Weldon MarineBoating calculators
Notice to marinersPreview: the Helm Pass is $1.95 a month or $19.50 a year and is free during preview. Nothing is charged. Pricing

Calculator 3 of 4 · free

Anchor rode and swing circle

How much line to let out for the scope you want, and how wide a circle the boat can swing through once it is set.

Tip: a free Boat Card remembers your boat's numbers and fills these in.

Tide or lake level. The depth that counts is the deepest it will be.
The Coast Guard's general rule is 5 to 7 times. More in wind or a poor bottom.
Clear

Example: 8 feet of water, bow cleat 2 feet up, 7:1, a 20-foot boat.

Source: U.S. Coast Guard, A Boater's Guide to the Federal Requirements for Recreational Boats, "Anchoring" (PDF page 40): five to seven times as much line as the depth of the water plus the distance from the water to where the anchor attaches at the bow. The same page warns: do not anchor from the stern, as this could swamp the boat.

Before anchoring somewhere new, ask the local marina or harbormaster about the bottom, the room to swing and where anchoring is allowed. A boating safety course covers anchoring in full.

Helm Pass $1.95 a month or $19.50 a year · Free during preview · what it buys

With the Helm Pass, the Helm Card prints a rode table for your boat at 5 to 30 feet of water.