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A steam launch carries its history in its hull. Before you think about varnish, brass or a rebuilt boiler, the timber under your feet decides whether the project is a season's work or a five-year obsession. Whether your launch is a 24-foot carvel-planked gent's launch or a small river boat with an elm garboard and a tired sternpost, the approach is the same: assess honestly, repair traditionally, and protect properly.

Survey the Hull Before the First Hammer Blow

Start by emptying the boat. Remove ballast, floorboards, the boiler and engine beds if you can, and get the hull under cover with good through ventilation. Damp, still air is the enemy of every wooden hull.

Buy a decent moisture meter and take readings along the planking, from sheer strake to garboard, at several points along the length. Remember that a hull kept afloat will always read wetter than one kept ashore, so compare like with like. A launch that has dried out for months will show tight seams and open caulking, which tells you very little about how it behaves in the water.

Tap the planking gently with a small caulking mallet. Sound timber rings; decayed timber gives a dull thud. Then use a bradawl, not a screwdriver, to probe suspect areas. It should enter sound oak with resistance and come out dry. If it slides in like butter and weeps brown water, you have found rot.

Reading the Timber: Where Decay Hides

Identify your planking species before buying anything. Traditional launches used oak, larch, pitch pine, teak or mahogany, and each weathers and swells differently. Oak is strong but reacts with iron fastenings; teak is durable but oily and resists glue.

Decay follows water, so look in the places water sits and lingers:

• Hood ends at the stem and transom, where plank ends dry and open.
• The garboard strake and the keel rabbet, forever damp from bilge water.
• Beneath a leaking deck, where fresh water drips onto frames for years.
• Around the sternpost, rudder trunk and shaft log, often the worst area on a steam launch.
• Engine beds and boiler bearers, where heat and condensation combine cruelly.

Small localised problems can be dealt with by splining or letting in a graving piece. Larger areas need a new plank, scarfed to the old one at a ratio of at least eight to one and steamed if the curve is severe. Use oakum-free, well-bedded joints and always check the fastenings in that plank before you commit to the work.

Fastenings: The Hull's Hidden Skeleton

Planking is only as good as what holds it on. Copper roves clenched over nail points are the traditional standard for a launch of any age, and they last remarkably well. Bronze screws are excellent. Galvanised or wrought-iron fastenings are the worry, especially in oak, where they corrode and waste away invisibly.

Draw a few fastenings from each area: a plank here, a frame there. Drill out a sample rather than pulling them, examine the shank and head, and look for dezincification, cracking or a neck worn to half its diameter. A hull can look perfect and still be "nail sick", holding together by habit.

If you are refastening, work in silicon bronze or copper roves and keep metals compatible. Isolate dissimilar metals with bedding compound, and never mix stainless screws into oak that already carries copper — the corrosion you create will outlast your patience. While you are in there, check the keel bolts, stern gland, rudder bearings and engine bed bolts. These take the loads a steam plant imposes.

What Previous Repairs Are Really Telling You

Every old boat carries the fingerprints of earlier owners. Fibreglass sheathing over wet planking traps moisture and hides rot. Cement poured into the bilge is a classic bodge that holds water against the keel. Filler over a soft spot simply postpones the day.

Do not automatically condemn these repairs — some were sensible at the time — but do remove them and see what lies beneath. Photograph everything, keep a written log of what you find and what you decide, and record the reasoning. In three years you will be grateful. Understanding why a previous owner did something often tells you more about the hull than the damage itself.

Caulking, Paints and Traditional Protection

Caulking is a skill worth learning properly. Reef the old seam, drive cotton or oakum in with a caulking iron until it is firm but not brutal, then pay the seam with red lead putty or a traditional stopping compound. Over-caulking is the commonest mistake: it forces planks apart and creates leaks where none existed.

For protection, follow the old sequence. Prime bare timber with a red oxide or linseed-oil primer, follow with an undercoat and a good gloss above the waterline. Below the waterline, use a suitable anti-fouling over compatible primer. Penetrating epoxy systems can work well, but only on timber that is sound, dry and stable — never as a way of hiding a problem. Paint the bilge properly, leave the limber holes clear, and keep air moving through the boat at all times.

A Sensible Order of Work

Work from the structure outwards: strip and support the hull, survey thoroughly, repair keel and frames, replace or splice planking, refasten, caulk, then paint. Trying to paint before the structure is sound simply wastes expensive coatings.

Budget for the unglamorous items — fastenings, caulking cotton, bedding compound, primer — as these consume more of a restoration than most owners expect. When she goes back in the water, allow the planking to take up slowly, check the bilges daily, and keep a pump handy. A cared-for wooden hull, repaired honestly and protected with traditional paints, will give decades of quiet, steady steaming.