Tips for Successfully Anchoring a Boat
Anchoring a boat is a skill you’re going to master through practice, trial and error.
Dropping anchor is simple enough, but perfecting it isn’t as straightforward as one may think. For the novice boater, here are some tips to master the skill of anchoring your boat.
Why You Need an Anchor
The law says you must carry certain things such as a life jacket for every person onboard at all times, but what about an anchor? As of this writing, there’s no law requiring a boat to carry an anchor, but common sense should tell you that yes, you should have an anchor onboard at all times.
An anchor is an invaluable piece of equipment for recreational boating. When you’re fishing, an anchor keeps your boat in place so you can, well … fish! If you fancy swimming or snorkeling, an anchor prevents the boat from drifting away. Mooring up or wading ashore to explore a cool spot or stopping for lunch? Yup, you need an anchor for that! You get the point.
Recreational purposes aside, for safety purposes, an anchor is essential to the wellbeing of the boat and everyone on it. If a mechanical issue with the outboard leaves you dead in the water, the anchor prevents tides or currents from dragging the boat into dangerous territory. In emergency situations, anchors keep your boat safely intact until help arrives. Even in foggy conditions with near-zero visibility, the best thing to do is drop anchor until the fog lifts and you can continue on your way.
Never Anchor a Boat by the Stern
It might be tempting to anchor a boat from the stern because of a couple of handy cleats or a lower gunwale (which means less lifting), but don’t do it.
Anchoring by the stern can easily cause the boat to take on water, capsize or sink. The problems with anchoring at the stern are that the freeboard (the distance from the waterline to the top of the hull) is lower at the transom than it is at the bow. The stern is already heavily weighted by the outboard motor or sterndrive, and adding the pull of an anchor and rode (the chain and/or rope that attaches the anchor to the boat) to the stern can lower the freeboard, bringing the top of the transom dangerously close to the waterline. Doing so makes the boat vulnerable to waves that could wash over the transom. An increase in current could also pull the stern below the waterline, so always attach the anchor rode to a cleat at the bow, not the stern.
Don’t Throw the Anchor Overboard
Several things can go awry when you’re putting down the anchor, which is why you should never toss it in.
Anchors are heavy and if you fumble your throw, the anchor can damage your boat’s gelcoat or worse, put a hole in the deck, which will be costly to repair. If the anchor falls on your foot, get ready for a painful trip to the ER! (We hope you have medical insurance)
Slowly and carefully lower an anchor into the water. By lowering the anchor instead of tossing it, you buy enough time to untangle yourself if an arm or a leg gets caught up in the anchor rode. You (and others) can easily be injured and/or dragged overboard. Make sure everyone else onboard stays back when you’re dropping anchor. And of course, wear a life jacket while dropping or retrieving the anchor in case you go overboard.
Throwing an anchor also increases the likelihood of the rode fouling on something or piling into a tangled heap on the bottom. Lowering the anchor keeps the rode tight so it lays out in a straight line across the bottom.
Set the Correct Scope for the Conditions
Scope is the ratio of the length of the rode compared to the distance from the point the rode is attached to the boat to the bottom, as measured in a downward vertical line.
For example, if the length of the anchor rode is 100 feet and the distance from bow cleat to the bottom is 20 feet, the scope is 5:1. If the scope is too large, the length of the rode will be so long that it allows the boat to drift too much. However, if the scope is too small, the length of the rode isn’t long enough to allow the boat to ride waves or move as currents and tides change.
The correct scope varies with weather and water conditions, and also depends on the size and weight of the boat. However, in typical conditions the scope should be about 6:1. So if the distance from bow cleat to bottom is 30 feet, the rode should be about 180 feet. In rougher conditions, the rode needs to be longer, and in calm conditions, the rode can be shorter.
Bigger is Better
People assume that because anchors are heavy, they work by using their weight to keep a boat in place. However, anchors work by using resistance instead.
When an anchor is dragged along the bottom, its shape and design cause it to dig into the bottom, encountering resistance. The weight of the anchor helps it dig in and prevent the anchor from moving. However, the majority of the force keeping the anchor in place is the resistance between the anchor and whatever it’s dug into (sand, mud, etc.).
Rope or Chain Anchor Rode
The two most common types of anchor rode are nylon line and metal chain.
Each have their pros and cons, with nylon anchor rope providing stretch and give that enables the rode to react to sudden movement. However, chain provides additional weight that helps the anchor dig into the bottom and lowers the angle of pull on the rode, reducing the pull on the anchor. Both line and chain have their advantages, so the best anchor rode is a combination of the two.
For short-term anchoring in calm, shallow waters, use about 8 feet of chain in the rode. As for longer-term anchoring such as overnight mooring, use a chain that’s at least 50% of the length of the boat.