Anchor Sizes
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Nomad Willy
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Bigger is better has always been popular.
I’ve heard many times boaters and airplane pilots have much in common.
The thing that sticks ot the furtherest is their conservatism. That thought is frequently reinforced by anchor talk. Bigger is better (as in very obvious) and I sleep well at night ect ect.
Most of my anchors have been under 15lbs. But I’ve had/used a 22lb a 16lb and a 35 lb once. In all my anchoring I’ve never dragged. I think I started down this path trying out a new gen anchor called an XYZ designed by an Eastern European. I anchored in a 50 knot gale (forecasted) in Allison Harbour. It blew about that for two days and all was well. No drag. but no change in wind direction either. My XYZ was all SS and 13lbs. Boat a Willard 30 at 17,000lbs.
My overall habit was to set hard and usually about 3-1 scope. That’s why I said earlier “it’s not the weight but the design”. But we all start out having little experience and a few opinions eager to adopt old skippers experience and opinions. It’s easy to do. Match the opinions w the numbers and embrace your new standards.
I’m actually not trying to convince skippers to use small anchors. It is less safe. But it is relatively safe to repeat something you’ve already done. The odds of being safe go way up and continue to ascend (but in much smaller numbers).
I did need to shorten scope one night in Ire Inlet as we swung into a rock. I took up some rode out on the bow in the moonlight in my shorts. I used longer scope caving to my TF friends saying my 3-1 was just stupid. I did use about 5-1 in gales.
Next time you’re tempted to order one size bigger think that anchor manufacturers post as appropriate size for your boat is anything they like .. or what they feel will keep them safely out of the courtroom. What they recommend is entirely up to them. They could call out a size bigger just on the mindset is bigger is better. The decision is often not objective however some numbers may be part of it.
Getting back to bigger is better it can happen several times. Manufacturer to dealer, buyer, buyer reads TF .. reads bigger is better and buying a used anchor one can go up a size. Or lastly a new skipper can drag his anchor run to the store thinking about getting a bigger anchor. His dragging probably was the result of some variable not related to the anchor. The seafloor, wrong scope, tide change, ect ect.
There is a best size of anchor for every boat and condition. But to address all these variables would be impossible. So you’ll never know. But one can come close or maybe be right on. Like anything tho you’ll gain more and more confidence. And in time nobody could argue w you if you were to say you have the best size for your boat and area.
But design is more important than weight. However most newer anchors are at least very good.
I might add that anytime you bend an anchor it will be weaker. A good time to re-size. Kind of like repowering and opting for less or more power. Since so many trawlers are overpowered installing a smaller engine may be a good option since it will cost little to change in a repower. There’s a good time to buy a smaller or larger anchor too.
I’ve heard many times boaters and airplane pilots have much in common.
The thing that sticks ot the furtherest is their conservatism. That thought is frequently reinforced by anchor talk. Bigger is better (as in very obvious) and I sleep well at night ect ect.
Most of my anchors have been under 15lbs. But I’ve had/used a 22lb a 16lb and a 35 lb once. In all my anchoring I’ve never dragged. I think I started down this path trying out a new gen anchor called an XYZ designed by an Eastern European. I anchored in a 50 knot gale (forecasted) in Allison Harbour. It blew about that for two days and all was well. No drag. but no change in wind direction either. My XYZ was all SS and 13lbs. Boat a Willard 30 at 17,000lbs.
My overall habit was to set hard and usually about 3-1 scope. That’s why I said earlier “it’s not the weight but the design”. But we all start out having little experience and a few opinions eager to adopt old skippers experience and opinions. It’s easy to do. Match the opinions w the numbers and embrace your new standards.
I’m actually not trying to convince skippers to use small anchors. It is less safe. But it is relatively safe to repeat something you’ve already done. The odds of being safe go way up and continue to ascend (but in much smaller numbers).
I did need to shorten scope one night in Ire Inlet as we swung into a rock. I took up some rode out on the bow in the moonlight in my shorts. I used longer scope caving to my TF friends saying my 3-1 was just stupid. I did use about 5-1 in gales.
Next time you’re tempted to order one size bigger think that anchor manufacturers post as appropriate size for your boat is anything they like .. or what they feel will keep them safely out of the courtroom. What they recommend is entirely up to them. They could call out a size bigger just on the mindset is bigger is better. The decision is often not objective however some numbers may be part of it.
Getting back to bigger is better it can happen several times. Manufacturer to dealer, buyer, buyer reads TF .. reads bigger is better and buying a used anchor one can go up a size. Or lastly a new skipper can drag his anchor run to the store thinking about getting a bigger anchor. His dragging probably was the result of some variable not related to the anchor. The seafloor, wrong scope, tide change, ect ect.
There is a best size of anchor for every boat and condition. But to address all these variables would be impossible. So you’ll never know. But one can come close or maybe be right on. Like anything tho you’ll gain more and more confidence. And in time nobody could argue w you if you were to say you have the best size for your boat and area.
But design is more important than weight. However most newer anchors are at least very good.
I might add that anytime you bend an anchor it will be weaker. A good time to re-size. Kind of like repowering and opting for less or more power. Since so many trawlers are overpowered installing a smaller engine may be a good option since it will cost little to change in a repower. There’s a good time to buy a smaller or larger anchor too.
Last edited:
rslifkin
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I absolutely agree that design matters. A lot. That's shown pretty clearly in the test videos SV Panope has put out with how dramatic a difference there can be between 2 anchors of the same size in the same seabed.
In my mind, the reason to go big (within reason) is for the worst-case scenarios. A heavy anchor will typically get through weeds and other crap on the bottom better, and being oversized will help if you encounter a particularly bad bottom (like cobblestone or soupy mud). Which means less need to swap anchors around for conditions (particularly important if you don't really know what's down there).
And realistically, the difference in weight between "should be adequate" and "definitely good enough for anything I'll need" is pretty small compared to the weight of the rest of the anchor rode, windlass, and the boat in general. I'd rather find some unimportant weight on the boat to remove and leave more weight capacity for useful stuff like spares, batteries, and ground tackle vs trying to over-optimize those in the interest of weight reduction.
In my mind, the reason to go big (within reason) is for the worst-case scenarios. A heavy anchor will typically get through weeds and other crap on the bottom better, and being oversized will help if you encounter a particularly bad bottom (like cobblestone or soupy mud). Which means less need to swap anchors around for conditions (particularly important if you don't really know what's down there).
And realistically, the difference in weight between "should be adequate" and "definitely good enough for anything I'll need" is pretty small compared to the weight of the rest of the anchor rode, windlass, and the boat in general. I'd rather find some unimportant weight on the boat to remove and leave more weight capacity for useful stuff like spares, batteries, and ground tackle vs trying to over-optimize those in the interest of weight reduction.
Nomad Willy
Guru
Size is thought of as weight.
But the real size is in fluke surface area.
Two things will drive the flukes down into the seabed, design of the toe or fluke tip and or weight. Design is far more important. But fluke tips vary a great deal in design. Some are very sharp and others like the Navy anchor and most knock off Claws are not sharp at all .. but anchors work quite well most of the time sharp or not. Design makes the weight and fluke area that’s available do the deed. The Navy anchor rams it’s flukes into the sea bottom but uses much more than it’s heft to do it. Most of the weight pushes down on the flanges that tend to rotate the back of the anchor thus turning the flukes downward and penetration takes place. Kinda like Danforths and the palms at the back. But at a higher level. Great example of how design and mass working together get the job done.
Other anchors like Danforth and Fortress penetrate depending almost 100% on the very sharp fluke tip. And there are anchors that depend largely on mass .. like a mushroom anchor.
But most modern anchors have anchors are more dependent on a sharp toe controlled largely by the aft end of the fluke, roll bar, side palms or whatever to position the fluke tip to do it’s work and then back the toe or fluke tip w whatever mass it has. The Spade has plenty of mass to “get-r-done”.
After penetration is accomplished it’s mostly up to the anchor assuming the best angle to the seafloor to maintain it’s penetration and fluke angle. Notice the different shank angles of Claw anchors. How much tension can be applied by the rode before breakout largely determines holding power .. depending on fluke surface area. Ultimately holding power is mostly determined by fluke surface area.
But weight plays a big part in performance getting the fluke down in the seafloor.
I haven’t mentioned dependability yet but it’s been my personal observation that the heavy anchors like the Navy anchors are more dependable but the anchors more dependent on design have higher holding power relative to their weight.
Pleasure boats being rather small and light lean toward lighter anchors and more directed design to get-er-done.
Mass is easy to obtain whereas design is more important.
rslifkin wrote “ I'd rather find some unimportant weight on the boat to remove and leave more weight capacity for useful stuff like spares, batteries, and ground tackle vs trying to over-optimize those in the interest of weight reduction.”
I agree.
Anchor weight is or should be relative to all the variables that apply.
Hand pulling anchors has real life limits. And if you’ve got all or mostly all line rode a 35lb anchor is on the heavy side. But even that is almost too much if you’re anchoring in 85’ of water.
Larger boats and mechanized retrieval ups the usable ground tackle considerably. But over 500lbs of ground tackle may make your boat try submarining in bigger headseas .. and going out of control wallowing w one’s bow stuck rather deeply into the next sea can make a guy look stupid or take his life not to mention others.
There’s no x amount of anchor weight per ton or a given length of pleasure boat listed anywhere so it’s a guessing game. One could shoot for ground tackle weight so that the boat is trimmed right. Bow heavy is not good. Seen numerous pictures of trawlers underway w big bow waves and heavy spray. One trawler is even known to be a wet boat but it’s probably because the engine/s are too far forward IMO.
But unfortunately trimming a rec trawler is not to look at the graph and get a boat to fit. It’s closser to get your buddies down on the float and eye-ball it. Or if skipper john has a 42’ boat and 800lbs of ground tackle and on my 42 I’ve only got 500 .. John says his boat runs fine so my boat is clearly lacking dosn’t even measure up to most rules of thumb.
But I’d say if you are trimmed right your ground tackle probably isn’t too heavy. But that’s a guess.
But the real size is in fluke surface area.
Two things will drive the flukes down into the seabed, design of the toe or fluke tip and or weight. Design is far more important. But fluke tips vary a great deal in design. Some are very sharp and others like the Navy anchor and most knock off Claws are not sharp at all .. but anchors work quite well most of the time sharp or not. Design makes the weight and fluke area that’s available do the deed. The Navy anchor rams it’s flukes into the sea bottom but uses much more than it’s heft to do it. Most of the weight pushes down on the flanges that tend to rotate the back of the anchor thus turning the flukes downward and penetration takes place. Kinda like Danforths and the palms at the back. But at a higher level. Great example of how design and mass working together get the job done.
Other anchors like Danforth and Fortress penetrate depending almost 100% on the very sharp fluke tip. And there are anchors that depend largely on mass .. like a mushroom anchor.
But most modern anchors have anchors are more dependent on a sharp toe controlled largely by the aft end of the fluke, roll bar, side palms or whatever to position the fluke tip to do it’s work and then back the toe or fluke tip w whatever mass it has. The Spade has plenty of mass to “get-r-done”.
After penetration is accomplished it’s mostly up to the anchor assuming the best angle to the seafloor to maintain it’s penetration and fluke angle. Notice the different shank angles of Claw anchors. How much tension can be applied by the rode before breakout largely determines holding power .. depending on fluke surface area. Ultimately holding power is mostly determined by fluke surface area.
But weight plays a big part in performance getting the fluke down in the seafloor.
I haven’t mentioned dependability yet but it’s been my personal observation that the heavy anchors like the Navy anchors are more dependable but the anchors more dependent on design have higher holding power relative to their weight.
Pleasure boats being rather small and light lean toward lighter anchors and more directed design to get-er-done.
Mass is easy to obtain whereas design is more important.
rslifkin wrote “ I'd rather find some unimportant weight on the boat to remove and leave more weight capacity for useful stuff like spares, batteries, and ground tackle vs trying to over-optimize those in the interest of weight reduction.”
I agree.
Anchor weight is or should be relative to all the variables that apply.
Hand pulling anchors has real life limits. And if you’ve got all or mostly all line rode a 35lb anchor is on the heavy side. But even that is almost too much if you’re anchoring in 85’ of water.
Larger boats and mechanized retrieval ups the usable ground tackle considerably. But over 500lbs of ground tackle may make your boat try submarining in bigger headseas .. and going out of control wallowing w one’s bow stuck rather deeply into the next sea can make a guy look stupid or take his life not to mention others.
There’s no x amount of anchor weight per ton or a given length of pleasure boat listed anywhere so it’s a guessing game. One could shoot for ground tackle weight so that the boat is trimmed right. Bow heavy is not good. Seen numerous pictures of trawlers underway w big bow waves and heavy spray. One trawler is even known to be a wet boat but it’s probably because the engine/s are too far forward IMO.
But unfortunately trimming a rec trawler is not to look at the graph and get a boat to fit. It’s closser to get your buddies down on the float and eye-ball it. Or if skipper john has a 42’ boat and 800lbs of ground tackle and on my 42 I’ve only got 500 .. John says his boat runs fine so my boat is clearly lacking dosn’t even measure up to most rules of thumb.
But I’d say if you are trimmed right your ground tackle probably isn’t too heavy. But that’s a guess.
Last edited:
Graeme Walker
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Maybe I wasn't clear. I upgraded from the CQR to the Mantus 85# with the same 5/16" chain and kept the original Muir HR1200 horizontal windlass. I was never happy with that windlass as it was <90 degree wrap and several times jumped off the gypsy, even after replacing the gypsy and chain. I then called it a day and decided to upgrade the entire ground tackle with a Lewmar V3 vertical windlass with 3/8" chain and Mantus 105#. Several times I've been told I have a big anchor, I take that as a complement!
Another thing that rslifkin mentioned, I find it incredible to see large boats, 45+ with 1/2" lines and 8" diameter fenders, looks silly and doesn't do much for protecting your boat. We use the HTM-4 size, 13.5" diameter center rope tube fenders so we can hang vertically or horizontally. Also tie them to the handrails, gave up on the multiple types of hangars, none of them work well enough.
Apologize if I hijacked this thread.
Nick F
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Some time ago the prime cruising guide to the Caribbean was Donald Street´s guide. His message was:
"Some people select the smallest anchor that will do the job. I prefer to choose the biggest anchor that my boat can carry"
"Some people select the smallest anchor that will do the job. I prefer to choose the biggest anchor that my boat can carry"
Nomad Willy
Guru
Something that should be in this conversation is windage.
In northern BC and SE Alaska we encountered little wind while anchoring. There were quite a few exceptions but mostly anchorages were calm.
Very few on TF talk of more than one working anchor. The reason to consider it is that weather reporting is really good now so most of the time one could use a half sized anchor or an anchor w a wider tolerance for unusual sea floors. A SARCA would be a good half size dayly anchor kinda like we call one of our cars a “driver”. The usual go to car. Then we’d use a much larger anchor for windy situations.
This would be very applicable to those w small boats w/o a winch. Hand pulled gear.
About the only anchor chosen here on TF as an OMG storm anchor is the Fortress. A hand pulled lunch hook is basically not applicable to rec trawlers as eating is done under way.
But I think everybody w a bigger boat and a windlass makes a big effort to choose a large high holding power anchor w perhaps some thought given to veering, short scope, weedy bottoms and other unusual sea floors. Of course one could do the same on a small boat w just a smaller working anchor and a stowed away spare.
I think I basically talked myself out of the half sized anchor.
But TFers are such a conservative lot maybe most just choose a clearly oversized anchor to cover all bases. A BIG working anchor for everything. Size matters.
What other considerations have I missed?
Nick F just wrote;
“
"Some people select the smallest anchor that will do the job. I prefer to choose the biggest anchor that my boat can carry".
Nick some skippers get carried away w that thought. On POW Island there was a guy w a boat perhaps a bit over 40’ that had a 500ib Navy anchor on his bow. I was told he lived on the windward side of a small
Island.
In northern BC and SE Alaska we encountered little wind while anchoring. There were quite a few exceptions but mostly anchorages were calm.
Very few on TF talk of more than one working anchor. The reason to consider it is that weather reporting is really good now so most of the time one could use a half sized anchor or an anchor w a wider tolerance for unusual sea floors. A SARCA would be a good half size dayly anchor kinda like we call one of our cars a “driver”. The usual go to car. Then we’d use a much larger anchor for windy situations.
This would be very applicable to those w small boats w/o a winch. Hand pulled gear.
About the only anchor chosen here on TF as an OMG storm anchor is the Fortress. A hand pulled lunch hook is basically not applicable to rec trawlers as eating is done under way.
But I think everybody w a bigger boat and a windlass makes a big effort to choose a large high holding power anchor w perhaps some thought given to veering, short scope, weedy bottoms and other unusual sea floors. Of course one could do the same on a small boat w just a smaller working anchor and a stowed away spare.
I think I basically talked myself out of the half sized anchor.
But TFers are such a conservative lot maybe most just choose a clearly oversized anchor to cover all bases. A BIG working anchor for everything. Size matters.
What other considerations have I missed?
Nick F just wrote;
“
"Some people select the smallest anchor that will do the job. I prefer to choose the biggest anchor that my boat can carry".
Nick some skippers get carried away w that thought. On POW Island there was a guy w a boat perhaps a bit over 40’ that had a 500ib Navy anchor on his bow. I was told he lived on the windward side of a small
Island.
Last edited:
rslifkin
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I think the small and big anchor combo went away when beefy windlasses became common. Then it was easy to use the big one, so the small one was extra weight to carry that could other be put into something better.
SteveK
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Bigger is better, usually, but always, I do not think so.
Like Willy said in our cruising grounds anchorages we usually have calm waters overnight. If the wind is strong from the south we anchor in the lee on the north side bay, we have options.
Current boat I looked at the windage, the weight and the 45lb Bruce anchor and thought the same, that needs to be upsized. But wait, let's go anchor and find out that it works just fine every time. When it does not, then maybe.
Sometimes bigger is just that, bigger.
Like Willy said in our cruising grounds anchorages we usually have calm waters overnight. If the wind is strong from the south we anchor in the lee on the north side bay, we have options.
Current boat I looked at the windage, the weight and the 45lb Bruce anchor and thought the same, that needs to be upsized. But wait, let's go anchor and find out that it works just fine every time. When it does not, then maybe.
Sometimes bigger is just that, bigger.
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