Ten pounds of cast iron with manners. The mushroom is the smallest, simplest anchor Greenfield makes, and it's honest about its job: it holds small craft in calm water over soft bottoms, and it pulls second-anchor duty on bigger boats. Everything past that line belongs to a bigger anchor — and knowing where the line sits is the whole trick of buying one.
The short answer: A 10 lb mushroom anchor holds kayaks, canoes, jon boats, dinghies, and PWC in calm water over soft bottoms, or as a second or stern anchor on bigger boats. It grips by settling in — suction, not digging — so its ceiling is light duty. Pontoons, current, or rock call for a river anchor or Richter.
What is a mushroom anchor used for?
Four jobs: holding small craft in calm water, riding as a second or stern anchor on a bigger boat, slowing a drift while you fish, and weighting buoys or markers. The 10 lb model is sized for the small-craft class — kayaks, canoes, PWC, jon boats, dinghies — where our selection chart puts it at boats up to about 12 ft.
It's also the anchor that's easiest to live with. Ten pounds stows in a kayak well or a transom locker, and the coating keeps bare cast iron off your hull and deck. It comes in Black, Royal Blue, Red, and White, and it's made and coated in the USA — the same early-1960s Ohio shape Greenfield introduced and the rest of the industry copied.
How does a mushroom anchor hold?
By nesting in, not by hooking. The rounded cap settles into soft mud, silt, or sand, and in a genuinely soft bottom it builds real grip — the BoatUS Foundation notes the mushroom shape "can create a suction that can be difficult to break." That's the whole mechanism: the softer the bottom, the better it holds.
What it doesn't do is dig. There are no flukes to bury and no tines to grab, so the grip resists steady, light loads and gives up under hard, gusty ones. True mooring mushrooms hold big boats by weighing hundreds or thousands of pounds; your 10-pounder is the portable cousin, and it plays by lighter rules.
Will it hold a pontoon or a 20-footer?
Not as the primary anchor, no. A pontoon catches wind like a sail, a 20-footer in current pulls harder than suction in mud can answer, and a rocky bottom gives the cap nothing to settle into at all. We won't pretend a 10 lb mushroom is a storm anchor — it isn't, and anyone who tells you otherwise is selling you a return.
If the boat is a pontoon, runs in current or wind, or is bigger than the small-craft class, the mushroom is the wrong primary anchor — it will drag, and more line won't change what 10 lb of suction can resist. Step up to the river anchor for pontoons and current, or the Richter for bottoms that change trip to trip.
How much line does it need?
Plan 5:1 for a short stay — 5 ft of line for every foot from your tie-off point down to the bottom. In 8 ft of water that's roughly 40 to 50 ft of line, depending on how high your bow or deck sits above the surface. Chain is optional on a mushroom; the cast weight already keeps the pull low.
Using it takes about fifteen honest seconds:
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Lower it to the bottom
Soft mud, silt, or sand — the softer the bottom, the better the suction.
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Pay out 5:1 line
Enough scope keeps the pull sliding along the bottom instead of lifting the cap.
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Give it a moment to settle
It holds by nesting in, not by hooking — the grip improves as it seats.
The rest of the craft — proving a set, landmark checks, retrieval — is in our guide on how to anchor a boat.
Why is it the classic second anchor?
Because the second anchor's job is small, and 10 lb does it perfectly. With a bow anchor set and holding, a stern anchor only has to stop the swing — that's why bow-and-stern is the convention at crowded sandbars, where every boat holding still means more boats fit. A mushroom drops off the transom in seconds, stows anywhere, and never asks to be the main event. One rule rides along: the stern anchor works in addition to the bow anchor, never instead of it — the bow always does the holding.
The same logic makes it a drag anchor for fishing in current: lowered on a short line, it slows your drift so you can work a stretch of water instead of blowing past it.
When your boat outgrows it
The day you buy a pontoon, step up to a 17-footer, or start anchoring where the water moves, move up the line — that's not a failure of the mushroom, it's the design working as labeled. The 15 lb river anchor covers the roughly 17–22 ft class with cast weight plus tri-fluke engagement, and the Richter handles rocks, mud, weeds, and sand on 4:1 scope. Match weight to boat length in the anchor size chart before you spend a dime.
If the small job is yours, this is the cheapest good decision on the site. If you're not sure which job you have, start with how to choose a boat anchor and let the water you boat on make the call.
Common questions
Will it hold my pontoon?
No — not as your primary anchor. A 10 lb mushroom resists steady, light loads by settling into soft bottoms; a pontoon catches wind like a sail and will out-pull it. Use a river anchor for pontoons and current, or the Richter for bottoms that change trip to trip. As a stern-swing stopper behind a properly set bow anchor, the mushroom is fine.
Is it good for a kayak or PWC?
Yes — that's exactly its class. Kayaks, canoes, PWC, jon boats, and dinghies are what a 10 lb mushroom is sized for; it stows easily and the coating won't chew up a hull. Lower it to a soft bottom, give it 5:1 line, and let it settle for a moment before you trust it.
Is it made in the USA?
Yes — made and coated in the USA. The mushroom is one of the original Greenfield shapes introduced in Ohio in the early 1960s, and every one is still coated at the family-owned shop in Greenfield, Ohio. It comes in Black, Royal Blue, Red, and White.
Can I use it as a stern anchor?
Yes — that's the classic second job for a 10 lb mushroom. Set your bow anchor first and let it do the holding; the stern mushroom just stops the swing, which is why bow-and-stern is the convention at crowded sandbars. The bow anchor always does the work — a stern anchor rides in addition to it, never instead of it.
Do I need chain with a mushroom anchor?
It's optional. Our selection chart lists chain as optional for mushroom anchors because the cast weight already keeps the pull low; a short length of coated chain flattens the pull further if you keep one boat rigged full-time. For a kayak or dinghy, line alone is normal.