Bartimaeus

Clare did most of the work at Bidford Grange Lock.  Once she was back aboard I started the diesel engine and set off, hoping that the clattering noise from the HybridMarine system wouldn't recur.  It didn't, but it was a measure of how used to it I had become that I was ready to respond under certain conditions.

It wasn't far to the bridge at Bidford-on-Avon, where I knew I had to choose an arch unexpectedly far over to the left.  The flow was very gentle, so there was no difficulty doing so.  The water was also very clear, so it was easy to see the obstructions under the water that we would meet if we picked the wrong arch.

The battery wasn't quite fully charged as we reached the mooring, so I carried on downstream, partly to continue charging and partly to explore the options for winding.  I winded in a wide straight section without getting as far as Marlcliff Corner - the guide suggests the section after the corner might be narrower with a shallow edge on one side.  As we returned to the mooring, the battery's state of charge jumped to 100% - perfect.  We've been doing short distances each day, so this was the first time in over a week we'd got the batteries properly full.

The following day we had arranged to meet up with Den and Andrea.  They are buying a second-hand Ortomarine boat, and want to upgrade it to a parallel hybrid.  Caroline at Ortomarine spotted an opportunity for all of us.  We want to upgrade Bartimaeus to serial hybrid, and so our parallel hybrid system will be coming out and available for re-use.

We were still chatting to our newly arrived guests on deck in the sunshine when my phone rang.  It was a call from HybridMarine - arranged by Ortomarine - to give advice about the clattering.  I was pleased to hear that there is indeed a correct tension for the belt, and even happier to be told that there was a phone app to help set it correctly.

I reported this to Den, but didn't think I would start experimenting in the engine bay with an audience.  After some more chat, we cast off and Den drove us on electric down the river to the place I'd turned the night before.  After he'd completed the turn we started the engine so that he could see the charging system in operation.  This was where I didn't want things misbehaving - and they didn't.

He took us through the bridge and turned again in another wide spot I'd noted the previous day before taking us back (on electric) through the bridge and on to our mooring again.  Den is an extremely competent helmsman, so the whole trip was very relaxing for me - and I had a willing audience for stories about the behaviour of the boat and its systems.  Clare and Andrea had retreated to the front cockpit for the duration of the cruise to talk about less technical matters.

Later that day I clambered in to the engine room again to investigate the belt tightening.  Previously I had only seen the User Manual, but I had now been sent a copy of the Maintenance Manual.  This includes instructions for using an adjustment screw to increase the tension in the belt.  To check the tension was correct, I loaded up the Gates Carbon Drive app on my phone (other apps are available) and then twanged the belt.  The app displays the frequency of the twang!  The correct frequency is 122Hz - a slightly flat bass B.  I got the tension right without much trouble, but I don't recommend the HybridMarine belt as a musical instrument.

I tested the behaviour of the drive while we were moored.  It isn't good practice to run the propellor while moored, but I didn't want to repeat the experience of discovering a problem after casting off.  I was pleased to find that it behaved flawlessly.