Thursday, July 26

Anchoring Procedures

Anchoring is a simple procedure that can cause those new to the process great anxiety. If you follow the procedure step-by-step, you will give yourself the best chance for success. Even experienced anchor-ers, flub it up…the trick is to know sooner, rather than later, when it is going to go wrong, so that you can start over at the beginning.

Step 1: Scope
First determine the depth of the water in which you will be anchoring. You need this information so that you can calculate the proper scope (Figure 1). Scope is the ratio between the depth of the water, plus the height of the anchor chock above the water. I would recommend at least a 7:1 ratio. So if the water is 8 feet deep and your anchor chock is two feet above the water for a total of 10 feet, you would want to let out 70 feet of anchor rode to have the 7:1 ratio. I like the 7:1 ratio since it will give you room for error in the amount of anchor rode you let out and will make up for waves and other variables.

Figure 1. Thanks to Ohio Dept of Natural Resources

Step 2: Room to Swing
At a 7:1 ratio in 20 feet of water you will let out 140 feet of anchor rode. It is critical that where you choose to drop the anchor you have enough room to drift back. It is also likely that the anchor will drag a little before setting so having 150 feet behind the boat in this scenario is not out of the question. Of course, you can set an anchor on a shorter scope if the conditions are calm and there will always be someone on deck to watch for dragging.
Also, be aware that as the wind shifts the boat will swing around. Be sure that there is swing room. In the above situation, you would ideally have a circle around the anchor that is 300 ft in diameter. Of course, this rarely happens so be aware of the boats that are potentially going to be a problem (not everyone follows the rules!) if your boat swings one way or the other. Always be ready to haul up your anchor and reset in a more favorable location.

Step 3: Anchor Retrieval
Once it is time to go, hauling up the anchor can be a real chore without a windlass. To make it easier, motor the boat slowly in the direction of the anchor rode as someone on the bow hauls in the rode while pointing the helmsperson in the correct direction. If the anchor is set hard and will not release from the bottom easily, cleat off the rode when it is vertical with as much tension as you can get by hand. Then, let the motion of the boat work the anchor free. In extreme cases, you can motor the boat past the anchor location with the anchor cleated off, but be careful with this method since the boat is powerful enough to bend or break the anchor if it is stuck on a hard object.
If you get to a point where you cannot get the anchor free no matter what you try, tie a fender to the anchor rode and throw the whole thing overboard. Note your GPS position. Once you get home, you can call a diver to retrieve the anchor and with the GPS position and the fender floating the diver should not have any problem finding the anchor and freeing it from the obstruction.

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