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Old 04-22-2016, 10:02 AM   #421
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Originally Posted by Xlantic View Post

One should bear in mind that the light-weight in relation to size of aluminum anchors is compounded in water. Aluminum's density is only around 2.7 times that of water. So, in water, an aluminum anchor weighs around 37% less than in air. (Steel is almost 8 times denser than water and so in water the weight loss is only around 13% less than in air.)
Interesting
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Old 04-22-2016, 11:54 AM   #422
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Under the semi-torture test aluminum or no the anchors did very well. Especially the Excel on the reducing scope test. I think the main reason it did so well is due to it's very high aspect ratio. Once that very long "foot" is burried deeply it dosn't want to (understandably) be pried out. The Fortress's and Danforths (especially the highest performance Danforth w the high aspect ratio flukes) also tend to strongly resist being levered out. The stuff of good short scope performance.

Having said that quite a few low aspect ratio anchors will hold well at short scope and I suspect the throat angle has much to di w it. If the pull on the anchor rode presents equal uplifting force on both the fwd and aft ends of the fluke the full fluke area will resist pulling out more or less equally.

However anchors basically need to rotate like an airplane taking off to come out of the seabed either being extracted by the skipper of the boat or a breakout from high wind.

I wouldn't say say it's conclusive but I do believe a smooth surface on an anchor helps an anchor set and then penetrate deeper. So a polished SS anchor probably has an advantage but nowhere near the extra cost.

I agree w you Steve that basically a fully set aluminum anchor is about the same performance as a steel one ..... but not. Firstly that presumes that they are both set and the aluminum is clearly less likely to set. And more likely to break out. People use aluminum anchors when a lightweight anchor is a big advantage ..... like on a seaplane or lightweight high performance boat. The question that comes out of this for me is the weight instead size question. Of course one can use a lightweight anchor but using an Excel, Rocna, Supreme or Spade half the size of what would be otherwise used is probably still way above the average anchor performance level .... and half the weight. I've done two 50 knot gales w anchors less that 20 lbs but may well have dragged w a 40lb average low performance anchor. Very few will start using a smaller anchor .... bigger is better is so well entrenched.

I've often thought I probably would like very much a steel Danforth from Fortress. Without much thought I can easily think of several reasons why they don't.

Lastly I think Steve has shown us that setting slowly is a great advantage and many skippers over the years that I've talked to say the best way to set an anchor is to "soak" in in the seabed. Put the anchor down in a light breeze set it lightly and go have some ice cream and then pull some more on the rode. Quite the opposite of what Steve has done much or some of the time but it has shown us the great stuff anchors can do under very demanding situations. I've talked for many years about how usable short scope anchoring can be and it was great to see just how far the envelope can be pushed. 3-1 scope for me was/is average and normal and TF members often said in response to a post of mine that "they would never anchor at 3-1". Don't think I'll be hearing much of that now. But if it's going to blow I'll be anchoring at 4 to 5 to one.
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Old 04-22-2016, 02:56 PM   #423
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Sure like Steve's seabeds by Port Townsend. Prolly be a good place for me to test my anchors. Fairly sandy w a small bit of gravel and enough mud to be easy setting andhold well w a fairly deep set. Just holding well should be a good test for my less than 20lb anchors. The old Dreadnought should like it as well. And since I won't be doing reversals the current should'nt be a problem. Steve I'll give you a heads up if I/we spend the night there. Working on my rode line now.

Re Steves tests I suspect that the first 4 - 12" of chain may be inhibiting the ability of the shank end to poke down in the seabed giving the anchor fluke more angle of attack. If this is reducing anchor performance I have a 3' (eye'd at both ends) piece of cable plenty strong enough. It may help setting at short scope and holding anytime the anchor shank tries to penetrate the bottom. Before the vids by Steve and others I had no idea the shank end would poke into the bottom w the fluke only half set and the shank mostly not yet into the substrate. I had assumed it was pointing up at the bow of the boat ... and wondered how the anchor could work at short scope. The fluke profoundly pitches the whole anchor down.
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Old 04-22-2016, 08:42 PM   #424
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Hi Eric,

Re: Seabed. My primary seabed, the one I call "sandy mud" does not contain any gravel or rock. It is quite firm and heavy. I think it is just about the ideal consistency for anchoring. Easy to penetrate and produces tremendous holding power. If an anchor will not work here, I am afraid it is hopeless.

My other test site, the one I call "sand and gravel" does not contain any mud or other "binder" material. It is in a location that almost no one uses to anchor their boat.

Re: Chain inhibiting shank penetration. If the anchor is moving, the chain (and shackle) may act like saw teeth and might help dig a trench to give the shank a head-start in burying. This might be more important in seabeds with a hard "crust" like surface.

Definitely give me a heads up when you are in town. It would be a pleasure to meet up.

Steve
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Old 04-22-2016, 09:11 PM   #425
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The Spade reset tests added at the end of the video "got lost" in the discussions, they must be impressive reassurance for Spade users. A local anchor test article in March 2014 (MySailing.com.au) says they have no distributor in Oz.
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Old 04-22-2016, 11:51 PM   #426
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Thanks for mentioning the Spade, Bruce. It did get sorta drowned out.

You may have noticed the absence of yellow paint on the Spade's fluke. The anchor did have the paint when I began my testing but it was poorly adhered to the galvanized metal (no surprise). Every time I would do a test, more paint would flake off, so about a month ago, I simply scraped the rest of it away.

Upon retrieval in this latest Spade test, we saw a significant blob of seabed attached right where the paint used to be. The seabed attachment did not seem to negatively affect the performance of the anchor but it does seem to prove that the slick paint was helping keep things clean.

Steve
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Old 04-23-2016, 07:13 AM   #427
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Thanks for mentioning the Spade, Bruce. It did get sorta drowned out.

You may have noticed the absence of yellow paint on the Spade's fluke. The anchor did have the paint when I began my testing but it was poorly adhered to the galvanized metal (no surprise). Every time I would do a test, more paint would flake off, so about a month ago, I simply scraped the rest of it away.

Upon retrieval in this latest Spade test, we saw a significant blob of seabed attached right where the paint used to be. The seabed attachment did not seem to negatively affect the performance of the anchor but it does seem to prove that the slick paint was helping keep things clean.

Steve
I guess the paint issue, like the smoothness of the digging tip begs the question......

Should we try and keep anchor surfaces slick so they penterate more easily and come up clean or stay clean to reset better..........or let the be rough so they stick better to bottom material and maybe have higher holding or better short scope performance?
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Old 04-23-2016, 08:44 AM   #428
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I guess the paint issue, like the smoothness of the digging tip begs the question......

Should we try and keep anchor surfaces slick so they penterate more easily and come up clean or stay clean to reset better..........or let the be rough so they stick better to bottom material and maybe have higher holding or better short scope performance?
And... should the tips be painted chartreuse green or crimson yellow - couldn't help myself - just kidding!
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Old 04-23-2016, 08:51 AM   #429
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Hey, from what I have seen on the video and Steve conclusions, make a lot more sense that what some have kicked around for years that in my mind has been wild guesses that are often , can't say wrong, but out there.
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Old 04-23-2016, 09:21 AM   #430
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Hey, from what I have seen on the video and Steve conclusions, make a lot more sense that what some have kicked around for years that in my mind has been wild guesses that are often , can't say wrong, but out there.
Agreed!
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Old 04-23-2016, 10:56 AM   #431
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I think it's obvious a smooth surface on anchor parts exposed to the seabed is a plus. Imagine an anchor fluke w little 1/4" knobs or buttons like bolt heads (round or hex) all over the fluke and shank.

However some smooth surfaces cause more drag than slightly rougher surfaces. Flat calm water is avoided by float plane pilots as it's "sticky" and can even prevent a plane from taking off especially when overloaded.
In the 70's a friend took his girlfriend from the Queen Charolette Is to Vancouver BC shopping. Bumped into him at Bella Bella trying to take off w all her stuff, full fuel and themselves on the little Cessna 150 on floats. He asked me to run in circles w my boat for a bit to rough up the water surface. I did and they subsequently took of normally.

That said I suspect that bumpy or rough surfaces on anchors would make them less prone to penetrate the seafloor. Any doubter has the opportunity to spearhead the next anchor breakthrough in performance by building an anchor w textured surfaces. Have at it but the very smooth surface of polished SS haven't brought about reports of polished anchors not being able to penetrate as well as the typicaly galvanized anchor like floatplanes having trouble taking off on smooth water. I 've heard many times that polished anchors come up much cleaner than galvanized. But perhaps little beads on a fluke could bring about some kind of laminar like flow that would reduce friction .............?

Call it a wild guess but I'm betting on smooth surfaces. With anchors I don't think it's difference worth much discussion. But race cars were once teardrop shaped.
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Old 04-23-2016, 11:32 AM   #432
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The Mythbusters covered a cars body in dimples similar to a golf ball and determined it was more efficient. Perhaps someone should try the same with an anchor?
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Old 04-23-2016, 11:45 AM   #433
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Here is my test of the 33 pound Bruce COPY from way back in November. This anchor failed to fully set whereas the GENUINE Bruce of the same size set perfectly. At the time, I attributed this to the fact that the COPY anchor was a different SHAPE than the genuine one.

I no longer have access to the copy anchor but I do recall (and did mention in a later video) that the anchor had been coated with a very bumpy textured paint.

In light of my more recent findings, I believe this copy Bruce anchor's inability to set was hampered to some degree by the bumpy finish.

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Old 04-23-2016, 11:49 AM   #434
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The Mythbusters covered a cars body in dimples similar to a golf ball and determined it was more efficient. Perhaps someone should try the same with an anchor?
Tell that to the truck dealers in Texas...

I knew guys who would drive over to Texas after a good hail storm and get super deals on those dimpled trucks. You would think they would be more with a higher estimated mileage rating...
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Old 04-23-2016, 12:29 PM   #435
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The Mythbusters covered a cars body in dimples similar to a golf ball and determined it was more efficient. Perhaps someone should try the same with an anchor?
Craig,
That's it .... posoblilties.
But what are the odds?
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Old 04-23-2016, 12:36 PM   #436
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As I recall in 1960's... close tolerance "stippled-surface" effect was tested on speed boat hull bottoms (100 mph plus boats). Results were mixed. Item I read on it was that although the stipple surface seemed to slightly improve takeoff and add minor to top end speed... the bad thing was that boats at that high of a speed were more likely to launch out of character due to waves and wind under hull, because the water to smooth hull suction effect had been compromised.
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Old 04-24-2016, 08:05 AM   #437
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The Mythbusters covered a cars body in dimples similar to a golf ball and determined it was more efficient. Perhaps someone should try the same with an anchor?
Different strokes Craig. Only applicable when the surface is traveling through a 'fluid' medium, like air or water. Hence the reduced surface friction of the golfball, also sharks' skin, and even good old Dennis Connor, during the challenger finals of the AC in 1987, who coated his dog of a boat with 3M dimpled coating before the sail-offs at Fremantle, and managed to beat NZ's KZ7 for the first time, the rest being history.

Would not help in sea bottom penetration, but would result in a dirtier anchor coming up. I'm sure for anchors, smooth is the way to go, but buggered if I'd pay the extra for stainless all the same.
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Old 04-24-2016, 08:56 AM   #438
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Here's a question to ponder - What if planing mono hulls from 30' and above could have 25 to 30 percent of its water-friction-to-boat-bottom removed, yet still have nearly exact same foot print in water and therefore same buoyancy? There may be an added weight factor of some thousand plus pounds for the friction reduction equipment to be carried.


Basically, I'm wondering what a 20 to 30 percent water-friction-to-boat-bottom reduction would accomplish regarding gained speed and reduced fuel cost.
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Old 04-24-2016, 09:54 AM   #439
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Art,
Most resistance on even medium faster boat speeds is wave making .. not skin friction.

On Willy it would be a max of 5 - 10% reduction in fuel burn. So I'd be burning .85 to .9 gph instead of one gph. IMO

Peter,
Dimples maybe less friction. Buttons no. Prolly both bring up more mud. But who knows? I think you're chances of getting Steve to test buttons and dimples is about 200-1. However preliminary testing could possibly be done at low tide by hand. Got anything to do today?
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Old 04-25-2016, 04:34 AM   #440
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Should sharp(ish) dig in/cut in edges be kept sharpish? Careful filing when necessary?
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