Wednesday, 20 January 2016

Simon's Town - Autopilot Modifications

Hi everyone,
As mentioned in several posts previously (in particular here), we've had problems with our autopilot rams.  We have two complete Raymarine SPX5 systems with two Type 3 tiller rams. Two rams have lasted only 5000nm or so each.

The Raymarine man here in Simon's Town is very good and seems well connected with senior Raymarine staff in the US.  He looked at the system configuration - both software and hardware - and made several recommendations.  We have now completed implementing them all.

First we changed several configuration parameters, all of which are Dealer Calibration settings.  Our original calibration runs (separately for the two systems) resulted in Rudder Gain and Counter Rudder settings being set very high.

Rudder Gain reduced
Counter Rudder reduced
Rudder Damping unchanged
Secondly we had two s/s brackets manufactured.  These allow us to mount the ram on either port or starboard sides.  Keeping the ram on the windward side is recommended since it reduces arm extension which (we're told) should reduce wear-accelerating vibrations.  The mounts move the entire ram inboard which eliminates the 150mm arm extension we previously used.  This should further reduce vibration.

Thirdly we had a second pin fitted to the tiller, matching second mounting points on the two brackets.  These allow us to fit the rams 150mm further aft.  This gives us some redundancy (in case one of the pins detaches for example) and may perform better in some conditions.

Modified tiller with new brackets port & starboard
While here we've also discovered a company which manufactures "drop in replacement" rams.  Pelagic Autopilot appears to have a good reputation and I'm told their rams are longer-lasting.  We may well give them a try if the above changes don't stop our Raymarine rams wearing out prematurely.  Thanks to Jim of Canadian sv Haulback for the tip!

Other boat work done recently includes:
  • replacing two lost/damaged fenders
  • purchased iNavX Navionics charts for Caribbean and Europe
  • generated GoogleEarth imagery for Windward and Leeward Caribbean islands

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