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third rail, two


third rail, two

Sailing Anarchy readers will remember our attempts to keep the massive power of the I550 under control by fitting Three rudders. I thought you might like an update. While the Three rudder system worked well in winds around 35 knots, there were Three serious performance issues:

  1. An excess of drag at low wind speeds made the boat less than competitive.
  2. The Three rudder arrangement dramatically increased the JIP numbers (Jellyfish impact probability). As anyone who sails on Port Phillip knows, frequently hitting one of the millions of big blue jellyfish that infest the place in summer, is a major speed reducer.
  3. A precious part of my anatomy got tangled in the complex rudder linkage every time I tried to relieve myself.

We therefore tried the single rudder configuration, which worked well right up to wind speeds of around 30 knots….for a while. It destroyed itself last Wednesday at a boat speed of about Fourteen knots while we were manoeuvring for the start of the RYCV afternoon pursuit race.

We put the cause down to harmonic vibration, in aviation circles called "flutter". You can hear the rudder humming merely to itself on this YouTube video from the "Snoo Cam" we placed on the stern.

Said rudder is currently being rebuilt from Unobtainium.

Regards,
Walrus