NAUI Master Scuba Diver 268 Boating, Diving, and Seamanship Properly “dropping the hook” is done by slowly lowering the anchor until it has reached the bottom and letting out sufficient anchor line to achieve the proper scope, which is the ratio between depth and the amount of line deployed. Slowly pull on the anchor after it seems set by backing the engine to assure this. The three main reasons that anchors do not hold are: 1. Dropped incorrectly, causing anchor, chain, and the line to tangle or “foul.” 2. Not enough scope. It is recommended to have a minimum scope (length of line) seven times the depth of the water for ideal conditions, and a minimum of seven to nine times the depth for rough weather. The anchor and chain should lie on the bottom and pull parallel to the bottom. 3. Using the wrong anchor. For the majority of recreational boats used for diving, the lightweight Danforth anchor is the most widely used and the most effective (figure 12-10). HOW TO ANCHOR A DIVE BOAT The best way to anchor a boat for diving is to tie off to a mooring buoy, which preserves the environment and saves time and energy. Unfortunately, mooring buoys are not always available. • Slow down before you reach the dive site. If there are other boats in the area, they may have divers already in the water. Secondly, if near shore, shore divers may not have a float and flag. • Look for bubbles before “dropping the hook” to insure it doesn’t land on and injure a diver. If let out slowly, this is less likely to occur. • Try to anchor in the sand whenever possible. Every time coral is touched by an anchor, hands, or fins, it is damaged. Preservation and conservation are important. It is highly recommended to have an anchor line buoy or float. In the event a diver gets down-current and is in need of assistance, you will be able to tie off the anchor line to the float. This is faster, leaves a reference FIG 12-10. TYPES OF ANCHORS AND THEIR PARTS
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