Knowing how to safely anchor your boat can make the difference between a peaceful uneventful evening and a costly disaster.
Having an anchor ready to drop if an emergency should arise is important and can save you a great deal of trouble and expense.
Even if you are not planning to anchor, having one all set up and ready to go is a major source of security on your boat.
Chosing the RIGHT Anchor
Before you go anchor shopping you have some homework to do.
- The kind of bottom you will typically anchor in. Different anchors are better holding in some materials than in others. Often charts will have this information. Ask the folks around you what they use.
- Decide what kind of anchoring you plan to do. For example do you just want to anchor and go swimming around your boat? Are you expecting to anchor in high current, or during bad weather? Is an anchor only as a safety feature of a daysailor? Within reason it is not a problem having a larger than required anchor, in fact if the conditions are likely to be difficult it is a very good thing.
- How are you planning to store your anchor and rode? (The line, chain and fittings) Some anchors are just plain nasty to handle and stuff in a locker. Are you planning to mount your anchor at the bow with rollers and a windlass?
- How deep is the bottom? This will determine how much line/chain you need.
Now you can start doing your research.
Choosing the right line/chain (rode)
Unlike old fashioned anchors which depended on sheer mass to anchor a boat, most modern anchors rely on their shape and how they are positioned on the bottom.
Once the anchor is dropped and is pulled along the bottom the anchor will gradually bury itself and this is what provides the hold.
In some types of bottom this is impossible such as in rock or coral, in that case the anchor hooks onto a rock or coral.
In order to position the anchor correctly and insure that the pull is horizontal along the bottom, the rode must be heavy enough. There are a great number of recommendation for the length and weight of the chain. Each anchor manufacturer will have specific suggestions as to what is best for their anchor.
Generally more is better than less. There are practical limitations as to how much chain a boat can carry but longer chains greatly enhance the effectiveness of an anchor.
Proper type and length of rope is also important. Typically nylon is used because it is elastic and resistant to breakdown by UV and chemicals. It is a mistake to use too large a line because this prevents the proper stretching and cushioning provided by the nylon rode. Snubbers are sometimes added to the rode if stretch is insufficient or if the boat will be subject to strong forces such as big waves or strong winds.
Manufacturers often recommend that a rode be from 7 to 10 times the water depth including the height of your boat. If there are tides then use the high tide depth. The more extreme the conditions the safer a longer rode is.
Anchoring.com has a good page on how to choose rode. Well worth having a look.
Setting the Anchor
You've found a good place to anchor, and checked that your boat can safely swing around. There is enough water even when the tide is low and you will not be swinging into someone else's boat
You've also checked that the tidal current is not extreme and that you are out of any traffic channel. You've tugged in any tender to keep it out of the way as you set your anchor.
You also know that your type of anchor will hold in this type of bottom.
The rest is quite simple. Come in slowly against the wind or current and drop your anchor slowly where you want it playing out line till it hits the bottom. Let the boat gently drift back as you play out more chain. Don't just drop the anchor and lots of chain because the chain will land on the anchor and might foul up the anchor and you will have to do it again. Some types of anchors are particularly bad about getting tangled up such as grapnel anchors.
Gradually play out line and when you have about half of your rode out, stop feeding it out and let the boat drift and pull the anchor. Hopefully it will start digging in and will slow or stop the boat. Wrapping the line a couple of turns around a cleat is helpful. When you feel this happening, let out more line till all your rode is out. At that point your anchor should have righted itself and lined up and dug itself in tight and solidly.
Watch for drift, If you are not solidly in then start again.
There are several ways of checking if you are drifting. Many GPS will have anchor watch features which will let you know if your get out of the expected circle swing. You can also check your GPS to see if you are moving downwind or down current. You can take a couple of compass bearings on nearby things if you can see the shore. These should stay constant if you are not too close to shore. If the angles change then check your anchor.
Anytime the pull on your anchor changes because you are swinging around with wind changes or tides, you should make sure your anchor is holding.
When you want to raise your anchor, gradually take in the rode. When you are on top of the anchor (some people put a float to indicate where the anchor is, others have markers on the chain so that they know how much chain remains underwater) gently pull the anchor and it will dislodge and come up. YOU HOPE.
If your anchor does not come up, going upwind and pulling sometimes helps to reverse the pull direction and hopefully free the anchor. Some anchors have special features such as attachments further forward on the anchor or have telescoping arms. These sometimes help.
Finally you want to have your anchoring light on. You can also fly a black ball if its daylight.On Board video about Anchoring the Boat Good video on Anchoring.
My web page on different types of anchors.
I try to be accurate and check my information, but mistakes happen.email me if you find mistakes, I'll fix them and we'll all benefit: Christine