Blog · Guide · By Lenam Vela Ligera · Updated: September 2026

The 420: what to look for in a two-person racing dinghy

Rules, materials and construction of the most popular two-person dinghy, from the people who build it.

In short: The 420 rules only allow polyester resin and ban sandwich construction, so the difference between boats lies in the quality of the materials, the reinforcements and the build. Lenam has built it under licence since 1998, with isophthalic gelcoat and resin and powder-bound mat.

The 420 is the most popular two-person racing dinghy in the world, and in Spain the class is going through a great moment. At Lenam we have built it under licence since 1998, so we know what to look for when buying one.

Strict rules

The 420 has strict rules on materials: it only allows polyester resin and bans the PVC-foam sandwich construction used in other classes. What is allowed to stiffen the hull and deck are omega-type reinforcements, placed as each builder sees fit.

What makes a better 420?

• Materials: in the Lenam 420 we use NPG isophthalic gelcoat and isophthalic polyester resin, both with the highest HDT, which give an elasticity that withstands the toughest conditions and suffers less in collisions.
• Glass fibre: powder-bound mat, which prevents osmosis problems and resists chemicals better.
• Reinforcements: our own reinforcement system, combining minimum weight with maximum stiffness.
• Process: we build the 420 without rushing; every step has been studied in detail.

These materials cost more than other permitted ones, but they give a better finish, a longer life and a boat that stays competitive over the years.

420Two-person racing dinghyOptimistIODA rules · 35 kgILCA4.23 m · 58 kg

You may also like

GuideSailing dinghy: polyethylene or fibreglass?Construction, toughness, maintenance and which to choose, from people who work with both materials.Read the articleGuideILCA 4, ILCA 6 or ILCA 7: which one to chooseOne hull, three sails: who each one is for and how to move up from the Optimist.Read the article