Category Archives: About Sunny Spells

Descriptive posts about Sunny Spells, her equipment, history and performance.

Freedom from the “Tyrrany of the Tiller”

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I have an ST4000+ wheelpilot on my 33ft Dick Carter sail boat. IMHO it is an essential piece of safety equipment when you are sailing shorthanded, or even just with a smaller crew (i.e. less than 4 people).

I recently had a challenging night offshore after splitting the mainsail in a squall (just after putting the 3rd reef in). Even though I had two crew, they were both too sea-sick to be of much use, and the autopilot steered perfectly under motor while I lashed the main to the boom and set the storm tri-sail.

The benefits in freeing you from the “Tyrrany of the Tiller” is obvious.

It is vitally important though that you:

  • fit a rudder angle sensor, otherwise the Autohelm performance will be mediocre at best, but probably next to useless;

  • select the location for the fluxgate compass very carefully to avoid magnetic and RF interference.

  • Getting it as close as posible to the keel will also minimise unecessary movement of the fluxgate, making the Autohelm more stable;

  • make sure all wiring is done professionally, cable joins are avoided as far as possible and cables are routed in dry areas (keep them out of the bilge if possible).

The Autohelm on Sunny Spells was pretty useless when I bought her, but after fixing the problems listed above, she now helms perfectly downwind for hours on end. I’ve had an 11 hour run downwind with poled out genoa and main by the lee without touching the autopilot controls (on wind-vane mode) other than accepting wind shift alarms.

The best $1000 you can spend!

Navbus/NMEA and Displaying Wind Data

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Mystery solved…

After a lot of correspondence, telephone calls and hours in the boat, in front of the laptop, decoding NMEA0183 sentences (did I really need to know all this stuff??), the mystery is finally solved…

It appears that the chartplotter firmware is the culprit. If Navbus is enabled on the chartplotter, it will only accept wind data from Navbus, not the NMEA0183 input. Disable Navbus, and the wind data is displayed!

It seems like a quick fix, but it comes at a price. The biggest issue is that DSC capability (i.e. automatic communication with the VHF to receive and transmit DSC messages) is lost. Also, the barometric pressure and air temperature data sensed by the VHF is now not available at the helm… Navman’s John Dusting said that he would request a firmware update to solve this issue, but it could be a while…

Preventer for the Main

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Yesterday I rigged a preventer to use when running downwind. It consist of about 30 meters of 8mm polyester braid line(stretchy) that runs all the way to the stem (outside everything), through a snatchblock and back to a jammer on the cabin top.

I can control the preventer from the cockpit and put it on a winch to set and (most importantly) ease off gradually when necessary. Sunny Spells has the main sheet attached to the end of the boom, and the preventer is attached at the same point, using a snap-shackle. This prevents bending moments being applied to the boom by the preventer and main sheet working in opposite direction, resulting in a broken boom… Fortunately this arrangement is also good at preserving the boom intact should it get dragged in the water!

At 25 meters, the preventer is long, almost double the required length. I did this on purpose so that I can just throw off the jammer when changing tack without worrying that the line will pull through the clutch. I just leave it shackled to the boom and re-run it after the gybe. Also, the snap-shackle stops the line from pulling through the snatch-block on the bow. When I need to re-set (or stow) the preventer, I just pull it through in the cockpit, flaking it on the cockipt floor, until the snap-shackle stops in the snatch-block on the bow. Now I go forward, swap the snatchblock to the opposite toe-rail, take the snap-shackle (outside the lifelines) and walk back to the cockpit, pulling it through as I go. I just snap-shackle it to the boom end, close the jammer and pull it tight – too easy.