Set a Sailboat Anchor
After cruising a 38' sloop in Mexico for three years it became obvious that proper anchoring technique is not widely understood. Here is a method that will insure a tight set and prevent dragging of the anchor.
- NOTE: These instructions are intended for those using an all chain rode. (see "tips" below)
- Pick the spot to drop your anchor by circling round the area watching the bottom contours on your depth sounder and looking for rocks or obstructions in what will be the swing radius of your anchor rode. Remember, you may well swing a full 360 degrees over time.
- Return to your intended drop spot, motoring very slowly, directly up wind.
- Using reverse, stop all motion of the boat. At the moment the boat stops, drop the anchor straight to the bottom as quickly as possible. Do not allow excess anchor chain to fall on top of anchor as this is likely to cause fouling.
- If there is a breeze the bow will begin to swing off in a line, roughly downwind. DO NOT USE THE ENGINE to back down because this will cause the chain to be laid down in an arc rather than a straight line. Instead allow the wind to drive the head straight downwind as you pay out chain. Do not release chain too fast to avoid creating piles. (If there is no breeze, see step 11, below, then return to step 6.)
- When the appropriate scope has been released (approximately a 5 to 1 ratio, scope to depth) snub off the chain and let the boat settle back, bow to wind and anchor location. This may take a few minutes in a light breeze.
- Put the engine in reverse at idle and allow any slack to be pulled out of the chain. (You should be able to feel this happening with a foot or hand on the chain in front of your windlass.)
- Very gradually increase the engine speed in reverse to pull tension on the chain. Start at about 1000 RPM. You will see the chain pull taut and then the weight of the chain will pull the boat back forward a bit. When this happens, increase the RPM by 500 RPM increments until you reach 2000 RPM.
- During this process, observe two fixed reference points ashore, perpendicular to the boat and watch for any drag. If there is no movement at full power for one minute and you can feel no little jerks in the chain you are well set. Shut down power and go fix a margarita.
- If there is any drag at all go back to neutral, let the boat rest a moment and return to step 6 and try again. If this attempt is unsuccessful you must either try to find a better holding spot or start over. Chances are that either the anchor is located in poor ground or perhaps the anchor is fouled in some way.
- If there is not sufficient breeze in the anchorage to cause the boat to swing off fast enough to allow paying out chain evenly, you must use the engine in reverse to back down. Do this at no more than idle speed. If you back down under more power the anchor is much less likely to take a good set and you will wind up just plowing a furrow in the bottom. This is the biggest mistake made in most people's anchoring technique.
- An all chain rode is the only viable option for real security in a cruising environment. The extra weight is only a nominal factor for a fully rigged cruising boat and is mandatory for sleeping well when the wind is gusting to 30 knots at 3:00am.