Anchor for a rocky bottom

[Donald Tyson]

What anchor would you trust on a rocky bottom anchorage?

 

[Bmarler]

I avoid rocky bottoms whenever possible, but if I had to choose one I think I’d use a forfjord. Primitive design, hard to bend or break.

 

[Donald Tyson]

I was wondering if the old style Kedge (admiralty) is used anymore?

https://www.go2marine.com/item-images/543046-Seattle-Forging-Kedge-Anchor_00.jpg?fcts=20210923021258&resizeid=2&resizeh=191&resizew=191

 

[BroadCove]

What type of rocky bottoms? Is it ledge? Coral? Cobble? Different types? Fwiw, I've used my rocna Vulcan successfully over ledge, cobble, and hard pan (shark river in the everglades).

 

[Donald Tyson]

i’m still learning about these definitions. I would assume that ledge would be like up in Maine where the rock is clean and horizontal. And I would imagine that coarse River bottoms of smaller aggregate the size of riprap is what you’re calling cable? Either way I know I would never have trusted the many Danforth I’ve had. And I doubt that a plow would do well. And not knowing what I’m talking about in the first place I just assume that a header would be best.
I’m looking to learn here

 

[BroadCove]

Yes, ledge (in New England anyway) is large pieces of rock, usually granite or similar. For that surface, the anchor doesn't dig in, it just hooks...sometimes with little luck, or if it does, then with little luck retrieving as the anchor gets wedged in. Not a bottom I would anchor over.

Cobble(stones) is different; depending on the size of the stones, a plow-type anchor if heavy enough can get purchase.

In my experience, most anchorages are labeled as such because the ground is decent for anchoring - sand or clay/mud or weeds - and if ledge, for instance, most use a mooring or move on.

The only place I didn't really have a choice was in the everglades, and a recent storm had washed the soft stuff away. I didn't dive on the anchor - peaty water + alligators + crocodiles - but I'm pretty sure I caught a crack in the limestone river bed. It sounded horrendous when the tide shifted in the middle of the night. I thought I was dragging, but it was just the chain dragging over the rock.

 

[Donald Tyson]

Somehow the auto spell changed the word Kedge to header in my post up above. I’ve read about the Kedge anchor which has the picture book style flukes way out wide and a perpendicular crossbar at the top to make the anchor dig in. I’ve heard this anchor works well for cobble and also where legal is weed beds. I read about people in cruising boats anchoring around North Scotland and areas along the UK coast and they are basically anchoring in solid rock. Well, at least one occasion the kedge anchor was used.

 

[Jeff F]

I read about people in cruising boats anchoring around North Scotland and areas along the UK coast and they are basically anchoring in solid rock. Well, at least one occasion the kedge anchor was used.

They may well still champion the CQR around there. I think it's an OK anchor in that stuff.

I'd call your kedge anchor a fisherman's anchor, and see them very occasionally. If you're going to carry three or more anchors this could be one of them.

The modern anchors are remarkably good. I trust my Rocna more than I've trusted any other anchor, but on rock all bets are off, especially with wind/current change.

Where are you cruising?

 

[BruceK]

SARCA abbreviates "Sand And Rock Combination Anchor". Of the Super and Excel models the Super Sarca with sliding slot,to change the retrieve direction pull, might be better in rock.

 

[Mac2]

Whatever anchor you end up with, I would make sure to attach a line/bouy to the anchor when anchoring in rock. This will allow you to pull on the anchor from the opposite direction if the anchor gets wedged in the rocks.

 

[Donald Tyson]

Yes indeed. Thanks.

 

[Mac2]

As a side note, I have a 3 piece luke anchor just for rocky conditions. I have never used it and the thought of deploying it is daunting (around 80 lbs). It could be an option for you though.

 

[mvweebles]

Steve Goodwin of SV Panope, widely recognized authority on anchor types, routinely tests anchors on a cobble bottom field. Attached is one of his summaries. His YouTube channel is very interesting (in a wonky/nerdy way) and must-view material when selecting an anchor.

SV Panope

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m.youtube.com

Peter

 

[Donald Tyson]

As a side note, I have a 3 piece luke anchor just for rocky conditions. I have never used it and the thought of deploying it is daunting (around 80 lbs). It could be an option for you though.

Yes. Yes indeed. This is the anchor I had hoped someone would jiggle my brain for. I could not find it online. For my little 22 foot c-Dory I could use a much smaller Luke. I think Fortress made one for a while. It all folded up into a bag and wait about 10 pounds.
Thank you so much

 

[Donald Tyson]

Steve Goodwin of SV Panope, widely recognized authority on anchor types, routinely tests anchors on a cobble bottom field. Attached is one of his summaries. His YouTube channel is very interesting (in a wonky/nerdy way) and must-view material when selecting an anchor.

SV Panope

Share your videos with friends, family, and the world

m.youtube.com

Peter

Peter, someone had mentioned this author earlier and I lost his name and location as well. I went to see if he had done any research on the Luke anchor.
I don’t know much about anchoring in cobble or stone, but I suspect it will happen some afternoon in Maine or in Canada. Might only use this type of anchor once in a lifetime but it’s one I think I should have on board.

 

[mvweebles]

Peter, someone had mentioned this author earlier and I lost his name and location as well. I went to see if he had done any research on the Luke anchor.
I don’t know much about anchoring in cobble or stone, but I suspect it will happen some afternoon in Maine or in Canada. Might only use this type of anchor once in a lifetime but it’s one I think I should have on board.

Be careful what you wish for. I anchored at a delightful small anchorage off an island on Mexico Central Pacific coast. A rocky bottom was noted in the cruising guide. Turns out I indeed fouled my anchor (Vulcan) as it caught fast on a rock. I tried all manner of twisting and turning to reverse the pull direction with no success. Fortunately a young cruiser nearby came over in his kayak and dove on it and freed it easily. He got a 6-pack of Stone IPA, I didn't have to get wet. Art of the deal......

My takeaway is the type of anchor mattered less than the fact I did not drop an anchor pennent from the eye on the forward shank. Would have been invaluable had I not been rescued by the food hearted fellow cruiser.

Peter

 

[Mac2]

Yes. Yes indeed. This is the anchor I had hoped someone would jiggle my brain for. I could not find it online. For my little 22 foot c-Dory I could use a much smaller Luke. I think Fortress made one for a while. It all folded up into a bag and wait about 10 pounds.
Thank you so much

Fortress is a completely different anchor than a Luke. I had the small Fortress, that comes in a bag, for my last dinghy. It is great in mud, but I wouldn’t use it for rocky conditions.

 

[Discoverer]

For a rocky bottom anchorage, I would trust a Danforth or Fortress the least and a grapnel, Rocna, or Spade the most, depending on the conditions.

If the bottom is truly rocky with large crevices, a grapnel anchor can be a great choice because its prongs can hook onto rocks, but it can be challenging to retrieve if it gets stuck, so will need a trip line.

If the bottom has a mix of rock, mud, or gravel - Rocna, Spade or similar new-generation scoop anchor can perform well. These anchors rely on their ability to penetrate and hold in various bottom types, and they have a broad fluke that can find purchase in gaps between rocks or in patches of softer material.

Bruce/Claw – while not as good as the Rocna a Bruce can sometimes work on rocky bottoms by wedging into crevices. However, it may struggle to reset if it gets dislodged.

Danforth-style anchors including Fortress rely on burying themselves in sand or mud, making them very poor on rocky bottoms. They will likely not set at all.

I personally had a bad experience with Danforth anchors and stop used them completely.

No anchor is perfect for rocks, so a second anchor and a trip line with a retrieval buoy are smart precautions in case the anchor gets stuck.

 

[Jeff F]

I don’t know much about anchoring in cobble or stone, but I suspect it will happen some afternoon in Maine or in Canada. Might only use this type of anchor once in a lifetime but it’s one I think I should have on board.

I've anchored all over Maine and Canada, and have never had an issue finding mud or sand to anchor in. A good depth sounder gives insight into bottom conditions, and even in hard rock areas there are almost always patches of sediment to be found.

The only time I've had issues with my Rocna was in the Bahamas and keys when anchoring in thin sand over limestone. Maybe a different anchor would give better service in those conditions, but more times than not it's easier to try a different spot than it is to swap anchors.

ETA: I can think of one occasion when I had genuine need for a kedging anchor. I ran up on a pile of rocks in Georgian Bay and tried to use my Fortress to kedge off. That anchor came up seriously bent out of shape.

 

[Mako]

If you’re talking about anchoring in large rocks, boulders, then “the best anchor” is very different.

Reminds me of anchoring off of Catalina Island.

I would recommend any very cheap throwaway anchor. Use nylon rode and a trip line, but there’s still a chance it might not be retrieved. Back in the day, I used old Danforths I bought from Doc Freeman’s. They would jamb into a crevice and get stuck.

 

[guy with a boat]

Peter, someone had mentioned this author earlier and I lost his name and location as well. I went to see if he had done any research on the Luke anchor.
I don’t know much about anchoring in cobble or stone, but I suspect it will happen some afternoon in Maine or in Canada. Might only use this type of anchor once in a lifetime but it’s one I think I should have on board.

I think you would need that anchor 0 times in your lifetime. Put a good, modern anchor on your boat and select your anchorages intelligently. Dropping anchor in heavy rocks will result in a lost anchor at some point and is a bad idea for other reasons that will become apparent. Modern anchors will handle cobble.

Metering the bottom and checking your charts is part of selecting an anchorage. Me and every other cruiser I know uses a single anchor and carries some sort of spare that they hope to never need.

I recommend against buying an obscure anchor out of hope that it will work better in a place you shouldn’t anchor in the first place. Take the simple and proven path and, if you still want a “rock” anchor in a year or two (you won’t), get it then.

 

[BruceK]

It may help to explore the SARCA website. It describes the method of retrieval in rock. I had a Super Sarca which didn`t fit the new boat, I bought an Excel which does. Still have the Super Sarca #5 at home adorning the lounge room. Steve/SV Panope liked Sarca anchors.

Super SARCA Anchors - Anchor Right Australia

www.anchorright.com.au

 

[cafesport]

Any anchor with a point should work until that point either breaks the rock or rotates out from under it.
Anchors with two or more points will do better.

I used to teach scuba in Maine and NH in the 70’s. Most of the shallow fouled anchors I came across were Danforth style. I did find several fom the 1800’s that were fisherman style but back then that’s all they had.

I have a grapnel I used to use for wreck diving. With that you need to unhook it manually from the wreck after you tie in.

I would recommend investing in a good bottom finder and spending time learning how to use it. Finding suitable anchor beds is easier than finding the best anchor.

 

[Donald Tyson]

Any anchor with a point should work until that point either breaks the rock or rotates out from under it.
Anchors with two or more points will do better.

I used to teach scuba in Maine and NH in the 70’s. Most of the shallow fouled anchors I came across were Danforth style. I did find several fom the 1800’s that were fisherman style but back then that’s all they had.

I have a grapnel I used to use for wreck diving. With that you need to unhook it manually from the wreck after you tie in.

I would recommend investing in a good bottom finder and spending time learning how to use it. Finding suitable anchor beds is easier than finding the best anchor.

I've read stories over the years where folks found themselves in need of other options. I have a nice Bruce on my new to me 22 footer. The previous owner had taken it off a heavier and larger Key West. It works very well as a general use anchor.

I wouldn't want to be the weakest link. I may never need it and that's fine. But I'll rest better with a well known fisherman or kedge anchor stowed away for a once in a lifetime emergency. I mean of course you will do your very best on a consistent basis to find a good anchorage. Try that with no engine. Try that when the sails or rigging is compromised. Try that when the winds are contrary and the currents are unexpectedly brisk. It sounds to me that some of you may be on much more stable and larger boats where there a more options during dire straits.
I read a story years ago where someone struggled and clawed their way into some terrible and windswept anchorage near northern Scottland. I forget what their troubles were but had it not been for the right rock anchor they'd have been in bad straits for it was a problematically rocky bottom. I believe it was the only time they had used that fisherman's style anchor. It was a multi day blow with ugly currents and nastiness. There were other boats in the vicinity as well and they all had to watch each other as some anchors we drifting.
So I see no harm in having a good rock anchor for protection against that unknown circumstance in some unfamiliar area.

 

[psneeld]

At some point, one runs out of space for anchors that "might" be needed".

Like boats, all anchor designs have compromises.

I looked at what anchor(s) should I carry but which one would be on my pulpit full time. It would have to serve as both an everyday anchor but also one that I could trust to hook on whatever bottom in case of a sudden emergency.

No one anchor is best for any bottom that is not of your choosing (emergency situation).... so you pick the one that is great in most of the bottoms you may cruise over.

Beyond that, depending on what anchor you choose as a primary.... carrying one or two that fit the other extreme bottom types you probably will encounter in your cruises makes sense to me. If one or both could replace your primary if you had to cut it loose also makes sense.

My only answer for the OP would be... depending on exactly what is meant by rocky bottom.... in ANY bottom with snags that may involve hooking the anchor and normal release is not working.... then a trip line needs to be used prior to deploying the anchor. The better anchors for that situation you be super strong and have a pretty wide gap between fluke and stock. Your problem now would be swing and ensuring the rode doesn't foul an exposed fluke and extract the anchor prematurely on some designs (like a fisherman).

 

[Donald Tyson]

They may well still champion the CQR around there. I think it's an OK anchor in that stuff.

I'd call your kedge anchor a fisherman's anchor, and see them very occasionally. If you're going to carry three or more anchors this could be one of them.

The modern anchors are remarkably good. I trust my Rocna more than I've trusted any other anchor, but on rock all bets are off, especially with wind/current change.

Where are you cruising?

Great Loop. I'm inexperienced. But I know everything cause I have the internet. I expect to always find a good bottom. This anchor will be for that once in a lifetime emergency.

 

[Donald Tyson]

For a rocky bottom anchorage, I would trust a Danforth or Fortress the least and a grapnel, Rocna, or Spade the most, depending on the conditions.

If the bottom is truly rocky with large crevices, a grapnel anchor can be a great choice because its prongs can hook onto rocks, but it can be challenging to retrieve if it gets stuck, so will need a trip line.

If the bottom has a mix of rock, mud, or gravel - Rocna, Spade or similar new-generation scoop anchor can perform well. These anchors rely on their ability to penetrate and hold in various bottom types, and they have a broad fluke that can find purchase in gaps between rocks or in patches of softer material.

Bruce/Claw – while not as good as the Rocna a Bruce can sometimes work on rocky bottoms by wedging into crevices. However, it may struggle to reset if it gets dislodged.

Danforth-style anchors including Fortress rely on burying themselves in sand or mud, making them very poor on rocky bottoms. They will likely not set at all.

I personally had a bad experience with Danforth anchors and stop used them completely.

No anchor is perfect for rocks, so a second anchor and a trip line with a retrieval buoy are smart precautions in case the anchor gets stuck.

To me, With only 25' boat owning experience, the Danforth is a Jersey Shore anchor. Hard to catch on rocky bottoms such as the Delaware or Hudson. My bruce seems pretty darn adaptable and it came with the boat.
Just looking for a dedicated rock anchor to store against the day its needed.

 

[Donald Tyson]

My only answer for the OP would be... depending on exactly what is meant by rocky bottom.... in ANY bottom with snags that may involve hooking the anchor and normal release is not working.... then a trip line needs to be used prior to deploying the anchor. The better anchors for that situation you be super strong and have a pretty wide gap between fluke and stock. Your problem now would be swing and ensuring the rode doesn't foul an exposed fluke and extract the anchor prematurely on some designs (like a fisherman).

When I say Rocky Bottom I mean anything that a plow type or Danforth type won't hook well on. A good example would be my beloved Delaware River during Shad season. Its a riprap bottom that is all cemented in with sand and gravel. With the above types they grab a bit....they can't be backed down on or they pull out. I'd be fishing away and all the sudden another boat wake or a shift in stability and the anchor lets loose. The old style Navy anchors don't work either.
Another scenario would be with an engine out being blow toward an obstacle or shoreline and you find it is all flat rock with or without good ledges. The Danforth won't save you.
So those are a few scenario's where a kedge or fisherman may save the day and, as mentioned, with good planning you may never need it. But what would you have on hand if you were stuck out like this....that was my question.
I think we beat this to death pretty well. Now I have to go rescue the folks who were relying on good planning only, lol.

 

[guy with a boat]

…Try that with no engine. Try that when the sails or rigging is compromised. Try that when the winds are contrary and the currents are unexpectedly brisk. It sounds to me that some of you may be on much more stable and larger boats where there a more options during dire straits.
…

I may have missed it, but what boat and anchor size are we talking about? Do you mean an anchor size small enough to deploy by hand and with rode already attached?

I was envisioning an anchor on a windlass with chain and rode. I wouldn’t want to be on the bow wrestling with an anchor change while drifting into the “bad anchorage, no engine, lee shore” scenario. You just have to go with what you have rigged and make the best of it. That’s why I’m a believer in one competent anchor.

If we are talking about an alternative anchor that is hand deployed and already rigged with rode and stored for easy access, then sure, that is a possible option. Changing a heavy anchor on a bow pulpit in bad conditions is probably not going to be your best option.

 

[chanprr]

These posts are very interesting, and in a good way informative. Thanks.
My rule of thumb for anchoring success is to look for soft bottoms. Sonar can give good indications. I have tried rocky bottoms but always had to reset more than once during the night, especially in windy weather. No fun there. So mud or sand is my preference and there is always enough info on the bottom in various guides, such as Waggoner. I carry a Bruce with 300'of chain. The spare is a Danforth.