Only problem is the motor only switches on at full rudder left or right. So looking at it logically it should have two servos. But I may fit an esc so that I can fully control the motor at all times. The motor runs okay from 1.5 volts up to 6 volts. So now need to know what esc to look for. Cheers Colin.

The servo is a twin linear, as you can see, one lug operates the rudder, whilst the other moves a lever that connects power from a battery to a small moter driving a prop.
The lever is a simple on/off switch, no speed control or reverse, the motor is either on or off & is to get the yacht back if the wind drops.

Hi Doug, and anyone else reading this post sorry for the delay.
Managed to get boat out of trailer today, see the photos and you will notice my concern. I think that it really should have another servo. have powered the motor, it takes 2 AAA batteries, 3volts.the sweep switch that is connected to it is just forwards and backwards, not sure about the servo as haven't removed it yet. the connector to the RX is rather big with 3 pins not sockets with red, black and purple wires. All input gratefully received. after much research managed to ascertain that less than a 1000 came into UK in the early 1970's
Cheers all, will be at WMBC display on Sunday with a trailer full of my boats.
Cheers to all Colin.

Evenin' Colin, await developments with interest.
Give me some pics of the servo and it's plugs and maybe I can identify it.
Several years ago I found some ancient linear servos at a Flea Market. They had unusual round 6 pin plugs I had never seen before 😲
I took 'em apart and rebuilt them as radar scanner drivers 😁
Have a good show, pics??? Best regards, Doug 😎

Will borrow a laptop tomorrow and post details and a picture or two. Yes Doug it is a linear servo, but need a receiver to try it out as it doesn't fit my servo tester.must figure out an adapter.
I'll have to wait till I've been to the show this weekend, as it's already packed away in my show trailer.
Cheers Colin.

Hi Colin that does sound a very strange set up for a yacht , if you could post some pictures up of the insides it will help us to help you to get her up and running again.

Evenin' Colin, Got any photos of the internals ?
"Two sliding lugs" sounds like a linear servo!!
What kind of switch, micro, toggle or slider?
Sounds odd whatever the switch is😲
Drive motor or winch motor ?
Cheers Doug😎