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ASA 103 Seamanship

· sailing,ASA103

Describe common anchor types

There are 3 general types of anchors: cement blocks (permanent), burying anchors, and hooking anchors. It is important to use the appropriate anchor type based on the type of bottom you will be burying the anchor.

  • Burying anchors: these include Danforth style anchor (pictured below), which is very common and holds very well, especially in sand and mud. Does not work well in grass, weeds, or if the mud is soft.
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    Other types of burying anchors include Bruce style and Plow style anchors.

  • Hooking anchors: these anchors have a hook that can punch through grass or weeds. These include northhill style, navy style, 

Describe major considerations for anchorage selection

A good anchorage should be protected, have enough room for the boat to swing 360 degrees, have proper depth, and a bottom that is suitable for anchorage.

Describe proper scope for short term and overnight anchoring as as well storm conditions

The scope is the total length of your chain/line/anchor (the entire length is sometimes referred to as the anchor line) relative to the depth of the water + the freeboard height.

If staying for a short stay and someone will remain onboard to monitor the boat, you can use a ratio of 3:1. So if your depth is 7 feet and your freeboard is 3 feet, you should let out 30 feet of anchor line (10ft x 3). If staying overnight, you should use a minimum ratio of 5:1. If unsure about the anchorage conditions, a ratio of 7:1 is better.

More scope will give you better anchorage and reduce your chances of dragging anchor, however you will naturally need more swing room. When calculating water depth, make sure to use depth at the highest possible tide.