Choosing an Anchorage Part 1

When the day draws to an end, it's nice to pull into a protected anchorage where you can calmly cook a good meal and get a good nights rest!

Short sailing trips tend to involve sailing from one anchorage to another, this means that every night will be spent in designated and well charted anchorages where the conditions are comfortable (or known to be uncomfortable). On the Chesapeake Bay, anchorages tend to be miles up a river or creek. When traveling only by sail, these anchorages can take a good part of the day to reach! This is fine if your destination is the next anchorage, but if you are sailing to a far away destination, these journeys to the anchorages are a waste of time!

On longer sailing trips, traveling 2 hours up a river to reach an anchorage means 4 hours of sailing are lost each day (2 hours to leave the anchorage in the morning, 2 hours to enter the new anchorage in the evening). Over 1 week, this would be 28 hours of sailing time spent entering or exiting an anchorage. As you can see, your progression would be greatly slowed! 

If you can sail all day and begin searching for an anchorage around sunset and reach it rapidly, almost no time is lost while traveling towards your destination. This is where learning how to pick an anchorage becomes an important skill.

When choosing an anchorage, there are several points to consider:

  • Length of time anchored
  • Protection from wind
  • Protection from waves
  • Tides and currents
  • Bottom composition

Length of time anchored plays into how protected you need to be. You don't have to be worried about changing weather conditions if you are anchoring for lunch as much as you do if you are going to anchor for the weekend. The longer you will be on the hook, the more protection you will need. 

If you are anchoring for the night, you will only be on the hook for 7 to 10 hours and will need to find a protected anchorage so you can sleep soundly for the night, waking up recharged!

Protection from the wind is important because wind load will cause strain on your anchor. If your boat is in the face of a lot of wind, you run the risk of the anchor dragging. By staying out of the wind, your anchor is less loaded and will be less likely to drag throughout the night.

Protection from waves is very important for quality of sleep. I don't get sea sick, but I worry that the anchor will drag if we are bouncing around in high seas instead of sleeping soundly. Maddie does get sea sick, and spends the whole night throwing up! For these reasons, protection from the waves is very important!

Tides and currents also come into play when anchoring overnight. It is important to check the tide tables to see if you can expect a tide reversal during the night. Some anchors do better than others with reversals while others run the risk of not resetting. Currents are also important to consider. If you anchor with wind and tidal current in the same direction, this means that after a tide reversal the wind will be opposing the tidal current and the waves will kick up with the boat anchored in a confused set of waters.

Bottom composition is also important. Different anchors work best with different bottoms and matching the anchor you use to the bottom you are anchoring in is very important. The bottom conditions tend to be marked on charts as well. This means that if your favorite anchor is best in mud,  choose a section that is charted as mud to anchor in and avoid hard pack or rock bottoms! If you are unsure of the bottom condition, you can place some bees wax in a sounder, drop it to the bottom (this also tells you the depth) and then pull the sounder back up. A sample of the bottom will stick to the wax and let you know exactly what bottom substrate you are working with.

Now that we have looked at all of these factors individually, it is time to put all of this knowledge together to select your anchorage while sailing along.

Imagine you are sailing along and the day is drawing to an end, it's time to find an anchorage and get there before the sun goes down. If it is a calm night and the weather is going to stay calm, anywhere is fine!

Just because it's calm now and looks like it is going to stay calm, doesn't mean that it will stay calm. Most nights when we anchored in the middle of the bay, we would cook dinner, relax, and go to sleep, all in very calm and still water; it's wonderful! 

Some nights though, late in the evening, the wind and seas would pick up. We have found ourselves anchored out in the middle of the bay with no protection, feeling everything since we were fully exposed.

If you decide to drop the hook in the middle of nowhere, simply check your charts and find someplace with shallower water and a good bottom. Bottom condition is very important when anchoring on these underwater hills because if your anchor drags, it will probably not re-engage the bottom. As you drift, your anchor falls off the top of the hill and into deeper water which relates to reduced scope. 

Say you are sailing by this area and the sun is getting low to the horizon on a calm day. When you look at the chart, you can see various bottom conditions. You have deep water with broken shells, shallower water with hard pack bottom and another shallow area with a sticky bottom. The sticky bottom is on the edge of the depth contour line. When you drop the hook, let out enough rode so that if you do drag over the contour line and into deeper water, you will still have enough scope to re-set. If you drop the hook in 12 feet of water (with a 6 foot high bow roller), your effective depth is 18 feet. If you let out 90 feet of chain, you will have 5:1 scope which is adequate. If you drag into the 16 feet depth, your effective depth becomes 22 feet and the scope is reduced to 4:1. If you were dragging in the 5:1, you will probably continue to drag with the 4:1 scope into the 21 feet deep water and your effective depth is 27 feet with 3.3:1 scope. At this point, your going to continue drifting as your anchor drags all night long! To avoid this, simply let out more rode so that if you do drag into deeper water, you will still have enough scope to re-set once you get there.

When you anchor in 12 feet of water with a sticky bottom for the night, let out 154 feet of chain. This will give you 8.5:1 scope which is overkill, but if you drag into the deeper section, you will still have a 7:1 scope. You won't drag anchor with 8.5:1 scope, but if you do, your anchor will most likely reset quickly in the deeper water.

To decide how much rode to let out, simply look at the deeper sections that you could drag into and let out the appropriate amount of rode for that depth. This will give you the depth to calculate your scope from. In the example above, the deeper sections had an effective depth of 27 feet. 27 x 7 (from a 7:1 scope) gives you 154. This is the length of chain you need to let out, even though you are in much shallower water at the moment.

Next we will discuss anchoring in "not calm" conditions when anchoring out in the middle is not an option but sailing into a distant "well known" anchorage is not feasible.