Catamaran performance measures

HOW can the average sailor cut through the sales spin and assess the relative performance of so many different catamaran designs now on offer? In this article a set of just five numbers are proposed for assessing the relative performance of cruising sailing catamarans, obtained from six measurements usually published in marketing material.

It is intended that the Cruising Helmsman editor will use these metrics when conducting catamaran boat tests for the magazine.

The five performance numbers and its nomenclature are:

1. tippiness number (stability): tip
2. speed downwind in light winds: Vld
3. speed downwind in fresh winds: Vfd
4. speed upwind in light winds: Vlu
5. speed upwind in fresh winds: Vfu.

The six design characteristics usually found in sales brochures that will be used for the performance numbers are:

• weight
• sail area
• length overall
• beam overall
• hull draft
• if the boat has retractable boards, the area of a board.

There are some example results given