A new trend in wave gear is reduced diameter masts, or RDMs, also known as skinnies. These masts are smaller in diameter and have thicker walls. Their largest single advantage is their resistance. RDMs last!

Conventional wisdom says that these masts are not as responsive as normal diameter masts: thinner mast walls in a larger diameter are thought to be faster in reflex return. This seems to have been proven true for racing and the large sail sizes associated with Formula.

Presently RDMs are exclusively wave masts and manufactured in shorter lengths; 370cm, 400, 430, 460, and 490cm. RDM masts normally include the necessary shim to make your boom compatible.

My experience is that RDMs are a definite plus. The reduction of mast diameter results in added sail shape at the sail front edge. RDMs give the rig a softer feel, slightly more power and a larger trim range. Compared to normal masts, RDMs may require more tension to set the outhaul due to the mast's reduced diameter.

My experience with RDMs is that the use range of the rig is effectively expanded as the rig becomes slightly soft and elastic. Softer feel, expanded range, and reliability are strong positive arguments for RDMs.

For more info on RDMs check The Loft Masts.