Rode is everything between the boat and the anchor: chain plus rope. Here is how much to let out for your depth.
(Water depth + bow roller height) × scope = rode to let out
Example: 15 ft of water + 3 ft bow height = 18 ft. At 5:1, that's 18 × 5 = 90 ft of rode.
Scope is the ratio of rode to the vertical distance from your bow roller down to the bottom. Use water depth measured from the waterline to the bottom. Check whether your sounder displays depth below the transducer, below the keel or below the waterline, and correct it before adding bow height.
Use the greatest water depth expected during your stay, even if the tide is falling when you arrive. Also check clearance beneath the boat at low water.
Your depth, your boat
5:1 scope
7:1 scope
10:1 scope
Enter a depth. Results are rounded up to the next whole foot and count chain plus rope.
The chart
Between rows, round up to the next depth. Outside this range, use the formula or the calculator above.
Rode to let out with a bow roller 3 ft above the waterline
Water depth
Depth + 3 ft bowvertical distance
5:1 scope
7:1 scope
5 ft
8 ft
40 ft
56 ft
10 ft
13 ft
65 ft
91 ft
15 ft
18 ft
90 ft
126 ft
20 ft
23 ft
115 ft
161 ft
25 ft
28 ft
140 ft
196 ft
30 ft
33 ft
165 ft
231 ft
35 ft
38 ft
190 ft
266 ft
40 ft
43 ft
215 ft
301 ft
45 ft
48 ft
240 ft
336 ft
50 ft
53 ft
265 ft
371 ft
Measure your own bow height: each extra foot adds 5 ft of rode at 5:1 and 7 ft at 7:1.
Picking a scope
5:1 may suit short, attended anchoring in calm, sheltered conditions with suitable gear and good holding ground. BoatUS describes a shorter 5:1 scope as acceptable for a lightweight anchor on a small boat in good conditions.
7:1 is the general recommendation from BoatUS and Discover Boating for rope and chain rode, subject to your anchor manufacturer's instructions.
10:1 is what Better Boat's anchoring guide suggests for stormy conditions, which is 530 ft in 50 ft of water with a 3 ft bow. More scope may help when conditions worsen, but no ratio makes holding certain. Reassess shelter, bottom, gear and swing room. Relocate before conditions become unsafe.
Scope alone doesn't mean you'll hold.
Bottom type matters. A fluke anchor does well in sand or mud and poorly on rock, according to Discover Boating.
The anchor has to suit your boat's size, and it has to actually set. Let the wind or current carry you back (or back down slowly) as the rode pays out.
Secure the rode to a suitable bow strong point. Set and verify the anchor holds, then monitor position. Check the full swing area for boats, shoals and obstructions.
Weather changes. BoatUS advises letting out more rode as the wind builds.
More rode means a bigger circle around the anchor, so make sure you have the room for it.
Is your rode long enough?
On this chart, 100 ft of deployed rode covers the 15-ft row at 5:1 and the 10-ft row at 7:1. Count deployed chain plus rope. Allow for line needed aboard. Deeper water, or 7:1 in 15 ft or more, needs a longer rode; BoatUS recommends carrying extra line.
Optional product:Boat Anchor Lines: 100 ft of 3/8 inch double braided nylon with a pre spliced stainless thimble and a reflective strand, rated at an 820 lb working load. This is a line-load rating, not a boat-weight limit. Match rope diameter, chain, shackles and length to your boat and anchor.
Gear for this job
Complete setup
Boat Anchor Kit: a fluke style anchor with chain, shackles and rope, sized by boat length.
Rode and connections
Boat Anchor Chain: a short chain section (4 or 5 ft by size) with connection shackles. Length is a product size, not a chain recommendation for your boat.
Boat Anchor Swivel: a 316 stainless steel swivel that fits between anchor and chain.
