Upsizing the Fortress for spare anchor

[Marathon1150]

Our Beneteau 11.5 came with an FX-16. Like many other things on the boat when we bought it, that anchor just squeezed into the manufacturer's specs for a boat that size. I prefer over-sized things on a sailboat so we replaced it with a 20kg Bruce and then a Rocna 20. The Rocna never fails. So now we have the FX-16 hung on the pushpit rail for use as a stern anchor and an FX-23 dismantled and stowed for use as an additional or replacement bower anchor.

If I could, I would get a Mantus or a Spade of similar size to the Rocna as well. As noted in a previous post they can be dismantled for storage and I think that they work effectively in a broader range of conditions than a Fortress/Danforth style anchor.

[SV_Lusca]

Originally Posted by Marathon1150

Our Beneteau 11.5 came with an FX-16. Like many other things on the boat when we bought it, that anchor just squeezed into the manufacturer's specs for a boat that size. I prefer over-sized things on a sailboat so we replaced it with a 20kg Bruce and then a Rocna 20. The Rocna never fails. So now we have the FX-16 hung on the pushpit rail for use as a stern anchor and an FX-23 dismantled and stowed for use as an additional or replacement bower anchor.

If I could, I would get a Mantus or a Spade of similar size to the Rocna as well. As noted in a previous post they can be dismantled for storage and I think that they work effectively in a broader range of conditions than a Fortress/Danforth style anchor.

Since you have both, is there a big size difference between them, like you, the Fortress will be left on the pushpit rail. Would you think the FX-23 would be to big for this?

[PineyWoodsPete]

A Fortress question: What is the downside to leaving my FX-11 in "mud" setting (45 vs. 32.5 deg attack angle) + 20' 3/8 chain, for possibly a sand bottom in a Bahamian mooring situation as 2nd anchor when in reversing 2-3kt currents.

Boat 33', 11,000# low profile MC express-type design, upcoming San Fran Bay rivers and Delta cruise, often mud bottom. No extreme weather this time of year, with poss. 20kt winds at times during afternoons, but always overnight in protected anchorages.

I should add that wife and I are now 80, but pretty fit for age, but frequent manual anchor hauling/re-setting is pretty exhausting! Primary is 44# on windlass...

[mikedefieslife]

Originally Posted by PineyWoodsPete

A Fortress question: What is the downside to leaving my FX-11 in "mud" setting (45 vs. 32.5 deg attack angle) + 20' 3/8 chain, for possibly a sand bottom in a Bahamian mooring situation as 2nd anchor when in reversing 2-3kt currents.
Boat 33', 11,000# low profile MC express-type design, in San Fran Bay rivers and Delta, often mud. No extreme weather this time of year, with poss. 20kt winds at times during afternoons, but always overnight in protected anchorages.
I should add that wife and I are now 80, but pretty fit for age, but frequent manual anchor hauling/re-setting is pretty exhausting. Primary is 44# on windlass.

My FX16 has not been any different with the mud flaps on or off. With 1-2m of chain, and variable rode it has still never set even in sand. I can see how it would work in thick mud if you can actually get it to dig in. On my recent attempts if just shovelled the mud up.

Others' milage might vary. When i get around to it, I will be changing mine for something else.

[rslifkin]

The mud palms should stay on all the time. From my understanding, the 45* angle is only for very soft mud, not even normal mud. If it's set to the more open angle and the bottom is too firm, it's unlikely to set properly. So it's better to leave it on the 32* setting and only adjust if needed.

[Stu Jackson]

Originally Posted by Phyrcooler

Interesting that most manufacturers merely provide recommendations based on boat length, and not boat type/potential windage. I wonder if there are any validated tests of the linear pull of various sail and powerboat configurations?

Yes, there are tables in Calder's Cruising Handbook for different size boats in length & beam with loads at different wind speeds.


What one does is use the tables intelligently, often choosing the next sized boat or the same size boats at higher wind speeds to determine what the differences in load might be to size the ANCHORING SYSTEM.


One may often, if not always, find that the size of chain &/or rode will cover those two different table selections, or one chooses to go up one size in chain/rode because it's close.



In engineering, this is called the Use of the Available, and reflects reality of equipment selection based on various load criteria RANGES.


Here's a How To: (the discussions on both pages cover your question)



Anchor System Sizing Tables (Reply #6) & Swivels http://c34.org/bbs/index.php/topic,4....html#msg30400

[PineyWoodsPete]

Originally Posted by mikedefieslife

My FX16 has not been any different with the mud flaps on or off. With 1-2m of chain, and variable rode it has still never set even in sand. I can see how it would work in thick mud if you can actually get it to dig in. On my recent attempts if just shovelled the mud up.

Others' milage might vary. When i get around to it, I will be changing mine for something else.

Well, back in our sailing days on our 37' F-P our FX-16 was totally reliable in a Bahamian mooring situation countless times in over 20,000nm living aboard. But we had a 30' of 3/8" chain on the rode - about 45# worth. Maybe your tiny little length is the problem?

[mikedefieslife]

Originally Posted by PineyWoodsPete

Well, back in our sailing days on our 37' F-P our FX-16 was totally reliable in a Bahamian mooring situation countless times in over 20,000nm living aboard. But we had a 30' of 3/8" chain on the rode - about 45# worth. Maybe your tiny little length is the problem?

Everyone says for these you want as little chan as possible. As the chain is much heavier than the anchor, otherwise you don't get the angle to set it right.

There are few threads about this on CF.

I'll give your suggestion a try though.

[PineyWoodsPete]

Originally Posted by mikedefieslife

Everyone says for these you want as little chan as possible. As the chain is much heavier than the anchor, otherwise you don't get the angle to set it right.

There are few threads about this on CF.

Don't know who "everyone" is, but that's totally counter-intuitive, and counter to my pretty extensive experience. Think about it: with very little chain to hold it down, the stock will tend to lift with tension on the rode and break out the flukes. And the the shorter the line scope on setting, the more the tendency.

Conversely, the heavier the chain, the more the stock will tend to remain tangential to the bottom under the pull to set the flukes.

The fact that you have NEVER been able to set you anchor in ANY bottom pretty much speaks for itself. If your experience was typical, would Fortress still be in business??

[rslifkin]

The "too heavy chain" problem is only an issue at long scope in extremely soft mud. Then the shank can sink below the flukes due to the weight of the chain, which prevents the anchor from setting. In anything firmer, it's not an issue. And if it's not setting due to something like that, shorten scope while setting until it starts to dig in (to limit how far the shank can drop), then let more out after.

[mikedefieslife]

Originally Posted by PineyWoodsPete

Don't know who "everyone" is, but that's totally counter-intuitive....

This is from the Fortress website:

We recommend using 6 ft (2m) of chain for every 25 ft (8m) of water depth. Coastal anchoring is often used in under 50 ft (16m) of water depth, so vessel owners commonly use 10-15 feet (3-5m) of chain with their Fortress Anchors.

Typically, if I'm using a stern anchor I'm in less than 8m of water.

I will try with more chain, but according to Fortress it isn't the answer.

[thinwater]

Originally Posted by PineyWoodsPete

Don't know who "everyone" is, but that's totally counter-intuitive, and counter to my pretty extensive experience. Think about it: with very little chain to hold it down, the stock will tend to lift with tension on the rode and break out the flukes. And the the shorter the line scope on setting, the more the tendency.

Conversely, the heavier the chain, the more the stock will tend to remain tangential to the bottom under the pull to set the flukes.

The fact that you have NEVER been able to set you anchor in ANY bottom pretty much speaks for itself. If your experience was typical, would Fortress still be in business??

Re. Everyone, this advice comes from Fortress.

No, it is not counter my anchor testing expereince. Chain does NOT help with the initial set if you feel it in properly. Heavy chain can prevent setting in very sowt mud by causing the flukes to point skywards.

[Marathon1150]

Originally Posted by SV_Lusca

Since you have both, is there a big size difference between them, like you, the Fortress will be left on the pushpit rail. Would you think the FX-23 would be to big for this?

The FX-23 is significantly bigger than the FX-16. It would probably fit on the rail but it was easier to dismantle it and store it in a Fortress bag inside a locker because the FX-16 was already hanging on the rail.

I just had a quick look at the Fortress website and they provide dimensions here: https://fortressanchors.com/selection-guide/

[Pete7]

Originally Posted by Marathon1150

The FX-23 is significantly bigger than the FX-16. It would probably fit on the rail but it was easier to dismantle it and store it in a Fortress bag inside a locker because the FX-16 was already hanging on the rail.

I just had a quick look at the Fortress website and they provide dimensions here: https://fortressanchors.com/selection-guide/

Agreed, the FX23 is huge in comparison to the FX16. We had problems storing the FX23 under the berths which are divided into water tight compartments in the bow. Sold the FX23 and bought a FX7 for the dinghy. Pointy bits too sharp so bought a Bruce 2kg for the dinghy. The a friend wanted my FX7, so he swapped his FX16 for it. We will stick with it and yes it is neatly stored away in its box under the saloon berths

The 10kg Rocna is the one I normally chuck over the side, you can do that with a small yacht

[noelex 77]

Originally Posted by thinwater

Re. Everyone, this advice comes from Fortress.

No, it is not counter my anchor testing expereince. Chain does NOT help with the initial set if you feel it in properly. Heavy chain can prevent setting in very sowt mud by causing the flukes to point skywards.

This is very true, but it is important to understand that this only applies to pivoting fluke anchors (such as the Fortress, Brittany and Danforth) and then only in very soft substrate such as thin mud where the chain may sink into the substrate and stop the flukes of the anchor opening.

It does not apply to most anchors where a heavier chain will do the opposite and help the anchor develop an initial bite.