Buying a used catamaran: the specific points to check

A used cruising catamaran is judged like any other boat — papers, history, hull, engine, rigging — and the general checklist applies in full. But a multihull has its own points: a structure that works differently, two engines and often two saildrives, heavily loaded rigging with no backstay, and a large share of the market coming out of charter. This guide covers only what changes.

1. The structure: what joins the two hulls

On a monohull, the hull is a single piece; on a catamaran, two hulls, a bridgedeck and a forward beam are assembled, and it is these joints that take the loads. That is where you look first.

• Hull-to-bridgedeck and hull-to-deck joints, inside and out: gelcoat cracks that follow the joint (a single fine crack is cosmetic; a network of parallel cracks, or cracks that come back after repair, is not), signs of touched-up paint.
• Forward beam and dolphin striker (the wire or bar under the beam): play, corrosion at the fittings, cracks at the attachment points on the hulls, condition of the forestay chainplates.
• Underside of the bridgedeck: marks from wave slamming (the bridgedeck “slams” in a seaway), delamination (a dull sound when tapped), water ingress where cables pass through.
• Internal structural bulkheads: the fillet between bulkhead and hull coming away, doors that no longer close, floorboards that buckle — signs of a structure that has moved.
• Mast step and its supporting bulkhead or beam: compression, cracks, damp in the surrounding sandwich.
• Bows: impacts from anchoring or berthing, repairs; the fine bows of recent catamarans are fragile.

Tapping with a nylon hammer and a moisture meter, with the hulls out of the water, are more useful here than on a monohull: the sandwich (balsa or foam) is everywhere, and water ingress spreads unseen.

2. Two engines, two saildrives, two of everything

Everything in the guide to inboard engine maintenance counts double, and there must be a history for each engine, with its own hours.

• Hours and logbook for each of the two engines; a big difference between them (one engine used a lot on its own, the other little) calls for an explanation.
• Saildrives: replacement date of the diaphragm seals (interval set by the manufacturer, often seven years), saildrive anodes, oil not milky, no corrosion of the aluminium leg (copper antifouling applied by mistake, galvanic currents in the marina).
• Engine compartments at the bottom of the hulls: ventilation, traces of seawater, condition of the through-hulls and hose clips.
• Cold start of both engines, manoeuvring in the marina on both engines (this is what makes a catamaran easy to handle, provided both respond), how each comes up to temperature.

3. The rigging

A catamaran does not heel: the load goes into the rigging and the structure instead of being absorbed by heeling. The shrouds, chainplates and mast work harder than on a monohull of the same size, and there is generally no backstay.

• Standing rigging: replacement date (replacement recommended at around ten years, earlier with intensive use or in the tropics), broken strands at the swages, corrosion on the turnbuckles, condition of the chainplates and how they are tied into the structure.
• Square-top mainsail and its battens, mast cars, rigid vang; furlers for the genoa and any additional headsail.
• Boom and gooseneck, which are heavily loaded on a catamaran; reinforcements and cracks.
• Electric winches (often fitted on larger models): operation, wiring, servicing.

4. Rudders, steering, appendages

• Two rudders, two bearings: play, alignment of the two rudders with each other, no water inside the rudder (out of the water: weeping, weight).
• Steering link between the two rudders (tie bar, cables or rams): play, corrosion, fixings.
• Daggerboards or keels: play, noise, condition of the daggerboard case; on daggerboard models, the lifting mechanisms.

5. Ex-charter boats

A large share of used catamarans from 38 to 46 feet come from charter fleets, generally sold on after five or six seasons. In itself, that is neither good nor bad news: these boats have sailed a lot, often with inexperienced crews, but they have also been maintained by charter bases on a regular schedule, and they are sold after a refit (“phase-out”). What matters is the file.

• The base’s maintenance programme: engine services, haul-outs, rigging replacements, with dates and hours.
• The phase-out report: what was refitted before the sale, and what was not.
• The equipment: charter boats are equipped for charter (watermaker, generator, sometimes air conditioning), not always for independent cruising (electronics, power, anchoring); what is missing has a cost.
• Signs of intensive use: upholstery, floorboards, headlinings, knocks on the bows and sugar scoops, tired portlights and sliding door.
• Title and VAT: a boat that has sailed under a foreign flag or outside the European Union may have a VAT status to check before buying — proof that VAT has been paid is one of the papers to ask for.

6. What costs more than you think

• Lifting and handling: few boatyards have a trailer or crane suited to a catamaran’s beam; hauling out has to be planned and is priced accordingly. Find out what is possible near your home port before you buy.
• The berth: a catamaran takes two berths or one wide berth, with a surcharge in most marinas, and a longer waiting list.
• Maintenance: two engines, two hulls, twice as many anodes and through-hulls. The guide to maintenance costs gives the ranges specific to catamarans.

7. On the sea trial

• Under sail, close-hauled: pointing angle, behaviour in gusts, bridgedeck slamming in a chop.
• Under power: speed and cruising revs on both engines, then on one; vibration; marina manoeuvres.
• Inside the boat, at sea: doors and drawers that bang or stick (a structure that is working), creaking bulkheads, leaking portlights.
• After the trial: bilges on both sides, engine compartments, no new water.

8. The questions to ask the seller

• Has the boat been in charter? With which base, for how many seasons, with what fleet exit report?
• When were the saildrive diaphragm seals replaced, on each leg? The standing rigging?
• Have there been any structural repairs (bridgedeck, forward beam, bulkheads)? By whom, with what photos?
• Where and how is the boat hauled out, and when was each hull last antifouled?
• What is the VAT status, and under which flag has the boat sailed?

A seller who keeps a Hullteam log answers all of that with a link: the sale file shows each engine with its hours, each job with its proof, and the documents they have chosen. For a given model — the Lagoon, Fountaine Pajot, Bali, Nautitech, Outremer and Catana boats common on the used market — the model page lists the known points to watch with their source, the maintenance schedule and the cost range. And for a catamaran more than ten years old or an ex-charter boat, an out-of-the-water survey, with tapping and a moisture meter, is almost always a good investment.