Effective anchoring depends on boat size, wind and weather, and what the bottom is made of — there's no magic formula, but this chart is where Greenfield starts every sizing conversation. Find your anchor family, read across to your boat length, and check the scope and chain columns before you buy.
The short answer: Match anchor weight to boat length: a 10 lb mushroom suits a 12 ft small craft, the slip-ring fluke holds boats to 22 ft, the 18 lb Richter to 22 ft, and the 25 lb Richter to 26 ft. Wind, current, and bottom type matter as much as length — when in doubt, size up.
The chart, row by row
Every number below is transcribed from the printed chart — anchor weight on the left of each arrow, the boat length it's rated for on the right.
| Anchor | Duty | Weight → boat length | Scope | Chain |
|---|---|---|---|---|
| Mushroom | Light duty, soft conditions | 8 lb → 10 ft · 10 lb → 12 ft · 15 lb → 16 ft | 5:1 | Optional (1/4 in × 4 ft coated) |
| River | Medium duty, soft to moderate conditions, structure | 14 lb → 16 ft · 16 lb → 18 ft · 20 lb → 22 ft · 30 lb → 24 ft | 5:1 | Optional (1/4 in × 4 ft coated) |
| Richter | High performance, most conditions, easy retrieval | 18 lb → 22 ft · 25 lb → 26 ft | 4:1 | Optional (1/4 in × 4 ft coated) |
| Navy | Light/medium duty, soft to moderate conditions | 10 lb → 14 ft · 15 lb → 18 ft · 20 lb → 24 ft · 27 lb → 28 ft | 7:1 | Recommended (1/4 in × 4 ft coated) |
| Slip-Ring Fluke | Light/medium duty, most conditions, easy retrieval | Model #6 → 18 ft · Model #11 → 22 ft | 7:1 | Recommended (1/4 in × 4 ft coated) |
| AYS Fluke | Medium/heavy duty, most conditions | 8 lb → 24 ft · 13 lb → 28 ft · 17 lb → 32 ft | 7:1 | Recommended (1/4 in × 4 ft; the 17 lb uses 5/16 in × 5 ft) |
One footnote on the fluke row: the printed chart rates the #6 slip-ring for 18 ft, but the small fluke kit is sold for boats up to 16 feet — shop by the kit's number.
Where each row leads
Every row Greenfield sells today has a guide and a product page. Here's the map:
- Mushroom (10 lb → 12 ft): light duty for jon boats, dinghies, and PWC, and the classic second anchor for the stern. Read the mushroom anchor guide or go straight to the 10 lb Mushroom Anchor.
- River (20 lb → 22 ft): medium duty for current, structure, and pontoons. The river anchor guide covers it; shop the River Anchor or the River Anchor Kit.
- Richter (18 lb → 22 ft, 25 lb → 26 ft): high performance in rocks, mud, weeds, and sand, at the least scope in the lineup. Start with the Richter anchor guide, then the Original Richter Anchor or the Richter Anchor Kit.
- Slip-ring fluke (model #11 → 22 ft): the sand-and-mud specialist with slip-ring retrieval. The fluke anchor guide explains the dig-in; shop the Slip-Ring Fluke Anchor or the Complete Fluke Anchor Kit (small kit to 16 ft, large to 22 ft).
- Navy and AYS fluke: rows from Greenfield's wider printed line-up, not sold on this site. In the store lineup, the slip-ring fluke covers light/medium fluke duty and the Richter covers the heavy end, up to 26 ft.
What do the scope and chain columns mean?
Scope is how much line you let out relative to depth, measured from your bow cleat to the bottom — 7:1 means 7 feet of line for every foot of depth plus bow height. The differences between rows are real feet of rope: in 8 feet of water with a 2-foot bow, a 7:1 fluke wants about 70 feet out, a 5:1 river or mushroom about 50, and a 4:1 Richter about 40. That spread is the chart's honest version of the Richter's needs-less-line reputation.
The chain column marks coated chain recommended for the fluke-style rows because their holding is all dig-in — chain keeps the pull flat so the flukes bury — and optional for the cast families, whose weight already keeps the pull low. The physics gets its own anchor chain guide, and the full drop-set-verify technique is in how to anchor a boat.
Between rows, or past the chart?
Size up. Wind, current, and bottom type load an anchor as much as boat length does, so when your boat lands between rows — or your weather does — take the heavier anchor.
Three lookups come up constantly. A 22-ft boat has three chart answers — the slip-ring fluke, the 20 lb river, and the 18 lb Richter — and the tie-breaker is bottom type: sand and mud take the fluke, current and structure take the river, mixed or rocky takes the Richter. A 24-ft boat is past the 22-ft rows; the answer is the 25 lb Richter kit, rated to 26 feet and the largest rating in the current line. And the 15 lb river anchor sold on the site sits between the chart's 14 lb and 16 lb rows — call it gear for the 17–22 ft pontoon-and-fishing class, with the 20 lb river kit covering the top of that range.
Deciding between anchor families rather than weights is a different question — start with how to choose a boat anchor, or get the whole rig matched in one box via the anchor kit guide.
Complete Fluke Anchor Kit
Sand-and-mud holding for boats to 22 ft — anchor, chain, line, and shackles matched.
See the kit
Richter Anchor Kit
The 26-ft ceiling of the line: 4:1 scope holding in rocks, mud, weeds, and sand.
See the kit
Mushroom Anchor, 10 lb
Small-craft duty for jon boats, dinghies, and PWC — and the classic stern anchor.
See the anchor
Common questions
What size anchor do I need for my boat?
Match weight to boat length on the chart: a 10 lb mushroom for a 12 ft small craft, a slip-ring fluke or 18 lb Richter for boats to 22 ft, a 20 lb river anchor for boats to 22 ft, and the 25 lb Richter for boats to 26 ft. Then size up if you anchor in wind, current, or on unfamiliar bottoms — conditions load an anchor as much as length does.
What anchor do I need for a 24 ft boat?
The 25 lb Richter anchor kit. It's rated for boats up to 26 feet — the largest rating in Greenfield's current line — and it holds at 4:1 scope in rocks, mud, weeds, and sand. Nothing else in the store lineup carries a rating past 22 feet.
What does the scope column on the chart mean?
It's how much line to let out per foot of depth, measured from your bow cleat to the bottom. Fluke-style anchors plan on 7:1, river and mushroom anchors 5:1, and the Richter 4:1. In 8 feet of water with a 2-foot bow height, that works out to roughly 70, 50, and 40 feet of line respectively.
What does chain 'recommended' vs 'optional' mean on the chart?
The chart recommends a 4-foot length of 1/4-inch coated chain for fluke-style anchors because their holding is all dig-in — chain keeps the pull flat so the flukes bury. For mushroom, river, and Richter anchors the same chain is optional: their cast weight already keeps the pull angle low. Greenfield's anchor kits include coated chain either way.