I must throw in a new design from
Scotland for the consideration of servo pendulum users. The inexpensive kit (currently only £300 sterling + delivery) provides materials to make the 'Hebridean' (
Self-steering Servo-Pendulum Wind Vane Kit & Plans for DIY Kit for Sailors | www.windvaneselfsteering.co.uk) with basic tools. It is part
wood, which you source yourself. Obviously the
price alone makes it worth a look to anyone on a
budget.
I am able to share that I was John Fleming's (no Oz relation) customer number one in the autumn of 2013. I built my vane over the
winter and tested it on my old 1979 30 foot fin and skeg
boat in February 2014. Since then I sailed to St Kilda and the Faroe Islands this season (see Practical
Boat Owner September 2014), the latter solo, with my new servo pendulum crew
member. I really like it!
But there is something more important about this vane. And it was not easy for me to understand till recently. A feature of the geometry is John Fleming's principal innovation, which has allowed such a unit to be built for the first time with a truly horizontal vane axis. Perhaps those here will be able to explain better than me why that is important. Suffice it to say that it largely eradicates many issues associated with units using an axis 20 degrees off horizontal by allowing air pressure to bear on the vane through its full
arc of travel, instead of pressure reducing as the vane goes over. Hence the Hebridean needs no bearings to reduce friction and has greater
power in all winds, light or strong. Maybe read that again.
A radical claim I know, as I understand the industry abandoned pursuing the truly horizontal axis solution decades ago — back in the early days of servo pendulum development.
This solution is easy and
cheap to build, having no bearings or welding. It is robust but would be easy to
repair. Possibly
cheap and light enough to carry two! It is all 316 stainless except for the tubes and rods which are carbon fibre. (You also need to find your own foam and covering material for the vane, which is built on a carbon fibre tube frame.) It is light and can be demounted by hand under way and stored, but fits any boat with a transom up to 39 inches (1m) in height. The important part is the geometry which I believe could be used in alternative sizes or materials of choice.
I met and have sailed with the
designer but have no financial interest in the product. I do however encourage you to have a look...