Hi all the Flytron device arrived this morning it is the same size as the socket part of a servo plug!
It is called a servo expander circuit. £8.85 + p&p £2.50
http://www.flytron.com/Tested it on a few servos and it extends the rotation to about 160 degrees which is great for a yacht sail arm winch.
So with a cheap metal gear Tower Pro MG 965 servo, sold as 180 degree type, I bought 3 for less than £10.00 I have a small and quite powerful sail arm winch. Finger crushing at servo edge.
I will explore later the transmitter option but the expander circuit does keep the system standard and not needing a specific Tx. for the job.
Thanks for the input guys I think that unless you buy a dedicated yacht winch, you will have to use an expander or stretcher circuit to get the extra rotation. This changes the standard 1 - 2 milli second pulse width to 0.5 - 2.5 milli seconds.
I bought servos listed as 180 degree rotation not knowing you need the change to a wider pulse width to get this rotation.
I do not know if computer Tx's already have the facility but most times I use just 3 channels.
regards Roy