The Offshore Voyaging Reference Site

Specifying Primary Anchor Size

JHH5-13428

In the previous chapters we wrote about anchors we like. Now let’s move on to our recommendations for the size and material for our best bower (primary anchor).


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More Articles From Online Book: Anchoring Made Easy:

  1. Introduction
  2. 4 Vital Anchor Selection Criteria and a Review of SPADE
  3. SARCA Excel Anchor—A Real World Test
  4. SPADE, SARCA Excel, or Some Other Anchor?
  5. Rocna Resetting Failures and Evaluation of Vulcan and Mantus
  6. Some Thoughts On The Ultra Anchor, Roll Bars and Swivels
  7. Specifying Primary Anchor Size
  8. Kedge (Secondary Anchor)—Recommended Type and Size
  9. Third Anchors, Storm Anchors and Spare Anchors
  10. Anchor Tests—The Good, The Bad, and The Downright Silly
  11. Making Anchor Tests More Meaningful
  12. We Love The Way Our Anchor Drags 
  13. Things to Know About Anchor Chain
  14. Selecting a Chain Grade
  15. Anchor Chain Catenary, When it Matters and When it Doesn’t
  16. Anchoring—Snubbers
  17. Anchor Rode Questions and Answers
  18. Q&A: Hybrid Rope And Chain Anchor Rodes
  19. Anchor Swivels, Just Say No
  20. A Windlass That Makes The Grade
  21. The Perfect Anchor Roller
  22. Install A Wash-down Pump—And Save Money!
  23. Anchoring—Kellets
  24. Anchoring—Chain: Stoppers, Termination and Marking
  25. 20 Tips To Get Anchored and Stay Anchored
  26. Choosing an Anchorage
  27. Choosing a Spot
  28. 15 Steps To Getting Securely Anchored
  29. One Anchor or Two?
  30. Two Anchors Done Right
  31. It’s Often Better to Anchor Than Pick Up a Mooring
  32. Yawing at Anchor, The Theory and The Solution
  33. Yawing at The Anchor, an Alternative Cure
  34. How To Use An Anchor Trip Line
  35. ShoreFasts—Part 1, When to Use Them
  36. ShoreFasts—Part 2, Example Setups Plus Tips and Tricks
  37. ShoreFasts—Part 3, The Gear
  38. Gale And Storm Preparation, At Anchor Or On A Mooring
  39. Storm Preparation, All Chain On Deck
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Geir Ove

We also like it BIG. and heavy.
We had a 20 kg Rockna for our Lagoon380 and it worked very well, but it did not give me the good sleep at nigth when wind was blowing hard, So i changed it to the biggest i have space for a 33kg Rockna, and setting it well, i sleep very well.
Big is Better.

We also have a Spade 15kg just as an ekstra , what we call an Coffe anchor to just sett out on the back when needed. its so nice as is it just to remove the bolt an flat pack it. 8 meters of chain and then rope, and we use our Mainsail (EL) winch on it. Life is good 🙂

Dick Stevenson

Hi John,
As someone sailing the boat used for you example, I concur with all you have said. I have used the 66 pound SPADE for 7-8 years now and have been very happy. It was the biggest I could get short time, and I have been thinking for a couple of years now that the next size bigger would have been better.
As to weight, the difference is not significant. This is particularly the case if you forgo the many advice givers who put anchor size and chain size together. So the 3/8 or even 7/16 inch chain that many might think would go with this anchor weight can easily be dropped to 5/16 G4 as, in the higher wind ranges, strength of the chain is far the most important criteria when compared to weight. At least that is my take. This gives a big weight savings and the weight goes where it really counts: in the anchor.
Cheers, Dick Stevenson, s/v Alchemy

Fuss

I agree with the comments about weight and penetrating the surface. I am fairly sure that my 60kilo does a much better job of this than the old 34kilo.
The winch should be big enough to pull the anchor up in marginal conditions. You can test if its big enough by doing the following… next time its blowing 18kts, use the winch to slowly pull your boat to the anchor and retrieve it. If it smells or burns out , its too small.
I am sure that on a dark stormy night, it will get alot more stress than that if you decided to retrieve the anchor.
The amount of bow rollers that stick out miles and are very thin is amazing, I only hope they have a snubber that works without the bow roller. I tried to make mine very short and it has small fins so the chain does not have to come in absolutely straight.
The one area that makes me a little uncomfortable with my current setup is that it takes me 1 minute of work to deploy my anchor. I cant do it instantly. I have to give it a small push. I think that if I had a 50kilo then it might be better as 60 is slightly too big.

Charles Starke

Hi John
I had an aluminum Spade on my last boat and it was good and reliable. But I think the aluminum reacted with the zinc on my chain, and one foot of chain rusted severely every year. I kept chopping off chain. Not a good situation.
I would never recommend an aluminum anchor used with chain. I now carry a 44kg galvanized Rocna on a Trintella 47 with displacement about 37,000 pounds. It seems ok so far, but like you, I always question about whether I should have chosen bigger or the Spade (which I loved except for the chain issue. )
Best wishes
Charles
s/v Dawnpiper

Charles Starke

Hi John
We did the typical anchoring- overnight. Nothing long term. I think salt spray also contributes to the zinc reacting with the aluminum. The zinc disappeared regularly and the steel underneath rusted fairly quickly.
I loved the Spade and the aluminum made it easy to carry bigger but I did not like the disappearing chain!
Best wishes
Charles

Terry Mason

Another reason to eschew stainless anchors, chain and fittings: Stainless is bright and shiny due to the oxide film on the surface which, surprising as it might seem, needs oxygen to maintain its integrity. Once immersed in seawater, however, the oxide film cannot be maintained and the SS will soon turn to mush as the bright and shiny deteriorates. Besides, who wants a rusty SS anchor on display at the marina?

Matt

Stainless is nice for frequent short stays in sticky bottoms. (The mud just slides right off a well polished SS fluke.) Other than that, I think galvanized steel is by far the best option. Stronger, more predictable, cheaper, fewer insidious corrosion quirks.