9 Easy Expert Tips for Anchoring a Boat Near Shore

On this page:

1. Check the Weather
2. Measure with Radar
3. Watch Your Swing
4. Tie On To Land
5. Use a Stern Anchor
6. Pay Attention to the Tides
7. Don't Forget Where Your Depth Sensor and Draft Is
8. Plumb the Shallows
9. Keep a Tighter Watch Using Anchor Watch Tools

Check the Weather

The good news about anchoring near shore is you get the best break from wind and weather. But this is only true as long as the weather is coming from the land. Weather awareness is an important habit for any sailing, and it's doubly important when you pick a spot to anchor.

But anchoring close to shore? A big wind shift can drag you on to a lee shore in any conditions, but when you're only a few yards from shore, the danger is far greater.

The good news is that if you expect constant wind and weather, you can tuck up under the shore as long as the forecast doesn’t change. But if it's at all unstable, you should move, or take extra steps to make sure you're protected. Check the local marine weather frequently when you're anchored close in.

Measure with Radar

We find that eyeball estimates of distance from a boat's deck are very deceptive. That boat that looks like it's about to swing into you while you're sitting in the cockpit looks too far away to hit you when you're in the dinghy. Precise estimates of distance are challenging without instruments.

It sounds silly to use your radar on a clear day to set your anchor, but most radars allow you to measure distances with some accuracy. If your chart plotter has a radar overlay, so much the better. If you're close to shore, turn it on and look. Zoom in so the shore shows up on the edge of the screen then use the measuring tool to check the actual distance.

Check the charts, too, but your radar will be more accurate at finding the land.

Don't forget this is an approximation from the location of your radar dome, and the distance won't be accurate to the foot. But it's reassuring to find those trees that looked thirty or forty feet away are closer to a hundred. This trick also works when you're anchored in close company, just remember it's not exact.

Watch Your Swing

If you drop next to land, don't forget that you might swing no matter what the predicted wind and weather is. Wind might die during the night and currents may push you around or you'll drift around. You've got to make sure that your anchor scope is short enough to keep you offshore. And don't forget to include the length of your boat in that calculation.

If you don't know how to calculate your required anchor chain length, or want more information on how much anchor chain to let out, check out my in-depth article here.

It's not just ending up on land you have to watch for. If the water shallows out you don't want your rudder to catch a reef or rock when you swing closer to shore.

Key to this is taking care where to place the anchor, measuring or estimating the distance to shore (or shallows) as best you can so you can't swing into trouble unawares.

Tie On To Land

It's not unheard of to send a team ashore with a long line to tie the boat off to a rock or tree to keep from swinging. In some tight anchorages with wilder winds like the narrow, deep fjords in Patagonia, this may be the only way to secure the boat.

You need an anchor set in the water too, but a line from the boat to the shore will limit your motion and keep you safer from trouble if the weather shifts. This will hold you in one direction which may be uncomfortable in some wind and wave conditions, so take a careful look around and try to imagine your setup in a variety of conditions.

Make sure what you tie too is solid. An old log won't hold a multi-ton boat if the wind picks up, nor will a small tree.

Use a Stern Anchor

Another way to keep from swinging onshore or into the shallows is to deploy a stern anchor. This anchor need not be the size of your regular overnight anchor, a "lunch hook" is generally enough. We keep a small anchor in the stern locker for just this purpose.

If swing space is tight, in moderate conditions a stern anchor will keep you pointed in the same direction no matter the wind shifts and currents. This removes worries about swinging ashore, though there may be some discomfort if the wind shifts behind the boat and waves build.

Take care when stern anchoring if other boats are around. If anchoring close to other boats AND close to shore, check to see other boats are also deploying stern anchors. If they are not, you may not want to use yours since they might swing into you if the wind shifts.

Pay Attention to the Tides

Close to shore, in most places you will also be closer to shallow water. Tidal swings will change the depth, but when half your boat may swing to the edge of your draft limit, even a foot of tide can make a difference.

Tides aren't the same from day to day, or even at either end of the tide cycle in a day. The morning low may be lower or higher than the evening low. Depending on where you are this difference may be as much as a couple of feet between different low tides. If you're only leaving a foot under the keel, this can be a critical difference.

Don't Forget Where Your Depth Sensor and Draft Is

On our boat, the depth sensor is just forward of the keel. With an eight-foot draft, we've offset it to show us how much is under the keel.

But is the keel always the critical depth?

Not always, if your stern has swung into shallow water. You can ground your rudder close to shore. We had this happen to us in a tight anchorage in Sydney Harbour. Fortunately, it was in soft mud.

Keep in mind that the depth shown up by the keel may not be the depth at the part of the boat closest to shore. So know your rudder depth and remember shallows can still cause problems when the instruments say you are fine.

Plumb the Shallows

We keep a handheld depth sensor on board. We've used it to pick our way through shallows and channels, and we use to check the space behind us in tight near-shore anchorages, especially if the water is murky.

You don't need a fancy handheld electronic sensor. A piece of string and a fishing weight can do the same task. Mark the string at your critical depth, jump in the dinghy, then hold one end and drop the sinker overboard back where you might swing your stern to test the depth. If the mark goes underwater before the sinker hits the bottom, you're good. Check a few spots.

Best to do this at low tide, but you can estimate if you check a tide chart and subtract the tidal swing.

Keep a Tighter Watch Using Anchor Watch Tools

We have several anchor watch tools on board. There’s a Maretron DSM250 with a drag function, a handheld GPS, anchor drag functions on our navigation software and chart plotters, and apps on our cell phones. Even our AIS transponder has a drag alarm in its phone App. We've also got hand bearing compass and a pencil.

We don't use all these tools all the time. But when we're anchored tight near shore, we'll use more than one.

Close to shore, it's important to remember where your GPS antenna is on the boat when you set the alarm. One weakness of our Maretron alarm is its "Set Current Location" function. It's very handy for anchor drag, except that it sets the boat’s position to where the GPS antenna is at the stern is at the time you push the button. It doesn't set the "drag circle" from the anchor, it sets it from the stern of the boat.

This imprecision is acceptable when estimating a drag circle away from shore and other boats; an approximation is fine when you can drag a short distance without trouble. When you are closer to shore you don't have the same margin of error.

We compensate by setting drag alarms to trigger at much shorter distances, and will sometimes set a second or third backup in case things change in the night. The App for our Vesper AIS is good for this, as is our charting software, since we can easily set the drag point from the boat's track where we actually dropped the anchor.