Windgenerator

As our style of cruising has slowed down we are no longer running the engine for long enough hours to keep the batteries properly topped up and it does not seem right to have to run the big diesel engine just for what amounts to a fraction of a kilowatt for the last few amps over a couple of hours that are necessary.  A petrol (or gas) generator would be noisy and besides I do not want petrol on the boat.  I explored the possibility of a methanol fuel cell, but these are obcenely expensive to buy although otherwise would possibly fit the brief, though high grade methanol is not cheap either.   So we have elected for a windgenerator.

We bought one from Marlec, the Rudland 914i.   It comes in a box to be assembled, but only consists of the actual fan.   A suitable pole with fittings is available as an add on but needs stays if mounted on a narrowboat roof and these have to be sourced independently.  The pole is supplied with a pair of mounting plates that permit it to be hinged at the bottom for rapid lowering/raising.   The planning for the installation of this pole caused the biggest headache as the roof would have to be drilled and tapped to install ring bolts so clearly it would have to be in the right position from the outset for the cable run to be possible which again would need the roof cutting.   Reference to another member of Cutweb with experience advised against directly fitting the hingeplate to the roof as transmitted noise could be a problem, so a wooden base plate was fabricated on four rubber feet that could be wedged between a mushroom vent and the roof cross-brace without using any screws.   A small amount of silicone sealant was strategically placed to keep it in place.   Finding a souce of stainless stranded wire stays proved difficult.   A yachty chandlery was suggested as the best option and a visit was made to a large shop at Shepperton.  Ring bolts, turnbuckles, and shackles were available and instead of wire, a proprietory, thin non elastic rope was recommended.  This could be tied and avoid the need for wire clamps.  Electrical wire was also needed and specified by Marlec, 4mm² for the battery connection and I elected for 2mm² for the rest as the run should be short.

Installation took place at Castleford where we were moored for 48 hours and an excellent nearby hardware store proved valuable for the unexpected bolts and other tools that proved necessary.  The longest time was spent on the wiring from the roof through to the regulator and back to the batteries. A waterproof connector was purchased for the roof and this was installed first using a hole cutter.  The route chosen followed the existing solar wiring but was fiddly needing a cupboard door removing for access and a panel from under the gunwale similarly.   However carefully I plan there is always the unexpected and I hadn't registered that the steel bulkhead though to the engine compartment would naturally have a layer of insulation sandwiched between it and the wooden cladding inside.   The wire would need protecting from the sharp steel edge so I had bought a grommet which turned out in the circumstances to be useless.  It needed a pipe pushed through to channel the wire.  Being without an appropriate hole cutter this took some hours and two visits to the hardware store in town.   The second difficulty was the seemingly simple job of connecting the wires to the regulator.   Had the difficulty been anticipated this would have been easier.  The problem was that with the unit already mounted and the connector on the lower edge it was necessary in the end to lie flat on the floor looking upwards to locate the wire in the small holes provided.  Really the wire end needed to be tinned.  One strand always wanted to escape and testing revealed a short circuit.  The 4mm wire had to be thinned down to even get in at all neatly.

Building the charger from the components proved straightforward and assembling the pole likewise.  The ringbolts were soon in place and the thin rope looped back at each end and secured with tightly bound stainless steel locking wire with the double end sheathed in heatshrink sleeving to cover.   Getting the right length for the stays was a bit hit and miss, and a bowline was used initially to gauge the length needed before the final assembly.  The loops can easily be unfastened and altered.   The turnbuckles allow some adjustment for true vertical in daily use and also to release the strain when unhooking.   Normally the generator is stowed forwards, but the "rudder" projects upwards risking damage under low bridges.  If necessary, stowage can be reversed as shown.   Click on images to see a full size version.

 

Reversed stowing position for reduced air draft

Quick release hook for demounting pole forwards

The pole base hinge and mounting board

 

The finished result. Note that the pole is offset to the side. This is to allow forward stowage to the left of the mushroom vents as well as permitting access to the front of the roof by the side.