How much anchor line should you use if the water is 20 feet deep?

It depends on the boat and environmental conditions, a good rule of thumb is to use a scope a scope (amount of anchor line deployed) of at least 5:1. To estimate the amount of scope needed in feet add the depth of water to the rise from deck to water line multiply that by 5.

For example: if the water depth is 20’ and your rise from the deck to the waterline is 3’, your scope would be (20’ +3’) x 5 = 115’.