Knowing how to anchor a boat is one of those essential skills that every captain should master. Even if your boating expeditions start and end at a marina slip, there can be situations that call for dropping the anchor. Maybe you want to stop for a while at a pleasant spot just offshore and have a picnic lunch. Or there may come a day when your engine quits unexpectedly, and you need to secure your boat’s position before it drifts into rocks or another boat.
The steps required to bring a boat to anchor are fairly simple. But there’s a knack to it, and that can be learned only by practice.
The first step is to know the different kinds of anchors. Most smaller boats use the Danforth or fluke anchors. Usually made of galvanized metal and weighing up to 200 pounds, these anchors are designed to drop to the bottom and have the twin flukes dig into the surface material on the bottom.
Larger and heavier boats may require the heavier plow or Delta anchors. When dropped, these anchors fall on their sides, and when tightened, the plow shank digs into the bottom surface. The plow shape enables these anchors to re-set if the wind or tidal conditions change.
Before you anchor
- Know the depth. You need to know the depth of the water where you intend to anchor. To successfully anchor, you need to calculate how much “rode” or “scope” (the chain and line used to attach an anchor to your boat) to let out in order for the anchor to dig into the bottom. If the rode or scope is too short, the anchor may drag along the bottom and not dig in and hold the boat in position. The general rule of thumb is a 7:1 scope ratio – seven feet of rode for every one foot of depth. So if you want to anchor in 10 feet of water, you need to let out 70 feet of anchor line.
- Know the bottom condition. A sandy bottom (like off of your favorite beach) is the best. But here in New England, perfect sandy bottoms can be rare. We have rocky bottoms and bottoms full of seaweed, plant life and often a mix of all three. Getting the anchor to “set” is not always the biggest problem in difficult bottom conditions, it is trying to hoist the anchor up again when you’re ready to leave. Getting an anchor fluke loose from a rocky bottom, or one with old sunken timbers or full of clingy seaweed and such can be tricky.
- Pay attention to wind and tides. When you’re preparing to drop the anchor, you motor slowly into the wind until you’ve reached the point where you want to anchor, drop the anchor, then back down slowly or let the wind push the boat backwards while you let the anchor line out. But the wind can change. Or the tides may shift. And when that happens, the weight of the boat, pulling on the anchor line in one direction, may turn and unset the anchor. Always take a sighting on a fixed point ashore or, better yet, use the GPS function to keep a close check on your boat’s anchored position, in case you start to move.
- Take a bow. There’s a reason why anchor lockers and electric windlasses are located on the bow of your boat. Anchors should only be deployed and fixed to the bow, or front, of your boat. Anchoring off the stern is just asking for trouble. It will pull the stern down and under certain conditions can even swamp the boat from the rear, which is usually catastrophic. Don’t do it.
Experience is the best teacher in anchoring. Once you’ve done it a few times, you develop the knack. And only by getting out there and anchoring can you learn and discover where the “friendly” bottoms are located, and where the wind and tides won’t fight you while under anchor.