Choosing an undersized Rocna Vulcan or correct sized Delta anchor according to guides

[jonase]

I am planning to install a fixed anchor at the bow. Currently in the Nordic part of Europe I am only using a stern anchor and extremely seldom a bow anchor. When I need a bow anchor I have moved my stern anchor to the bow. We are now planning a longer voyage to the Caribbean that would require us to use the bow anchor all the time.

My sail yacht has a length of 11.98meters (39 feet) and a deplacement of 7640kg (16843lb) with a 16kg (35lb) Delta anchor on my stern windlass.

According the the size guides by Lewmar I am using the correct sizing of the Delta anchor. Since I would like to add one more anchor as a fixed bow anchor I am considering other brands as well, especially the new generations of anchors. Have found a lot of positive comments and tests about the Rocna Vulcan anchor.

The challenge is sizing. According to Rocna I should use the 20kg Rocna Vulcan anchor. Unfortunately that is not an option since my bowsprit can only handle a 15kg anchor and the bow windlass only has a 800W motor. I already know that the Rocna size guide is very conservative.

Rocna anchor size guide
Anchor Sizing Guide | Rocna® Anchors

Delta anchor size guide
https://www.lewmar.com/node/11594#specifications

Would you recommend to use an undersized 15kg Rocna Vulcan or using a 16kg Delta anchor that is correctly sized according to the size guides?

[Boatguy30]

I have a 12kg Vulcan. It compares very favorably with larger Spade anchors bases on fluke area.

I would say the 15kg would be just fine. To but into perspective, it will easily out hold a 45lb or maybe even 60 lb CQR in almost all bottoms. 20 years ago, a 45 lb CQR would have been a common choice for that boat.

I guess Rocna likes you to buy so big since they're cheap and Chinese and don't want their reputation tarnished with ANY stories of dragging?

[GeoBay]

We have a 10kg Rockna (roll bar type) on the bow of a 31' sailboat with a displacement of 8500 lbs. On the Rockna sizing chart we were on the upper end for the 10kg. I would have went with the 15 kg but that would have interfered with the bow roller etc. Have been using the Rockna for about 8 years and have NEVER dragged, only once had to retry to anchor as the bottom was like concrete (hard clay) but got it on the second try and was anchored for a few days. In my case I have 50' of 5/16" G4 chain and 250' of 5/8" 8-plait rode and works well for me. In your case the 15kg is close to the 16kg so would probably be fine, but if you could fit the 20 go for it. Not sure about your sailing conditions where you sail such as wind and exposure and bottom conditions.

[John_Trusty]

As has been said many times on this forum, when you choose an anchor imagine your bed and loved ones suspended by a single rope from a tall cliff. Now, what type of rope and anchor do you want? Do you want to sleep well at night?

I am saying this based on having a similar sized / weight boat and choosing a Rocna 20kg. I have been in gale force winds, and have had every confidence that I was going to stay put. That said, I was anchored in sand with almost no swell. Holding in weed or sand-over-rock, and with a high sea, is a different game. If you have only anchored from the stern, you must not be used to anchoring where there is a high sea, so calmer conditions. The Rocna site has the ability to print-out a model that you can make in cardboard and fit to your bow to see if it will work.

By the way, how do you know what the 'rating' for your bow roller is? I have never seen that stamped on anything. Do you think that a 5kg difference will bend it somehow, or the windlass will not pull up your anchor and rode?

[a64pilot]

If your used to anchoring stern and want to continue to do so, I see no reason why you can’t still in the Caribbean.
You’ll get a lot of questions, but so what.
I personally won’t anchor from the stern, but if you want to why not?

My stern has a large flat area, and if there is any significant seas, it slams like a Cat going to windward, and I don’t like slamming.

[jonase]

Originally Posted by John_Trusty

By the way, how do you know what the 'rating' for your bow roller is? I have never seen that stamped on anything. Do you think that a 5kg difference will bend it somehow, or the windlass will not pull up your anchor and rode?

The bow roller will not be an issue. The supplier has rated this for 20kg at their site and also when I talked with their customer service.

The issue is the bow sprit that the bow roller is located on. The bow sprit is only rated for a 15kg anchor and the supplier when I have talked to them don’t recommend using a 20kg anchor on that bow sprit

[billknny]

Originally Posted by jonase

The bow roller will not be an issue. The supplier has rated this for 20kg at their site and also when I talked with their customer service.

The issue is the bow sprit that the bow roller is located on. The bow sprit is only rated for a 15kg anchor and the supplier when I have talked to them don’t recommend using a 20kg anchor on that bow sprit

If you are going to the Caribbean and will be anchoring all the time (or even SOME of the time), your anchor is FAR more important than your bowsprit.

I see that you have a few reasonable options:

• Improve your bowsprit so it can carry a proper sized anchor.
• Figure out some other way to carry a proper sized anchor.
• Stay in marinas every night.
• Get a boat that is actually designed to carry real cruising gear.
• Stay home.

After anchoring most nights for many years, I consider Rocna's tables to be, not conservative, but the minimum a serious cruising boat needs. Anything less you do at your own risk.

You should be asking, "How do I fit an anchor one sized bigger than recommended?"

Anyone who tells you "a smaller anchor is fine" is wrong.

[jonase]

Originally Posted by a64pilot

If your used to anchoring stern and want to continue to do so, I see no reason why you can’t still in the Caribbean.
You’ll get a lot of questions, but so what.
I personally won’t anchor from the stern, but if you want to why not?

;-) Don't think that is an option in the Caribbean. In the archipelagos when I am anchoring with the anchor from the stern the boat is also tied to land at the bow (with the wind direction from land).

[jonase]

Originally Posted by billknny

If you are going to the Caribbean and will be anchoring all the time (or even SOME of the time), your anchor is FAR more important than your bowsprit.

I see that you have a few reasonable options:

• Improve your bowsprit so it can carry a proper sized anchor.
• Figure out some other way to carry a proper sized anchor.
• Stay in marinas every night.
• Get a boat that is actually designed to carry real cruising gear.
• Stay home.

After anchoring most nights for many years, I consider Rocna's tables to be, not conservative, but the minimum a serious cruising boat needs. Anything less you do at your own risk.

You should be asking, "How do I fit an anchor one sized bigger than recommended?"

Anyone who tells you "a smaller anchor is fine" is wrong.

Nice list

The boat is just fine, the issue is not the boat. The issue is that the boat has been used for shorthanded off-shore racing and inshore cruising in the Baltics. It is not equipped for long time cruising, which is about to change.

The list is very long of all the stuff that I need to fix for long time cruising. And I don't have an unlimited budget. I would like to reduce upgrades that are not really necessary. Buying a new bowsprit for 1700$ to fit a 20kg anchor instead of a 15kg anchor was something that I wanted to avoid. I have also had the recommendation to upgrade the windlass to a 1000W/1200W windlass for the 20kg anchor to replace the existing 800W windlass. This would add another 1400$.

The total cost excluding my labor for the difference of a 15kg and a 20kg Rocna with that calculation would be around 3000$.

Maybe this is one of the things that I should prioritize over some other upgrades...

[John_Trusty]

This is not the ideal solution, but perhaps a work-around. Consider two anchors, one mounted on your bowsprit for short-term, low-risk anchoring - you already own this one. The second is a new Rocna (or other new generation) at 20 or 25 kg for serious holding. Carry this off the bow (low, on centerline) and manually rig it when needed. I suggest a bridle ready-rigged, and extra chain as well. This arrangement gives you the advantage of a spare anchor, and a larger anchor for those "oh ****" situations.

The downside is that it is often difficult to tell normal cruising from "oh ****", and normally when it starts blowing "oh ****", you do not want to walk to the bow with 50 kg of stuff to re-anchor! Also, how do you get that 25kg + chain up if your windlass will not handle it?

[kmacdonald]

Get the 15 kg Rocna and a big Fortress FX23 anchor for the heavy holding wind conditions .

[jonase]

I did some more research on the windlass. It will handle the 20kg anchor and the chain since this specific model is more low geared than similar windlasses. Slower but stronger. Which means that I don’t need to replace the windlass when using a 20kg anchor

The 20kg bow roller would fit on the existing bowsprit, but the stay of the bowsprit is not designed for a 20kg anchor. The company that makes the bowsprit has a Code 0 upgrade of the bowsprit, which is basically a new stronger stay with a better fastening for the stay to the boat. I would most likely also have to reinforce the frame on the bowsprit holding the bow roller as well. This upgrade would add up to about 550$ plus the cost of reinforcing the frame on the bowsprit holding the bow roller

[KRMS]

You could elect to use grade 70 chain and go down a size to reduce load on the windlass

[S/V Alchemy]

You are discussing not the right anchor, but the wrong bowsprit. Solve that first to accept the properly sized anchor. Irrespective of the type of anchor, I would always upsize the anchor from the "recommended" values due to my habit of mind, my windage and the fact I'm going to be in a variety of wind-prone places and often alone. Just my two cents.

[Mahayana]

Originally Posted by billknny

If you are going to the Caribbean and will be anchoring all the time (or even SOME of the time), your anchor is FAR more important than your bowsprit.

I see that you have a few reasonable options:

• Improve your bowsprit so it can carry a proper sized anchor.
• Figure out some other way to carry a proper sized anchor.
• Stay in marinas every night.
• Get a boat that is actually designed to carry real cruising gear.
• Stay home.

After anchoring most nights for many years, I consider Rocna's tables to be, not conservative, but the minimum a serious cruising boat needs. Anything less you do at your own risk.

You should be asking, "How do I fit an anchor one sized bigger than recommended?"

Anyone who tells you "a smaller anchor is fine" is wrong.

+1
Save $€£¥ on other things. Ground tackle is where you want to outspend your neighbors.