DIY anchor testing

[GILow]

So a friend, just getting started in sailing and cruising. surprised me the other day with his new anchor. It was sitting on the dock in front of his boat, all shiny and new and looked to be a nice little Rocna. Except there were no manufacturer labels on it. Turns out he had made it himself, based on technical drawings of the Rocna he found online.

Now, he’s a professional metal fabricator and I am absolutely sure it has been made as well, or maybe better, than some production anchors.

But I was still a little dismayed.

My feeling is that there are many subtleties to anchor building and I’ve suggested he use data from SV Panope to check that he is in the realm with tip weight and any other metrics he can find.

I also felt some serious testing would be wise.

The 180 degree rotation used by Steve on SVPanope was the first that came to mind, plus I gave him a short list of local anchorages that will cover sand, mud and limestone bottoms.

But what other tests would be wise?

(Boat is a Northshore 38, so light at under 6 tonnes and very low wind profile.)

Advice welcomed.

Matt

[markxengineerin]

If he will be on board and with an anchor alarm or 2 set up, testing will happen naturally over time until confidence is or is not built up. Hopefully this is the case? But if he's planning to anchor the boat unattended right away, that's a higher risk. I can't imagine that the time needed to sufficiently test it, for the latter case, is a good trade vs. the cost of a new (or even better, used) anchor.

It is cool that he built one himself though, good on him for trying!

[thinwater]

Originally Posted by GILow

So a friend, just getting started in sailing and cruising. surprised me the other day with his new anchor. It was sitting on the dock in front of his boat, all shiny and new and looked to be a nice little Rocna. Except there were no manufacturer labels on it. Turns out he had made it himself, based on technical drawings of the Rocna he found online.

Now, he’s a professional metal fabricator and I am absolutely sure it has been made as well, or maybe better, than some production anchors.

But I was still a little dismayed.

My feeling is that there are many subtleties to anchor building and I’ve suggested he use data from SV Panope to check that he is in the realm with tip weight and any other metrics he can find.

I also felt some serious testing would be wise.

The 180 degree rotation used by Steve on SVPanope was the first that came to mind, plus I gave him a short list of local anchorages that will cover sand, mud and limestone bottoms.

But what other tests would be wise?

(Boat is a Northshore 38, so light at under 6 tonnes and very low wind profile.)

Advice welcomed.

Matt

Excellent questions!


Like Panope, but from a different angle, I've been testing anchors for years. I've decided to weld up an evolution that has always intrigued me, but I've been working trough in my head what testing it would take to convince me it was better.


The beta will be 2.5-pounds , which will make it easy (cheap) to build, and I have a known anchor to test it against (2.5-pound Mantus). It's always good to start with small mistakes. Then I will move up to 8 pounds and so forth, if I see promise. My goal is jam resistance, which is a problem here. The most jam resistant anchors (no roll bar) don't seem to do well in supper soft mud, which I have.

• Static pull is pretty easy. You need an area with a very uniform bottom, preferable one sand and one soft mud.
• A reset test. In fact, like Panope's first test, just flipping them backwards is a good start.

But to me the most important characteristic is reliability on crappy bottoms, and that is something that just take a lot of sets. At least that is what I've learned. The worse the bottom, the more the data becomes scattered, and that's when I worry about dragging.



I'm not doing this to save money or because I planning to invent something important. It's winter, I'm bored, and welding is fun. Anchor testing isn't fun.

[GILow]

Originally Posted by markxengineerin

If he will be on board and with an anchor alarm or 2 set up, testing will happen naturally over time until confidence is or is not built up. Hopefully this is the case? But if he's planning to anchor the boat unattended right away, that's a higher risk. I can't imagine that the time needed to sufficiently test it, for the latter case, is a good trade vs. the cost of a new (or even better, used) anchor.

It is cool that he built one himself though, good on him for trying!

Waking up to an anchor alarm is not a nice way to start his cruising life.

Hence I’m looking for tests he can do BEFORE relying on the thing.

[GILow]

Originally Posted by thinwater

Excellent questions!


Like Panope, but from a different angle, I've been testing anchors for years. I've decided to weld up an evolution that has always intrigued me, but I've been working trough in my head what testing it would take to convince me it was better.


The beta will be 2.5-pounds , which will make it easy (cheap) to build, and I have a known anchor to test it against (2.5-pound Mantus). It's always good to start with small mistakes. Then I will move up to 8 pounds and so forth, if I see promise. My goal is jam resistance, which is a problem here. The most jam resistant anchors (no roll bar) don't seem to do well in supper soft mud, which I have.

• Static pull is pretty easy. You need an area with a very uniform bottom, preferable one sand and one soft mud.
• A reset test. In fact, like Panope's first test, just flipping them backwards is a good start.

But to me the most important characteristic is reliability on crappy bottoms, and that is something that just take a lot of sets. At least that is what I've learned. The worse the bottom, the more the data becomes scattered, and that's when I worry about dragging.



I'm not doing this to save money or because I planning to invent something important. It's winter, I'm bored, and welding is fun. Anchor testing isn't fun.

Yeah, data is king. So your summary is do LOTS of whatever tests we can dream up?

[noelex 77]

If you are able to observe the anchor underwater (either by diving or via video), the distinction between effective and ineffective designs becomes readily apparent.

[SailingHarmonie]

Originally Posted by thinwater

But to me the most important characteristic is reliability on crappy bottoms, and that is something that just take a lot of sets. At least that is what I've learned. The worse the bottom, the more the data becomes scattered, and that's when I worry about dragging.

To me, scattered data tells me more about the bottom than about the anchor. In the real world of cruising an anchor which sets on a "crappy bottom" 50 times out of a hundred is not really any more useful than one which sets 30 times out of a hundred. The difference is as you correctly note certainly hard to measure, and in my opinion, not worth measuring.

To me, on marginal bottoms all anchors are... marginal. Maybe on a particular mix of sand and gravel one is a bit better than another, but neither is giving me a set that lets me sleep well.

[noelex 77]

Originally Posted by SailingHarmonie

To me, on marginal bottoms all anchors are... marginal. Maybe on a particular mix of sand and gravel one is a bit better than another, but neither is giving me a set that lets me sleep well.

Anchoring can be tricky, when dealing with poor seabeds. But here’s the thing: good ground tackle can make all the difference. A well-designed, large, modern anchor (pick one that’s versatile) can often hold your boat firmly in place, even in areas with marginal substrates. This means you can enjoy anchorages that others might miss out on.

[thinwater]

Originally Posted by SailingHarmonie

To me, scattered data tells me more about the bottom than about the anchor. In the real world of cruising an anchor which sets on a "crappy bottom" 50 times out of a hundred is not really any more useful than one which sets 30 times out of a hundred. The difference is as you correctly note certainly hard to measure, and in my opinion, not worth measuring.

To me, on marginal bottoms all anchors are... marginal. Maybe on a particular mix of sand and gravel one is a bit better than another, but neither is giving me a set that lets me sleep well.

Maybe I was not clear or maybe we will just disagree. There are many areas of the world where most of the bottoms are a little crappy and clean sand or sticky mud less common. In good mud my CQR, Delta, or Bruce are fine anchors. Done.



Panope concluded that a CQR was as good as modern anchors, when it was in the right bottom. The primary advantage of modern anchors--or should be--is better reliability over a range of bottoms. The problem is defining "crappy" within reasonable limits. For example, a good sand bottom with a layer of leaves and stick on top of it from resent storms. One anchor might clog (roll bar), while another penetrates cleanly.