420 The Lenam 420 racing dinghy

The 420 has strict rules on the materials that can be used to build it. Only polyester resin is allowed, and sandwich construction, which is permitted in classes such as the Optimist, Europe or Snipe, is banned. Starting from these premises, the raw materials used to build the Lenam 420 are of the very highest quality. The NPG isophthalic gelcoat and the isophthalic polyester resin, both with the highest HDT (the temperature at which gelcoat and resin can start to degrade), give the laminates unrivalled elongation and elasticity, so they withstand the toughest sailing conditions and suffer less than other boats in collisions.

The glass fibre used is powder-bound mat, which prevents osmosis problems and offers better chemical resistance than other, cheaper fibres.

These materials are much more expensive than the other permitted options, but they guarantee an unbeatable finish and a boat that lasts longer and stays competitive for longer.

As mentioned above, sandwich construction with PVC foam to stiffen the hull or deck is not allowed in the 420. What is allowed, to give the hull and deck strength, are omega-section reinforcements placed at the builder’s discretion. And this is where the Lenam 420 has a number of original reinforcement systems that perfectly combine minimum weight with maximum stiffness. In addition, because of its distinctive shape with a full bow, any 420 needs special care to keep that area light. Lenam achieves this with a particular design of very light, strong omega reinforcements in the bow, which also give the hull a centre of gravity further aft than its competitors, a key factor in short, steep seas or with heavier crews.

Once the hull and deck have been laminated, they stay in the mould for at least one week, post-curing at a constant temperature, to reach the degree of stiffness and cure that will give the finished boat a long life at full performance.

While the materials are very restricted, as explained above for the 420 rules, the class hull lines allow tolerances that leave plenty of room for manoeuvre. The Lenam 420 adapts very well to all wind and wave conditions. The short, steep chop so typical of the Mediterranean is very different from the long Atlantic swell: sailing off Arrecife is not the same as sailing on the Catalan coast, to give just one example. Drawing on the knowledge of racing sailors and instructors, the Lenam’s hull lines make it very easy to sail and give maximum speed in all these different conditions.

The position and depth of the centreboard and rudder have also been studied to optimise performance.

The deck design, the only one-piece deck among all 420 builders, helps to align perfectly the key elements in this area, such as the forestay chainplate, mast gate, mast step, centreboard case and rudder fittings.