See full version: Selection Guide
Note: Hard sand holding power figures above represent loads actually achieved on production Fortress and Guardian anchors under controlled horizontal pull conditions without dragging or resulting in disabling structural deformation. [links]
Use three-strand nylon rope, 6-12 ft (2-4 m) of chain and a minimum of 5:1 scope. Also, a minimum of 6 ft (2 m) of chain should be used for every 25 ft (8 m) of water depth. For storm conditions use an anchor one or two sizes larger. here
Boat anchor size recommendations are for boats of average windage and proportions in 30 knots of wind, average bottom conditions, and moderate protection from open seas. Remember that the loads in 42 knots of wind are twice as much as in 30 knots. more
Mobile users please scroll to the right to find your boat length and anchor model selection.
When sizing an anchor or anchor rode, it’s useful to have starting point and to think of the whole system. This is a table developed by American Boat and Yacht Council (ABYC) to approximate the expected load on the anchor and the anchor rode for given wind speed and boat length. The complete table appears in Section H-40 of ABYC’s Standards and Technical Reports for Small Craft available at abycinc.org. The below table was created more than 50 years ago and it is not clear exactly how it was derived. After comparing this data in this table to work that has been done since we come to the conclusion that the values presented here represent loads expected on the anchor rode if anchored on chain only without the use of the snubbing system. And using a line rode or and adequately designed snubber you can reduce the loads by a factor of 3, by eliminating the shock loads. This is an argument for why its so important to use a snubber but when sizing anchor rode or your anchor, it is important to consider loads as stated in the table. The reason is that we can not rely on the integrity of a snubber in a storm. Should the snubber fail, the integrity of the rode should be sufficient to handle the loads without the snubber.
The ABYC Horizontal Working Load (lbs) Table
How do you intend to use your boat? Do you sail only on calm days with fair weather (Lunch Hook) or are you outfitting for an adventure (Storm) where you might be exposed to hazardous weather at anchor? For example, if you are outfitting a 35 foot boat for you should size the working rode and anchor to safely handle loads up to 1,800lbs if planning a cruising adventure, but the same margin of safety is not necessary if operating day trips from the safety of a marina. here
However, Scope 8:1 for 10 metres of depth = 80 metres total chain and warp and this makes a good benchmark starting point for your final decision.
For long distance Offshore and Ocean cruising you may want to consider increasing the scope to 10:1 on all chain or even 12:1 on a chain/rope combination. This particularly applies to anchorages around some Pacific islands. here
Jimmy Green Marine offer a comprehensive range of solutions from leading brands for all your anchor rode requirements.
Slight Downsize = 20mm Anchorplait Nylon LIROS MBL 8400kg or Upsize = 24mm Anchorplait Nylon, LIROS MBL 11800kg more
Your anchor rode is your primary safeguard when anchoring overnight in a foreign anchorage so aim for the longest and best affordable option, bearing in mind the detrimental effect of your yacht’s performance if you overload the bow with too much weight. here
The generally accepted guide for the length of your anchor rode – An Anchor Rode encompasses Chain, Rope and the all the shackles and connectors – is 8 metres of rode for every metre of depth you will be anchoring in. This is referred to as the scope, in this case 8:1. here
Fluke
Danforth, or fluke-style anchors, are the top choice for most recreational boats with overall lengths of 30' or less. Fluke anchors provide sufficient holding power considering their small size. By design, they fold flat and are easy to stow in storage compartments. The anchor arm, or stock, buries itself after the pointed flukes dig into the bottom. For those reasons, fluke anchors are best in hard sand and mud. The flukes can’t penetrate rocky bottoms and are not recommended for slick, grassy bottoms. Loose mud or clay can foul the flukes and prevent bottom penetration.
more
Bottom conditions
Holding power and weight are only as good as the anchor’s ability to penetrate the bottom. Anchors easily penetrate hard sand bottoms, which offer consistent holding power. You get less in mud, which the anchor must penetrate to reach a harder secondary bottom material. Anchor weight is more important than design in difficult grassy bottoms. more
The language of boating jargon has a logical purpose—shorten phrases into single words of uniformity that can be clearly communicated—and understood—by anyone involved in the navigation or tending to of the vessel.
Mushroom
Ideal for canoes, kayaks and jon boats, the mushroom anchor works best in soft bottoms, where it creates penetration based on suction. Makes a decent lunch hook anchor, but is not recommended as the primary anchor.