Crossing a Channel in a Catamaran: Notes from 30+ Knots

A lot of catamaran sailing advice is written by people who have never been upside down, and a lot of monohull advice assumes a keel that a catamaran doesn’t have. This is the middle way: what we actually do aboard when a crossing is going to be a fight, distilled from the Mediterranean, the Atlantic crossing, and every squall that tried to teach us otherwise.

The boat is a vehicle, not a boat

Monohulls forgive with weight; catamarans forgive with trim and shape. Three things follow:

Stow everything that isn’t bolted down. In 30 knots the dinghy is a missile, the fenders are shrapnel, and a loose mop handle is a sabre.
Rig for the worst quarter you expect, then add 10% more. If you expect 25, rig for 30. The reef is the fastest “engine” a catamaran has.
Heel is data, not a target. Below 15 degrees the appendages are happy. Beyond 25 the leeward hull starts to wash out and the boat gets ugly fast.

The rig, in order

Sails	At 15 kt	At 25 kt	At 35 kt
Mainsail	Full	1 reef	2 reefs
Genoa	Full, 1 wrap	1–2 wraps, shortened	Furled
Wind	Moderate	Gusting	Squally
Attitude	Motoring optional	Motoring on	Motoring off, cover on

The table is opinion with evidence: it’s what kept our average speed honest and our crew calm through the Balearic Channel and both Atlantic legs. The attitude row matters as much as the canvas — a catamaran crew that is scared is a catamaran crew that is slow, and slow boats make bad decisions.

Watch routine in a blow

Helm: 2 hours on, 4 off. The autopilot takes the helm; the human takes the sea state. Autopilots sleep at the first real squall line.
Galley: dry food only, cold drinks only. Hot food in a blow is a surrender.
Below: the companionway is a ramp, not a door. Every watch hand practices the roll-down from bed to deck while the boat is still kind.

Representative passage — mid-Atlantic, February

From	Las Palmas, Gran Canaria
To	Tenerife (Santa Cruz)
Distance	84 nm
Duration	2 days
Avg speed	5.8 kn
Notes	30–38 kt northwest, seas 4–5 m. Two reefs, motoring 6 h. The rig above, verbatim.

What I would do differently

More canvas up before the front, not after. Every time we’ve reefed under pressure instead of ahead of it, the boat has cost us an hour and a bruise. The forecast is wrong, the sky is only less wrong — plan for the sky, not the app, and reef early enough that the crew can still be smiling about it.

Svastrum under two reefs in the mid-Atlantic, sails pressed flat, wind racing off the leeward hull — Two reefs, 35 knots, and the crew still took a photo. (The camera survived. Barely.)

Full rigging diagrams and the reefing log for the Atlantic crossing are in the next technical article — it’s the one you actually want.