. The analyses in the said link also misses one thing, any horizontal tension on the so called slack chain reduces tension on the snubber, and therefore stretch. Not relevant magnitude if the slack chain remains slack all the time, but if it's even close to becoming taut (as some here has suggested), not so anymore.