Dinghy Catamarans – Just how fast are they ?

By William Sunnucks, Tornado GBR 405

Anyone who sails a dinghy catamaran, from a Dart 15 through to a Tornado, will tell you that his (or her) boat is fast.  But catamaran superiority doesn’t register with the wider sailing community, whose bar bragging rights seem to continue unabated.

The annual Hoya Round the Island Race provides a good opportunity to compare.  Over 1500 big boats compete, their times are rigorously measured and published on the race website.  Every type of yacht is competing on the same day in the same conditions. 

The Island Sailing Club doesn’t allow dinghies to enter, but there is no rule stopping you “observing” the race from your boat, and so long as you are scrupulous about keeping clear there can be no complaint.  Normally there are a few small boats – 18ft skiffs or Hurricanes out for the spectacle and to compare their speed.  I have now been round five times with the big boats, and the statistics on speed have become interesting.

It is clear that a Tornado 2001 is faster than all the monohulls, and all the multis except for some “Grand Prix” entries.  This year Maiden II was entered – previously Club Med, now bought by Tracy Edwards to break records.  She didn’t break the RTI record this year because the wind was in the wrong direction.  But the huge Ocean going racing machine finished nearly 1 ½ hours ahead of the next boat, only 13 minutes outside the record.

The 2002 results above, which cover only the leading boats from the faster classes, are fairly typical – one or two ‘Grand prix’ multihulls beat the Tornado, the rest trailing behind mostly out of sight.  This year Provu might have beaten us but for a messy spinnaker drop at Bembridge and a poor last beat up the Solent.  The huge trimaran, Rexona Men, would also have been ahead;  after storming off the start line on port tack with two hulls flying she ground to a halt on the Lymington shore while trying to tack

But what does this mean for other small catamarans ?  I have linked the ISAF handicaps with those used by the Hoya organisers, using one key assumption:  I have assumed that Carbon Tiger and the Tornado 2001 are sailed to the same standard.  The Carbon Tiger crew includes Rob Gutteridge who sailed dinghy catamarans with me for many years, and ex Hurricane sailors such us Brian Haynes and Keith Bliss.  They are consistently strong performers in F27 events, and make a good benchmark.

Once this assumption is made a number of interesting comparisons follow: 

The bars show the linked SCHRS handicaps.  For example Maiden II would have an SCHRS handicap of .72 calculated from the Tornado SCHRS (.95) x Tornado TCF (1.545) divided by Maiden’s TCF (2.026).  The Tornado’s TCF comes from the average actual result against Carbon Tiger from the last two Hoya races.

The diamonds show the actual elapsed time in the 2002 Hoya Round the Island Race for comparison.  They give you an idea of the quality of the linked handicaps as a predictor of performance.  Note that:

• Maiden II did well compared to its linked handicap, as did Gleam, Bear of Britain and Carbon Tiger
• A well sailed Hurricane 5.9 (secondhand cost £3500) should be able to beat all monohulls with aplomb -  and most of the multis
• A Dart 18 should be ahead of all but the fastest monohulls

What then are the weaknesses of this analysis. 

• Firstly I have used two windy days for the comparison.  Although I have sailed round in previous years I haven’t kept the times.  But from memory the dinghy catamarans do better against large multihulls in the lighter winds due to their higher sail area to weight ratio, but worse against the monos.  It will be interesting to measure this properly in future years.
• Secondly wave conditions make a huge difference.  It was noticeable that the bigger boats were faster in the big waves to the south of the island. The Tornado was slowed by waves hitting the beam.  I am convinced that a dinghy catamaran will do best with a Northerly force 5 – 6.  Although it will be gusty and difficult to sail, the water will be flatter and the speeds much higher.

Although index linking ratings for such different boats is potentially dodgy, I do believe that this exercise combined with the Hoya results provides small cat sailors with some fact based counter bragging rights.