Anchor tests

[thataway]

As promised I did tests on multiple anchors on Feb 16. on upper Perdido Bay. The bottom was about 2" of soft non cohesive mud, then 3" of cohesive mud, and finally several feet of combination co-hesive mud, sand and seashells. The air temp was 75 degrees, water temp 64 degrees, clear conditions with a 15 to 18 knots from the East, and minimal waves, since I was about 300 yards from the Eastern shore.

Each pass was in a slightly different place, so that no "disturbed bottom" was used.

The boat is an 18 foot 2003 Century center console, 8' beam, 15 degree dead rise and weight 1800 lbs. The engine is a 2003 115 HP fuel injected Yahama 115 lbs. The prop is 14" diameter x 15" pitch. The WOT RPM is 5500 and speed of 37 knots.

The anchor rode was 9/16" Dacron tow line (designed for drogues, low stretch but suppple). I did not want spring in the test line. No chain was depoyed (mostly to make it easier to get the anchor up) Chain might have helped set the anchor, but would have made no difference in the ultimate holding power.

Method. The boat was brought to a stand still in reverse. The anchor was lowered to the bottom in about 4 feet of water. A PVC pipe was put in the water right were the anchor was dropped. When the anchor was retrieved, the distance from this pipe (amount drug before fully setting) was measured, by the distance of the dug in anchor to the pipe.

After the anchor was on the bottom the anchor rode was paid out until a scope of 7:1 was reached. There was a slight tension on the rode (about 5 lbs) to feel if the anchor was dragging. If it was dragging, the rode was allowed to go slack and then light pressure again applied. When the rode was at 7:1, (including the distance of the cleate off the water), it was cleated off. A second piece of PVC pipe was put in the water and felt to see if the anchor was dragging. If it was dragging, the anchor was attempted to be re-set, or pulled on in slighly jerks to attempt to be set. The wind alone against the boat hull was putting 35 lbs of force on the anchor rode. Once set, the engine was put in gear at 600 RPM idle. The force measured on a spring scale was 100 lbs. If the anchor held at this load, then the throttle was gradually applied to 3600 RPM--this was the max RPM reached with the boat stationary, and the engine all of the way down. Normally the 3600 RPM would put the boat quickly on a plane, and sustain a cruising speed of about 22 knots. I estimated the bollard pull load at over 1000 lbs. Far more than the average boat would achive in winds less than 60 knots. The boat would crab sideways--to 90 degrees. I would take the boat back and re try again at 3600 RPM x 2 more times.

Weight on spring scales, which seem accurate. Fluke area measured, and is some what approximated because of the rounding of fluke edges.

Anchors:
Danforth standard 8 lbs Wt 8 lbs, 46 sq inches of fluke area. This anchor never properly set under these conditions. Just skipped across the bottom

Guardian G7 (cheap fortress)--4 lbs, fluke area 50 sq inches of fluke area,
It dug in and then pulled out at 3:1 scope, but seemed to be holding at 7:1 scope. It slowly drug about 20 feet and pulled out at about 1000 PRM--I estimated about 100 lbs. It would not reset as the boat was drifting.

Fortress FX 16 Wt 10 lbs, fluke area 266 sq inches, in standard position.
Set rapidly did not drag more than 3 feet at 3 runs up to max RPM

Northill Folding Sea Plane SS anchor: Weight 12 lbs, fluke each fluke 154 sq inches. Anchor set promptly did not drag initially. Held up to 1800 RPM and estimated 800 lbs.

Manson Supreme: 25 lb, Fluke area 192 sq inches, set promptly did not seem to drag, held to max RPM with minimal drag--not more than 2 feet.

Delta Fast set 22lb Fluke area 220 sq inches, drug a foot or so, set well, stayed set at full PRM, with about 5 foot total drag.

Danforth 35 lbs(WWII, Cast or forged and riveted crown)--simlar to the High Test or Performance anchor Fluke area 192 sq inches. This anchor set rapidly and did not appear to drag. Held at max RPM. This same anchor held my Cal 46 in 87 knots of wind.

Summary: The Danforth 8 lb did't have sharp enough edges, or was not able to penetrate the surface and did not set. This is a fairly commonly used anchor of the CD 22, and in this test failed.

The Guardian, is too light to pentrate to any depth. Notice that the much larger fluke area, and only 6# more weight FX 16 set well and did not drag.

The Danforth 35lbs is too heavy to be practical--and probably will not fit well on the standard bow puplits, plus no advantage over the other anchors.

The Delta and Manson Supreme were equal in these tests. The Danforth fits the bow roller/pulpit very well, and I put a fast pin thru the crown hole to secure the anchor on the roller. The Manson Supreme does not have a hole which can be used to secure it. It does fit on the Tom Cat Roller. Although they seemed equal, I suspect that in some conditions the Manson would do better. There was more mud on its fluke than any of the other anchors.

Although the Northill is a nice and light anchor, it did fail, and is probably not worth carrying--except on some grass types. I'll probably put mine in the "anchor" musuem-in my garage.

I'll post photos of the anchors tomarrow.

[ppriest]

Assuming the Fortress FX-16 is the adjustable model, which angle setting was used for this test?

Paul Priest
Sequim

[colobear]

Bob,

Thanks very much for doing this test and giving us all the results.

[RJD Wannabe]

Many thanks, always been a fan of the Deltas.

[ccflyer]

Delta Fast 22lb
Best price per google serach
$122.99
http://www.boatersworld.com/product/156780306msk.htm

[thataway]

Paul,
The Fortress FX 16 is adjustable and was set in the "normal" 32 degree setting. The 45 degree or Mud setting is used for "soft" or minimally cohesive mud. I find that in most muds, the 32 degree setting works fine, and the anchor works down into sand or more cohesive layers.

Lacking a strain guage, I had considered using a 100 lb scale and a lever arm to attempt to measure the load on the rode. But after seeing the amount of force which the majority of the anchors held, I reaslized that it was beyond what would be safe with a spring scale and lever arm.

I may pullling with the Tom Cat--and a 1/2" U bolt attatched to the Armstrong bracket. I was watching the cleat very carefully as I was powering up and there was considerable load. I have always backed down in reverse when power setting anchors. The outboards with smaller props are much less effecient than the larger proped, reduction gear diesel boats--so it is hard for me to estimate the exact amount of static pull (Bollard pull). This is why West Marine and US Sailing use large tug boats and heavy duty strain guages when doing their much more detailed anchor tests.

I was surprised that the Delta, Manson Supreme and Fortress did not drag. I had expected at least one of them to, considering the power applied. The Fortress is too bulky (when put together) to be practical as an anchor. The Delta has the advantage of being a bit easier to secure than the Manson Supreme. I suspect that in some instances, that the Manson will set faster than the Delta...

[hardee]

Thanks for doing this testing. That's way over the top C-Brat help you're doing, and it is appreciated. I am still looking, and the Manson Supreme or Rocna are way up on the list. Delta is more practically priced, and is looking better all the time. Thanks again, Dr. Bob. to you.
Harvey
SleepyC

[Dora~Jean]

Great info Dr. Bob, thanks. I happened to have a 22-lb Delta, same one for the past 2 boats, haven't had a problem with any of the conditions and bottoms I've used it on, including over 60 mph winds. It has reset consistently in strong or weak winds shifting 90-180 degs, also in Morro Bay where the current switches 180 degs every 6 hours at 4-6 knots. I bought it originally based on test research articles. We have some bottoms around our islands that are mainly pebbles, 1/4-1/2", the danforth I used to use (16 lb) on a smaller boat just skipped, wouldn't set. The Delta always sets in that same area.

The other popular anchor many folks use is the Bruce. I almost bought that one instead (for my 31ft trimaran), but a boater friend relayed an experience he had which changed my mind 12 yrs ago. He anchored by one of our islands, close to shore, near kelp. When the wind piped up, he began dragging his anchor. Brought it up, had an entire kelp root-ball in its grips! The plow type anchor would be less likely to do that I believe, but haven't experienced that.

Last year at the islands I observed a similar situation, a boat having trouble getting a solid set, he had a bruce, brought up a 'grass ball', roots and all -- clogged the flukes.

Please don't get me wrong, not trying to start a delta/bruce or any other kind of war. Some other owners might have other observations on Deltas, would love to hear them or any other anchoring situation that would be useful to share.

[thataway]

Thanks for the kind words.

Here are a couple of photos of the Delta vs the Manson Supreme on the anchor roller of the Tom Cat 255. I was not able to upload any other photos of the tests for some reason. Notice how the Delta fits the pin and is secured on the roller. The Manson's slot does not line up with any of the holes in the roller pulpit, so it will have to be lashed in place. I know that the Delta clears the hull of the CD 25. The Manson is a bit longer on the "point"--and I won't know how it sits on the CD 25 roller until I take it out there in a couple of months.

Anchor tests are only valid for those types of conditions which the tests are done in--and should not be translated as being satisfactory in other bottoms. I feel that all of the anchors which held would hold a CD or Tom Cat in up to and including hurricane force winds--in these bottom conditions. I have not had good "luck" with Bruce anchors, so I do not use them. There are some "scoop" characteristics, rather than "plow" effects in the Manson--and it may be a good anchor where the bruce is, as well as places where the bruce does not work as well--but this is only speculation.

[Alok]

[journey on]

Bob, that was quite a test. We've had very good luck with the Bruce, both here in So Cal and up in Canada. I'm sure the Manson will work very well.

Regarding the small Danforth not setting, I'm reminded of the first time I want to Santa Cruz Island in the Catalina 22, without much knowledge of boats. As you well know, in most of the harbours there, you have to anchor fore and aft, using 2 anchors. I bought a small Danforth, got some rope and happily set off. Got to Pelicans, set the front anchor, went back threw out the aft anchor, and nothing I did set that anchor. Finally a couple of scuba divers set it for me, by hand. Another learning lesson. I bought 10' of chain for that puppy and, it worked fine from then on.

Also, I looked at the West Marine tests on anchors (2008 catalog on the internet,) and they couldn't get a CQR to set in sand. That's a new one on me.

Boris

[centerisland]

[helm]

Bob, we have a Manson supreme on our CD-25 and it sits just fine on the bow roller. I had to modify the top roller because of the width of the anchor shank, very easy to do and all in all it is a nice rig.
Best
Eric

[dogon dory]

Sorry, Folks - Post Deleted By Author

[Sea Wolf]