Certain types of anchors work better than others. Since there are a half-dozen basic types, it is unrealistic to carry them all onboard. So any reasonable boater selects a couple of styles that seem proper for the general type of anchoring and bottom types expected. Depending on the size and type of boat, the next decision is the size and amount of chain; this too depends a lot on where you’ll be anchoring (and the weight capacity of the boat).
In theory we did everything right: checked three different weather forecasts (all of which were wrong, including two VHF Coast Guard marine forecasts!), used a 6:1 anchor scope, even dove on the anchor to check that it was in a good spot.
The anchor, deeply embedded in the mud because we had backed down on it, had pried up a huge ball of mud and clay when the wind switched direction and we swung around 180 degrees. This prevented it from resetting itself as we dragged towards shore.
Also, Scott failed to tell me that although the anchor seemed to be set in the mud, there was a thick covering of eelgrass and kelp around it. I avoid anchoring in such areas for both ecological and safety reasons (they do not provide good holding) and if I had known this I would have moved the boat. But Scott, unfamiliar with the San Juan Islands, didn’t realize this.
I also now remember to use an anchor alarm religiously.
We were very unlucky with the incident and very lucky with the outcome.