“What boat do I need?” is the first question everyone asks about crossing an ocean — and of the five questions that decide whether your crossing goes well, it is honestly the least important. The ocean is crossed every year by tired old sloops and gleaming new catamarans, by 27-footers and 60-footers. What their successful crews share is not a hull. It is preparation. Here is the boat question answered the way we would answer it over a beer in the cockpit of Cloud Nine.
What “bluewater” actually means
A bluewater boat is one that can take more punishment than its crew. Strip away the forum wars and the label comes down to a short list: stability that recovers (a design that comes back up from a deep knockdown — ask for the stability curve, not the brochure), a cockpit that drains and a companionway that seals (most water that gets below walks in through the front door), a rudder you can trust (skeg-hung or robustly engineered spade — rudder loss is the classic mid-ocean disaster), and tankage and stowage for three-plus weeks of water, food, and spares without burying the waterline. Everything else — bowsprits, brands, full keels versus fin — is preference dressed up as doctrine.
Size: the honest answer
Oceans have been crossed in boats you can almost carry. The practical question is not “can it make it” but “can you live it”: for a cruising couple, 35–45 feet is the enduring sweet spot — big enough for tankage, spares, and an easy motion in a seaway, small enough that one scared, tired person can reef it alone at 3 a.m. That last clause is the real size limit. If the boat overwhelms your weakest watchkeeper on the worst night, it is too much boat, whatever the ocean thinks.
Monohull or catamaran
Both cross oceans in numbers every season; neither is the wrong answer. The monohull is self-righting, cheaper per foot, and forgiving of the overloading every cruiser commits — the price is heel, motion, and a smaller platform. The catamaran gives speed, space, and a galley you can cook in mid-passage — the price is purchase cost, marina math, and a discipline the monohull enforces for you: a cat does not warn you by heeling, so you reef by the numbers, early, every time. Pick with your budget and your crew’s comfort, not with the internet’s.
The proven boat beats the perfect boat
The lists of “proper bluewater boats” are long, contradictory, and mostly a way to postpone leaving. Meanwhile the anchorages of the Marquesas fill every year with ordinary production boats — sailed there by crews who spent their money on rigging and their winters on preparation. A surveyed, sound, boring boat you can afford to refit beats the legendary design that consumes your whole budget at purchase. Condition beats pedigree. The refit beats them both.
The refit matters more than the purchase
Whatever you buy, the work that makes it an ocean-crossing boat happens after the survey: standing rigging under ten years old (insurers and riggers agree on little else), every through-hull and hose clamp inspected and double-clamped, self-steering that can drive the boat for two weeks straight (a windvane or a properly sized autopilot with spares — hand-steering an ocean is a myth that lasts one watch), a power budget that survives cloudy days, and safety equipment beyond the legal minimum. Then the paperwork stack: a real passage plan and a float plan left with someone ashore who knows what to do with it.
The boat carries you. Something still has to carry the news. Whatever hull you choose, the family ashore lives the same two weeks of silence. That is the problem WatchKeeper was built for: the logbook you keep anyway becomes a twice-daily plain-language shore brief, delivered over the Iridium or Starlink you are already installing in the refit.
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Ocean-crossing boat FAQ
What is the best boat to cross an ocean?
The one that is strong, simple, well-maintained — and paid for, so the refit budget exists. Oceans are crossed every year by 40-year-old production boats and brand-new catamarans alike. Design matters (a skeg-hung or well-engineered rudder, a proper companionway, real tankage), but the condition of this particular boat matters far more than the reputation of its class.
What size boat do you need to cross an ocean?
Boats under 30 feet cross oceans every season, and the record-setters are far smaller. For a cruising couple, 35–45 feet is the sweet spot: big enough to carry water, food, and spares with an easy motion, small enough that one tired person can reef it at 3 a.m. Displacement and design matter more than length — a heavy 32-footer can be a better sea boat than a light 45.
Can a small boat cross the Atlantic?
Yes — routinely. The trade-wind route has been sailed by boats under 20 feet, and every ARC fleet includes boats around 30 feet. Small means slower (plan 25+ days rather than 18) and wetter, with harder provisioning math, but a well-prepared small boat is safer than a poorly prepared big one. Preparation, not length, is the safety variable.
Is a monohull or a catamaran better for ocean crossing?
Both cross oceans safely in numbers every year. Monohulls are self-righting, cheaper per foot, and more forgiving of overloading; you pay in heel and motion. Catamarans give you speed, space, and a flat platform the crew loves; you pay purchase price, marina fees, and the discipline of reefing early — a cat does not warn you by heeling. Choose by budget and crew, not internet wars.
How much does an ocean-crossing boat cost?
A capable used bluewater monohull in the 35–40 ft range runs roughly $40,000–$150,000 USD, with proven older designs at the low end. Then budget 20–50% of the purchase price for the refit that actually gets it ocean-ready: rigging, sails, autopilot or windvane, safety equipment, power. The cheapest hull is rarely the cheapest boat.