Viking's Odin anchor vs Ultra and the original Viking anchor

[Dockhead]

So what is the disadvantage of a bigger anchor? If you anchor in mild conditions will it hold less well than a small anchor? I don’t beloeve it will. It may not fully bury, but so what. It can hold with just the tip buried. Clearly in extreme conditions or in an inferior soft substrate it will hold better, no-one surely disputes that? If there is no disadvantage and only a potential advantage then why not choose the bigger one? Is it one might be worried about an extra 25kg or 30kg on the bow? If so, don’t worry. It’s nothing compared to the 300kg of anchor and chain already there.

Bigger anchors of the same type are easier to set, not harder. There is probably some size beyond which you can't power set a modern anchor in a hard bottom, but I've never experienced anything near that limit. I've used anchors as large as 75kg on my boat and I could set them in all kinds of bottoms with a bit over idle with the main in reverse. The larger they are, of the same type, the sharper and faster they dig in. Fluke area goes up more slowly than weight as anchor of the same type get bigger, so bigger anchors are more dense, exerting more pressure per unit of fluke area. You can really feel that.

The only disadvantage of a bigger anchor is when it doesn't fit in your bow roller anymore, or becomes hard to handle. Your observation about the relationship between anchor weight and chain weight is exactly the point which Dashew makes. I have 330kg of chain on my boat, plus or minus 30kg or 40kg in the anchor is a rounding error.

 

[Zing]

Bigger anchors of the same type are easier to set, not harder. There is probably some size beyond which you can't power set a modern anchor in a hard bottom, but I've never experienced anything near that limit. I've used anchors as large as 75kg on my boat and I could set them in all kinds of bottoms with a bit over idle with the main in reverse. The larger they are, of the same type, the sharper and faster they dig in. Fluke area goes up more slowly than weight as anchor of the same type get bigger, so bigger anchors are more dense, exerting more pressure per unit of fluke area. You can really feel that.

The only disadvantage of a bigger anchor is when it doesn't fit in your bow roller anymore, or becomes hard to handle. Your observation about the relationship between anchor weight and chain weight is exactly the point which Dashew makes. I have 330kg of chain on my boat, plus or minus 30kg or 40kg in the anchor is a rounding error.

I agree.

 

[geem]

I think the science says that holding power is closely related to fluke area. Weight affects other aspects of anchoring, but not so much holding power.

And "achieving the set", as you say, is the key thing, and that's the "other aspect". Weight of the anchor, and density of it, plays a role there. I have not experienced a situation, ever, where a larger anchor was a hindrance in getting a set. On the contrary, larger anchors exert greater pressure per unit of fluke area, so bite in more easily. ESPECIALLY in hard seabeds. Also, in weed.

Anchors with sharp flukes and clever geometry may be extremely good in that respect. I've used first Danforths, then Fortresses, as kedges for 40 years. In the right conditions the Fortress is amazing, biting in instantly. The Fortress, thrown off the stern, is God's gift to Baltic mooring. I have no experience of the Viking, but Steve's testing seems to indicate it also works like that. The problem with the Fortress, and the reason why no one uses it as a bower, is that it can skip across the bottom, and can pop out in a change of wind direction, and fail to reset. These situations are where a heavier, denser anchor -- imparting a downward vector of force which can engage the flukes in the seabed to get them started going in -- can be a great advantage.

Let us know how you get on with the Viking if you end up trying one.

A ketch rig as you have is a great advantage in anchoring -- raise the mizzen to keep you head to the wind as you settle to the anchor. Do you do that? I have always envied ketch sailors for this. A sloop or cutter will tend to fall off the wind after the anchor is down, which is really annoying.

I don't have an issue with the boat falling off. We very rarely power our chain down. Its always free dropped by releasing the clutch. The only time we would power the chain down was after a particularly boisterous sail when the chain pile in the locker may have fallen over, such that the chain won't easily free drop on its own accord. I don't put the engine in reverse as we drop the anchor as i think it increases the risk of dragging the anchor across the seabed and fouling the fluke, especially in the very often weedy bottoms we see in the Caribbean.
I often throw the wheel over to one side as the chain is free dropping to expose the full windage of the hull so the chain deploys faster.

The mizzen mast alone will keep the boat lying directly into the wind once anchored up. Its far more stable at anchor than a modern high sided monohull. These very noticeably sail around their anchor, particularly when the wind picks up. By comparison, we don't move at all.
I have compared the tip of the fluke on a Rocna with our Spade and the sharpness of the Spade is quite noticeable by comparison.

We were anchored on a hard packed bottom anchored up next to friends with a 40kg Spade on a 47ft sloop, their Rocna was only engaging the tip. There wasn't a full set. We were snorkeling and observed the difference in set between the two anchors. I mentioned this to our friends and suggested they back down on the anchor harder. They gave the engine full revs in reverse, lifting the chain clear of the bottom but the anchor refused to dig in and set any deeper. They simply couldn't achieve sufficient thrust to set the anchor in a hard bottom. They had a 75hp engine.
By comparison, we could fully set the 30kg Spade with our 86hp engine just a few metres away. I know this isn't a scientific study but it's not an unexpected outcome. You need more power to set the blunt instrument than the sharp one. The weight over the tip can only position the anchor for the set, it's the engine than actually sets the anchor as it provides the trust to drive the nail into sea bed much like a hammer.