Tuesday, 19 August 2014

Auto Pilot ?

Vagabond is still in the barn. The rubbing strips have been rubbed (down) and varnished - to say that they look like new would be overstating matters - they look considerable less scuffed. The hull and deck has been washed in Bucks spring water (courtesy of the farm supply) and even polished. The scrapes and blemishes remain and will need fixing before the weather gets too cold the gel coat to set properly. The trailer wheel bearings have been identified and one of these days I'll be brave enough to jack up the trailer and start inspecting them and the brakes.

But a new project beckons. One of the things that's been limiting the distances that Vagabond can travel in a day (apart from rule (b), that is)* has been the strength or endurance of my tiller arm, for Vagabond has no auto pilot beyond a couple of pieces of string to "lash the helm". This means that the cockpit can't be left for any length of time unless we are hove to.**

What we need is an autopilot - the snag is that most of them consume battery amps to make the tiller move - battery amps are another commodity in short supply at sea.

Browsing the local newsagents for yachting magazine (just to look at, not to buy, you understand) I found an article about a home made wind vane auto pilot. ,

So I bought the mag and was smitten. It uses energy from the speed of the boat through the water acting on a second rudder as a power source to pull ropes attached to the tiller arm to correct the course to keep the boat on a constant course with respect to the wind.

I've been in contact with the designer, John Fleming *** and am slowly considering whether or not to purchase the plans or the kit.  I wonder if I could convert it to turn a trimmer on the tail of the rudder rather than ropes to the tiller arm....

Watch this space. The Channel Islands and France may be within reach after all....

* see the previous posting
** Technical term meaning stopped in the middle of the ocean with the foresail and the main sail sort of opposing each other, so that all the boat does is drift down wind and wallow in the waves.
*** I've sent him lots of questions by e mail and had informative replies. You can see details of the Hebredian wind vane at www.windvaneselfsteering.co.uk


  1. I have a Raymarine ST1000 on Drascombe Coaster and run it off a 80ah AGM battery. I also have a Garmin 451 chartplotter, depth sounder and charge a mobile phone and tablet. A battery charge lasts about 4 or 5 days until the battery is down to about 11.8 volts. At the moment I recharge in marinas. I have been considering solar panels. Have you thought about solar panels on your Baycruiser 23. You seem to have a large clutter free area on the stern of your boat suitable for panels. Wind vane steering always seem to clutter the boat and spoil the beautiful looks of your Baycruiser.
    Ian Cowie

  2. Hi Ian

    Thanks for your comments. I do agree with you about the clutter that a wind vane adds to the stern of a boat particularly as they all seem to need a pushpit on which to mount the various pulleys and bits of string.

    i've always been a bit paranoid about amps which is why Vagabond carries two 50ah batteries wired in parallel, without any diode cross linking. For the first couple of years she had 2 x 10 watt solar panels on the aft deck behind the cockpit. As evidence of my paranoia, I added 1 x 25 Watt panel on the cabin roof for this summer.

    Despite this array, running a small Garmin charter plotter (456?), tactix depth sounder / wind instruments and a Standard horizon VHF (admittedly one that detects and plots AIS signals) depletes the batteries to the extent that on a dull day, even after a full overnight charge in a marina, the volts are down to 12, before the IPad is recharged.

    This summer, when I knew I was going to be away from a mains supply for three of four days whilst sailing south from Stromness, I took the risk of running without the VHF. We were a week without connecting to mains power ( two of those days were spent lying alongside, so consumption was nil and the Ipad was charged in the local pub). By the time we reached Mallaig the volts were down to 11v.

    This winter i intend to change the wiring to make each battery independent. I have a solar charge controller that can deliver it's output to two separate batteries and I'll install a switch so that I can run off either battery. My thinking is that I can use the batteries on alternate days and the arrangement will show up if one of the batteries is not performing well.

    But I'm still pondering the wind vane autopilot question.....

  3. Rob,
    That is a disappointment. My Autohelm only uses 40ma on standby and between 0.5A and 1.5A in use depending on the sea conditions. I reckon that on a Coaster which is relatively lightweight that it would not use the full current. The ST 1000 is designed for boats up to displacement 3000kgs. I must admit that I rarely use the Autohelm for a full 6 to 8 hours on a daily trip. I use the Autohelm to release me from the tiller and allow me to eat, navigate, use my camera or binoculars. Also to make adjustments to the sails, rigging and getting to come along side, fenders warps etc.
    The biggest drain on the battery is the Chartplotter, phone/tablet charging. Solar panels do not seem to be the complete solution especially on a small boat where shadow free deck space is at a premium.
    Electricity and small boats do not seem to go together.

  4. Ian,
    I've taken both of my batteries out for the winter. Therre 40 Amp Hour, not 50 and one of them is not accepting as much charge as the other, which I think has degraded the overall performance of the system. I think that, if two batteries are connected in parallel, they should be connected through a bridge rectifier, wired so that one battery does not discharge the other.. I'll try that next year.