Anchor Scope Calculator

REF: EN-603-SCOPE

Calculate the exact amount of anchor rode (chain and/or rope) you need to deploy for a safe and secure anchorage. This tool uses the standard "Scope" ratio method based on water depth and your boat's bow height.

Vertical Drop: 0 FT

Why Use an Anchor Scope Calculator?

Proper anchor scope is the #1 rule of safe anchoring. The "scope" is the ratio of how much rode (chain and rope) you let out compared to the distance from your bow to the sea floor. If your scope is too short, the upward pull from your boat will break the anchor out of the mud/sand. If it's too long, you risk swinging into other boats or shallow water.

How the Math Works:

• Vertical Drop: You must add the Water Depth and your Bow Height together. If you are in 20ft of water, and your bow roller is 5ft above the water, your vertical drop is 25ft.
• Scope Ratio: You multiply the Vertical Drop by your desired Scope. For a 5:1 scope in our 25ft drop example, you need 125ft of rode.
• Tidal Fluctuations: Always calculate using the expected high tide depth. If you anchor at low tide in 10ft of water, but the tide will rise by 10ft, you must calculate for 20ft!