one pound for each foot
Well, I meant boat length. For anchoring while fishing or lunch, the rule of thumb is one pound of anchor for each foot of boat length plus one foot of chain for each foot of boat length.
Types of anchors is another issue. Around here with mostly hard packed sand a Danforth type is fine, just wait awhile before you back down. For short stops, multiply the depth of the water + anchor roller height off the
water X4. If windy or big swells, X 5 to 7.
Always, if anchoring overnight, use at least seven times the depth.
Contact me for more opinions -

. I only spent 4 years anchoring as we roamed about in our 46'
Tom