Crew!

We went down to the boat this morning and I fitted my contraption.  It worked!  Friends then came and joined us for a little cruise around and some lunch. 

CyclopsJnr provided very competent crewing, helping align the steering for my contraption, dealing with shore power, opening and closing seacocks, letting go the bow rope, and stowing all the fenders when we departed.  He also did very well at person-overboard drills, which all the kids seem to love (who doesn't enjoy throwing something off a moving boat then trying to pick it up again???).

The contraption failed about half way through the cruise.  

A brief look after lunch showed I had underestimated how much the steering bar (which links the two outdrives) moves fore and aft as well as side to side, resulting in one of the linkages sheering off.  I then built version two (see extra) was then built and installed, with some nuts locked leaving the link bar with lots of fore/aft play in it, and a longer total length for reach at the steering extremes.  Testing appeared to show none of the bending and flexing that had previously caused a failure.  We'll see how we fare with this version next time we're out. 

For the curious, the blue assembly mounted on the transom (in the extra pic) is basically a potentiometer or pot (variable resistor, like a volume control) with a rotating shaft.  Turning the shaft varies the current through the pot (and voltage aross it) which in turn moves the indicators needles at the helm positions from side to side.  The bar in the bottom of the picture is the steering linkage between the two outdrives.  My meccano mechanism links the pot to the steering bar in such a way that the linear motion of the steering bar is converted to rotation of the pot.  The original mechanism seems to have involved a plastic arm which snapped off - probably years or decades ago. 

So now when the steering bar moves, the indicators at the helm show which way the steering is set.  This is pretty handy, as boats don't respond to the steering as quickly as cars (especially at low speed). Manoeuvring in confined spaces can get a bit tricky if you lose track of where the steering is, so can't be sure which way you'll turn if you blip the throttle!