Hull Materials: GRP, Timber, Steel, Aluminium
Four answers to what a boat is made of — each material has its own problems, its own maintenance schedule and its own owner profile.
What a boat is made of is the DNA of its maintenance budget and survey approach. There are four main worlds, and each has its own problems, its own schedule and its own specialist. A ‘general look-over’ is not a proper survey on any material.
The table below sets out the four materials by maintenance, typical defects and the correct survey method.
Hull materials
Material | Maintenance | Typical defect | Survey method |
|---|---|---|---|
GRP / fibreglass | Easiest | Osmosis, UV fatigue | Moisture meter, hammer test |
Timber | Ongoing, requires craftsmanship | Rot, woodworm, caulking | Knife tip, nose, experience |
Steel | The paint system is everything | Rust (inside and out) | Ultrasonic plate thickness measurement |
Aluminium | Moderate | Galvanic sensitivity | Potential measurement, check for copper contact |
The used-boat market follows the same logic: GRP is the most liquid market; steel and aluminium need buyers and surveyors who know the material; timber is as much about whether there is a proper network of craftsmen as it is about price. On steel, do not be fooled by a shiny topside paint job — the critical issue is the full paint system (stripping, epoxy primer), not the final coat.
The buying compass is straightforward: for easy life with marina and bay cruising, choose GRP; for character and tradition, choose timber — but only with the right craft network behind it; for long-range cruising and impact resistance, choose steel or aluminium. Whatever the material, insist in the survey on the test method that belongs to that material.