We like to anchor, whether overnight or just for an afternoon. We prefer anchoring to docking at a marina because it provides privacy and excellent scenery as the boat slowly rotates around with the wind or current. To get to shore, we use the dinghy or kayaks, which are way more fun than walking up the dock.
People choose not to anchor for various reasons. Usually it is because they are afraid the anchor won’t hold and they will go aground or drift into another boat. Consequently, they are unable to sleep at night when they anchor. And they will drag their anchor if they don’t have appropriate ground tackle and follow some basic guidelines.
Ground tackle includes the anchor and rode. The rode can be chain or a combination of chain and rope. Anchor manufacturers provide charts for selecting the right sized anchor for the weight and length of boat. And there are several different types of anchors. Boaters debate which one is best. We have a 55 pound Delta and it has always held, so I think it is pretty good.
There is also unending debate about the best type of rode, whether all chain or a combination chain and rope. There are also various sizes and types of chains from which to choose. Then if you want chain and rope, how much of each? We have 300′ of all chain rode. The chain is 3/8″ BBB galvanized and weighs 495 pounds. Besides having a good anchor set, the weight of the chain helps keep you secure. The anchor is fastened to the chain with a shackle and we also have a swivel that keeps the chain from twisting as the boat swings about.
Fortunately, to raise and lower the anchor we have an electric windlass with controls at the helm, flybridge, and with foot pedals on the bow of the boat.
Protection, depth, tides, currents
Protection is from the wind and wakes, which will make you miserable with waves and constant motion. Based on the weather forecast, we select an anchorage location that will shelter us from the wind overnight. We also try to avoid areas where other boats’ and especially ferries’ wakes would cause us to roll. Depth and tides go together because overnight you will experience a high tide and low tide. Both can ruin your night. Here in the Pacific NW, tides are generally 10-15 feet. Unless you consider the effect of the tide, you may end up aground or adrift. Our boat has a 5′ draft, so obviously if the depth at low tide is less than that, we are aground. If we anchored in 18′ at high tide and failed to consider the 15′ tide change, we would be in trouble at low tide. Conversely, anchoring in 18′ at low tide and failing to account for the depth nearly doubling at high tide could result in your anchor not holding because of an inadequate scope. Finally, we consider currents when selecting a location to anchor. Strong currents put a strain on ground tackle and are generally uncomfortable.
The scope is defined as the length of rode divided by the sum of the current depth, additional depth to high tide, and distance from the water surface to the bow of the boat. Depending on expected wind and current, the scope ranges from 3:1 to 7:1. So if anchored in 18′ with remaining distance to high tide of 4′ and the distance from water to bow of 8′, for a total of 30′, a minimum 3:1 scope would dictate putting out 90′ of chain. For optimal holding in adverse conditions, we would use a 7:1 scope, or 210′. I have painted several chain links a different color every 50′ in order to know how much is out.
Setting the anchor
After determining the location and scope, we position the boat into the wind or current and bring it to a stop. We drop the anchor to the bottom and as the wind carries us backward, we let out the necessary chain/scope. If not enough wind to carry us back, we slowly use reverse. When it is all laid out, it is usually obvious when the anchor catches and sets because the boat stops and the chain tightens. We put a bridle on the chain to take the stress off the windlass and we are done.
When following these rules, the anchor has always held. And we sleep well at anchor.