The ground tackle I'm specifying for our 50-foot family cat — anchor, chain, windlass, and where I'd overspend

I have $13,800 budgeted for ground tackle on a boat I haven't bought yet. A 50-foot cruising catamaran, four kids, a five-year route that will park us in a Caribbean squall, a Pacific atoll lagoon, and probably some Mediterranean blow we didn't plan for. The boat is hypothetical. The anchor we will hang off the bow is not. That number — call it $14K all-in for anchor, chain, snubber, secondary, windlass upgrades, and spares — feels like a lot until you price out the alternative, which is dragging at 0300 onto somebody else's transom.

So here's what I've been working through over the last few months: the actual ground tackle spec for our cat. Real product names, real weights, real prices. I'm writing this partly to think out loud and partly because every "best anchor" thread I read online turns into a tribal fight before anyone shows their math. I'd rather show mine.

The boat assumption

Spec I'm planning around: a 50-foot performance-cruising catamaran with daggerboards, displacement around 17,500 lb light and maybe 22,000 lb fully loaded for a family Atlantic crossing. Bridgedeck height around 30 inches. The candidates I keep circling are an Outremer 51, a used Catana 53, and as a sanity check on price, a Fountaine Pajot Saba 50. Different boats, similar windage, similar ground tackle problem.

That windage is what matters for the anchor spec. A 50-foot cat presents roughly twice the side area of a monohull of the same length once you count both hulls, the bridgedeck, and the rig. When you read a windlass manufacturer's sizing chart that says "30 to 52 feet," you should mentally subtract about 10 feet if you're on a cat. They are sized for monohulls. So am I.

The primary anchor

The four anchors in my final pile: Mantus M1, Mantus M2, Rocna, Spade A180. I ruled out the Ultra fairly early — it tests well, but at roughly $2,400 for the 88-lb size it's twice the price of a Mantus that holds about the same, and I cannot justify that to a budget that has four kids' worth of foul-weather gear on the same page.

The argument between Mantus and Rocna is mostly a religious one at this point. Both are new-generation scoop anchors. Both set fast in sand and clay. Both have years of cruiser testing on every ocean. The differences I actually care about:

The Mantus M1 has a roll bar. The M2 doesn't. The roll bar helps the anchor right itself in really soft silty mud, which is exactly what you find in places like the Chesapeake, the Rio Dulce, and big chunks of French Polynesia's high-island anchorages. The downside is that the bar adds bulk and can catch weed. The M2 trades the roll bar for a leaner profile that's easier to ship on a bow roller and less prone to bringing up a Caribbean grass salad.

The Rocna 88 — 88 lb, designed by Peter Smith, built in either New Zealand or Canada depending on the year — has a similar resetting story to the M1. There was a steel-grade scandal a decade back that made me nervous; current Rocnas are reportedly back to spec, but the brand still carries a tiny bit of asterisk in my head.

The Spade A180 takes a different approach. Instead of a roll bar, the Spade ballasts the tip with lead, which pulls the point down into the seabed and forces the right attack angle. That ballast is also why a Spade weighs about 88 lb and feels like 130. In side-by-side pull tests I've seen on hard sand, the Spade often outperforms the rollbar anchors by a meaningful margin. It is also the anchor that singlehanded circumnavigators seem to keep choosing, which is a soft data point but not nothing.

What I'd actually buy: the Mantus M1 at 105 lb. One size up from the "recommended" 85 lb for a 50-footer. Sizing up the primary is the cheapest insurance on the boat. The difference between an 85 and a 105 is about $300 and twenty pounds of steel; the difference at 0300 when the squall hits is whether you sleep through it.

Mantus M1 105 lb, galvanized: $1,649.

The chain

The chain question is two questions: grade and length.

Grade first. G4 (sometimes called High Test or HT) versus G7 (also called G70 or Acco Pewag). G7 is stronger by roughly a factor of two at the same diameter. That means you can drop from 10mm G4 to 8mm G7 and get the same working load with half the weight per foot, which on 300 feet of chain is about 250 lb you don't have to carry in the bow.

I am going to spend the money on G4 anyway. Here's why. Galvanized G4 chain is universal. Every chandlery on every coast sells it. If we're in the Marquesas and need to extend our rode after a calibration issue at the windlass, I want to be able to walk into a place and find what I need. G7 is not universal. The weight penalty of 10mm G4 is also working in my favor at anchor — it adds catenary, which softens snubber loads in a chop. I'll accept the bow trim hit.

Length. We're planning 300 feet (about 90 meters) of 10mm G4 as primary, with the last 50 feet painted with calibration marks every 25 feet. That gets us 10:1 scope in 30 feet of water, which covers most anchorages on the planet, and 7:1 scope in 43 feet, which is fine for an overnight in moderate conditions. For the deep stuff — Med moorings, Tongan bays, the occasional 60-foot anchorage — we'll splice on 200 feet of 5/8-inch nylon three-strand. That gives us 500 total feet of usable rode and a stretch-y section for any time we're at full chain anyway.

Acco G4 10mm chain, 300 feet, galvanized: $2,250. Nylon tail with thimble: $310.

The snubber and bridle

This is the part most monohull sailors get wrong on cats. You cannot snub a catamaran the way you snub a monohull. The chain comes off a central anchor locker between the bows; if you run a single snubber line from the chain to one bow cleat, the boat will sail back and forth across the wind, putting cyclical loads on the rode that will eventually break something.

What you want is a bridle. Two legs of nylon — I'm planning 18mm Mantus Bridle — clipped onto the chain with a Mantus chain hook (or a stainless Wichard hook, same idea), then led back through chocks to a cleat on each bow. Equal length to start, then adjusted so the boat sits centered on the wind. The bridle does three jobs: it spreads the load between two structurally strong points, it eliminates the side-to-side hunting, and it adds about 12 feet of nylon stretch that absorbs every gust.

The piece I would not skimp on is the hook. A failed snubber hook in 25 knots is a recoverable event. A failed snubber hook in 45 knots when you're trying to sleep is a transom-into-coral event. Mantus stainless chain hook for 3/8-inch chain: $99. The bridle itself, 25 feet per leg, two legs, 18mm braided nylon with eye splices: about $480.

I'll also carry a 30-foot backup snubber in 16mm braid for storm conditions. That one lives in the anchor locker, not the cockpit, because by the time you need it you don't want to be opening lazarettes in the dark.

The windlass

If we end up on an Outremer 51 or a Catana 53, the boat likely comes with a windlass. I've been looking at Lewmar V8 and Maxwell HRC10-10 as the two I'd accept; both are properly rated for 10mm chain and a fully loaded 50-foot cat. Both manufacturers publish the same rough rule: the windlass should be sized so its working pulling power is at least three to four times the total ground tackle weight you're lifting. With 105 lb of anchor, 300 feet of 10mm chain at about 1.6 lb per foot (480 lb), and the snubber gear, you're looking at roughly 600 lb of total tackle. Multiply by four and the windlass needs to pull 2,400 lb. The HRC10-10 is rated for 3,300 lb of working load and 1,500 lb of normal pull, which means under heaviest expected load you'd be at the windlass's design ceiling, not above it.

What I'm planning to do regardless of which boat we buy: rewire the windlass directly to a dedicated 12V bank in the bow, not the house bank back at the helm station. Voltage drop on long DC runs is real, and a windlass at 11.2V works dramatically worse than one at 13.6V. A 200 amp-hour AGM in the forward locker, fused appropriately, paid back the first time we have to drop the hook in 40 feet of water at the end of a long passage when the kids are losing their minds and the dog has had it.

The secondary anchor

You don't need a fancy secondary. You need an anchor that's a different shape than your primary, because the failure modes of a Mantus and the failure modes of a Fortress are completely different, and if one drags, you don't want to swap to another anchor with the same failure mode.

My plan: Fortress FX-37 (21 lb) on 50 feet of 3/8-inch chain with 200 feet of 5/8-inch nylon rode, stowed disassembled in a cockpit locker. Total weight to lug around: less than 30 lb. It's the storm anchor, the kedge for getting off a soft grounding, the second hook for a Bahamian moor in a tide-reversal anchorage. The Fortress is aluminum, holds extraordinarily well in mud and sand, and packs flat. It's the second-most-important anchor on the boat, and it costs $640.

For the actual storm anchor — Galerider or Jordan Series Drogue territory, the thing you stream off the stern in survival conditions — that's a different post and a different problem. The Fortress is the second anchor, not the storm gear.

The tally

Primary anchor (Mantus M1 105 lb): $1,649. Primary chain (300 ft Acco G4 10mm): $2,250. Nylon tail (200 ft 5/8" three-strand): $310. Bridle hardware (Mantus 18mm bridle + hook + spare snubber): $679. Secondary anchor + rode (Fortress FX-37 kit): $640. Dedicated windlass battery and rewire (parts, assumed labor at a yard): $1,800. Chain marking paint, swivel, shackles, and spares: $300. Bow roller and chain stripper upgrades (assuming the boat needs them): $1,200. Sail to the chandlery a second time because you forgot something: $300. Round up for shipping and the inevitable upcharge in St. Thomas: $500.

Total: just over $9,600 for the gear I'd buy fresh on a boat that has a competent windlass already. If the boat needs a new windlass too — call it a Maxwell HRC10-10 installed at about $4,200 — you're at the $13,800 I budgeted.

What I'd skip if I had to cut

Honestly, not much. The thing I would not cut is the primary anchor weight — I'd rather buy a used boat with a flaking interior than an undersized hook on a clean one. Same with the chain length; coming up short on rode is the kind of mistake you only make once.

What I would consider trimming if I were a different person on a tighter budget: the secondary anchor goes to a Fortress FX-23 instead of the FX-37, the bridle goes from 18mm to 16mm nylon, and the dedicated windlass battery becomes a heavier-gauge DC run from the existing house bank. That probably saves $1,500 and degrades the system in ways I'd notice once a year, on the worst night.

I'm not that person. The single biggest variable in whether a five-year family circumnavigation is fun versus terrifying is whether the boat stays put when we tell it to. Everything else — the watermaker, the Starlink, the iridium, the lithium house bank, the carbon mast — those make the trip nicer. Ground tackle is what makes the trip possible.

If you're interested in how we're thinking through the boat itself, we've been working off a 47-point catamaran selection worksheet that breaks the buying decision into the variables that actually matter. It's the framework that's gotten me from "I want a cat" to "Outremer 51, here's the budget."

Next week I'll walk through the dedicated bow-locker battery wiring in more detail — fuses, wire gauge, the math behind a 200 amp-hour AGM versus a 100 amp-hour LiFePO4 in that location, and why I keep leaning AGM despite being a lithium evangelist everywhere else on the boat. That one's actually a closer call than the anchor was.