The previous owner has installed an electric winch on my RL24 previously named Calibre (sail No 303)
It is very convenient and fast and the keel can be raised from the cockpit with a switch.
The time will come when something goes wrong-flat battery and so on so I am looking at a manual system as a backup.
The original system with multiple pulleys is still there but are there easier ways to do this?
A hand winch in the cabin? Or using the jib winches?
Just have a look and see if there is no place on the electric motor for a manual override handle? Most electric winches have them. It all depends if the previous owner installed a proper electric winch, or just a home made electric motor.
The reasons you give are behind the better selection of a hydraulic ram which could be installed to operate thru existing pulleys.
If it not practical to run the hoist to existing winches then a come along winch can help in emergency situations if you can fit it in.
Like this one;
If the pulleys are there for the old winch tackle, surely having a line suitable for threading through the pulleys and hauling the keel up is the simple way to go.
My Mk 4 has a 10to 1 tackle that makes raising the keel a steady chore.
Manually hauling something like the keel takes the same amount of work whether it is a tackle, a manual winch or an electric winch. Its nice to have a battery to provide the energy. Hauling our keel is easy for the first 2/3 of the lift while the bouyancy provides some assistance. I generally stop there and have a rest or work on lighter stuff then head back to hauling the line till the keel is up. When up there is about 10 meters of keel hoisting line stored in the rope bag.
Make sure the line is nice and thick so gloved fingers can get a good grip on the tail while hoisting the keel.