Hand lamination — repairing a hull puncture
Repairing a hull puncture with glass-epoxy laminate — a bevelled grind, laying the cloth and rebuilding the gelcoat.
A hole in the hull is structural damage that must not be repaired cosmetically — the laminate has to be rebuilt so that it carries the loads like the original. First assess the extent of the damage from both sides of the skin, because the delamination usually reaches further than the visible hole. Damaged, delaminated material has to be removed back to sound, well-bonded laminate. Only on a clean, strong edge can a new structure be built.
The key to the strength is the scarf around the hole — the edges are ground back at a shallow angle, creating a wide flange over which the successive layers of cloth gradually overlap the sound laminate. A ratio of the order of 1:12 is used (about 12 units of scarf length for every unit of thickness), which gives a large bonding area. The shallower the scarf, the smoother the transfer of forces and the lower the risk of cracking at the joint. After grinding, the surface has to be dusted off and degreased to give the resin good adhesion.
For a structural repair, epoxy resin is preferred, having better secondary adhesion and strength than polyester, together with glass cloths matched to the original. They are laid smallest to largest, usually starting at the bottom of the hole with small pieces and finishing with large ones that run well out onto the scarf. With access from one side only, a temporary backing of film on a rigid board is used, pressed from inside to recreate the shape of the skin. The number and weight of the layers should match the thickness and strength of the original laminate.
Laminating is done wet: the cloth is wetted out with resin and de-aired with a roller (a de-airing roller is best) and a brush, removing bubbles and excess resin. You work within the resin's window, laying successive layers wet on wet or after preparing the surface between cycles. Watch out for dry spots and unwanted air pockets, which weaken the laminate. The proportions of resin and hardener are measured exactly by weight or with a dispenser, because an error makes full curing impossible.
Once cured, the laminate is sanded flush with the skin and any hollows filled with epoxy filler. Then the outer layer is rebuilt: on a gelcoat hull, repair gelcoat is applied with the colour matched; on a painted one, primer and paint. From inside, reinforcing layers are added if necessary. Finally, on the underwater part, the barrier coat and antifouling are restored.
The whole operation needs stable conditions: a temperature within the range recommended for the resin, and a dry, clean working area. Working with epoxy calls for care — nitrile gloves, eye protection and respiratory protection when sanding, and good ventilation, because epoxy hardeners are sensitising and can cause a permanent skin allergy. Dust from cured laminate is an irritant, so a P3 mask and extraction are compulsory. Dispose of leftover resin as the regulations require.
If the hole is in a critical place (at a bulkhead, a stringer, near a seacock) or the core of a sandwich structure is damaged, the scope of the repair grows and it is worth consulting a specialist. In sandwich construction, the core (foam or balsa) and both laminate skins have to be rebuilt separately, taking care over how they bond together. A well-executed laminate repair is as strong as the original, and often stronger. Do not cut corners on the scarf or the number of layers — they are what decides the safety.
Material prices — products and options
Indicative prices in EUR (incl. VAT), as of July 2026. Products widely available in Europe; prices depend on the shop, the pack size and consumption. The links lead to example shops that ship across the EU. Dollar amounts are converted at 1 EUR = 1.1622 USD (ECB, 7 September 2026) and rounded — treat them as a rough guide, not a price in a US shop. Imperial values in brackets are conversions of the metric figure.
Epoxy resin with hardener
- WEST System — 105 + 205 Fast (0.6 kg (1.3 lb))
resin + fast hardener set, for small repairs€35–45 (≈$41–52) - WEST System — 105 + 205 Fast (1.2 kg (2.6 lb))
set for a medium repair, the standard for structural laminating€65–75 (≈$76–87) - WEST System — 105 + 206 Slow (6 kg (13.2 lb))
large set, slow hardener (longer working time, higher temperatures)€230–260 (≈$267–302) - R&G — Epoxydharz L + Härter
budget laminating system, resin + hardener — set of about 1 kg (2.2 lb)€20–30 (≈$23–35) - Sicomin — SR 1710 / SD system
premium marine laminating system (yachts, high strength)€40–70 (≈$46–81) / kg
Glass cloths (200–600 g (21 oz)/m²)
- SEATEC — glass cloth 200 g (7 oz)/m²
light finishing cloth / thin layers — price per m²€10–14 (≈$12–16) / m² - SEATEC — glass mat 300 g (11 oz)/m²
CSM mat for hand laminating (polyester) — price per m²€7–11 (≈$8–13) / m² - Glass mat 450 g (16 oz)/m² (by the metre)
heavier mat for building up layers — price per m²€9–15 (≈$10–17) / m² - R&G — biaxial cloth 600 g (21 oz)/m²
heavy structural reinforcement (biaxial) — price per m²€12–20 (≈$14–23) / m²
Fillers for epoxy filler paste
- WEST System — 407 Low-Density (150 g (5 oz))
light filler for an easily sanded fairing compound€24–29 (≈$28–34) - WEST System — 403 Microfibres (150 g (5 oz))
fibres for structural filler and bonding€16–20 (≈$19–23) - WEST System — 406 Colloidal Silica
thickening silica (controls slumping, fills gaps)€16–22 (≈$19–26) - R&G — microballoons / thixotropic agent
budget fillers (glass bubbles, Aerosil) — pack€8–18 (≈$9–21)
Sander and abrasive paper 40–80
- Abrasive paper 40–80 (sheets/discs)
for the scarf and for removing gelcoat — set€8–20 (≈$9–23) - Mirka — DEROS / Deos sander
random orbital with dust extraction (premium, for laminate)€350–550 (≈$407–639) - Orbital sander (budget)
cheap sander for home repairs€30–70 (≈$35–81)
De-airing roller, brushes, pots, scales
- Ribbed (de-airing) roller
metal roller for removing air from the laminate€15–80 (≈$17–93) - WEST System — 175 mm (6.89 in) resin roller
PU foam roller for applying resin€5–9 (≈$6–10) - WEST System — Mini Pump Set (dispensers)
pumps dispensing resin/hardener in a fixed ratio€25–35 (≈$29–41) - R&G — brushes, pots, digital scales
accessories: disposable brushes, graduated cups, 0.1 g scales€5–25 (≈$6–29)
Release film and a rigid board (backing)
- Easy Composites — Peel Ply
improves the surface and the bond of subsequent layers — roll€10–30 (≈$12–35) - R&G — release film (perforated/plain)
PA/PE or Mylar film for pressing down and smoothing — sheet/roll€6–20 (≈$7–23) - HDPE sheet / plywood for backing
rigid backing behind the hole (forming the patch)€5–20 (≈$6–23)
Gelcoat / primer and paint for the outer layer
- YACHTCARE — Gelcoat VT Repair Kit
gelcoat kit with hardener, film and paper — 180 g (6 oz)€30–40 (≈$35–46) - YACHTICON — Gelcoat Repair Filler (white)
ready-mixed paste for fine scratches and small gelcoat chips€10–14 (≈$12–16) - EPIFANES — 2K polyurethane paint (750 g (26 oz))
gloss, rebuilding the outer coating above the waterline€50–70 (≈$58–81) - International — Perfection 2K PU (premium)
very durable PU paint + primer, premium-class finish€130–170 (≈$151–198) - Undercoat primer (above the waterline)
epoxy/PU primer under the topcoat€25–60 (≈$29–70)
Personal protective equipment
- 3M — safety glasses
eye protection when sanding and working with resin€10–15 (≈$12–17) - 3M — FFP3 (P3) mask/half mask
respiratory protection against dust and fumes — per piece/pack€3–40 (≈$3–46) - Nitrile gloves (pack of 100)
disposable, resistant to resins and solvents€8–18 (≈$9–21) - Disposable protective coverall
protects clothes and skin when laminating and sanding€5–15 (≈$6–17)
Price sources: svb24.com, compass24.com, westsystem.com, r-g.de