The Offshore Voyaging Reference Site

Q&A: What Size Anchor Should We Buy?

Question: My wife and I have recently sold our 40ft Cambria and purchased an Able Apogee 50 for extended cruising. We were very happy with our 20kg SPADE anchor on our 40 footer and would like to purchase a SPADE for the new boat. At 50 feet and with an unloaded weight of 35,000lbs, we feel like the 30kg SPADE would be on the light side but the 55kg anchor would be overkill. Having used both sizes on your boat, we would greatly appreciate your advice. Despite having a hefty windlass, we are concerned that the 55kg model will be too difficult to manage.

Answer: You have great taste in boats. The Cambria and Apogee are two of my all time favorite designs.

I would go with the 55kg model SPADE. My thinking is as follows:

  1. I’m really not sure why a 55kg SPADE would be harder to handle than a 30kg, given that it will stow on a bow roller. If there is any problem with stowing the anchor in all conditions on the bow roller, that should be fixed with modifications to the roller and/or the addition of a chain tensioning device, whatever size anchor you have. I am not in favor of taking anchors off and stowing them below at sea, or not the best bower anyway.
  2. I am convinced that there is a non-linear benefit to bigger anchors once they get over 100lb. In other words, a 55kg anchor holds and sets way more than 1.8 times better than a 30kg anchor.

There is the drawback of more weight on the bow. But there is a way around that too: If you go up to Acco Grade 70 chain, or possibly G40, you can safely go down to 3/8″ and get a substantial weight saving that will more than compensate for the extra weight of the anchor. If your current chain is not G70 or G40 and is only BBB or Proof Coil and is only 3/8″ or less it is, in my opinion, too light anyway.

Note that with G70, you will need to order the chain with custom oversized links each end so that you can get a strong enough shackle to attach. With G40 you can use Crosby alloy shackles without compromising the overall system strength. I would recommend at least 300′ of chain. Of course this will probably let you in for a new windlass wildcat to fit the chain.

All of this could involve you in quite a lot of work and expense; however, I would still recommend it since there are few things that will contribute more to your cruising enjoyment and security than a really bomb proof anchoring system. That was certainly the case for us when we upgraded to the 55kg SPADE.

One other option would be to look at the Rocna line of anchors, which are very like the SPADE and seem to work as well. If you just don’t want to go to a 55kg SPADE, they have a 40kg model.

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