Re: Windlass?
You should have chain on the anchor rode. If you go with a chain/line combo, the usual estimate is to mirro the amoun of chain with the length of vessel (20' boat = 20' chain). Be aware though, that this can change depending on the source of information, area that you're boating in, type of vessel being anchored, weather, etc. I would consider equal length a good starting piont.
The purpose of the chain is to keep the shank/shaft of the anchor lying flat against the sea floor or lake bottom. This helps in keeping the flukes buried deeply in the bottom.
Depending on the type of windlass you have, they are usually configured with chain link cut-outs (for lack of the best term) at the bottom of the spool. Above that. there is a stairstepped pulley which can accomodate various diameter of line. If you Google the model of windlass, you will get the recommended size chain link and rode diameter to use for your windlass.
Replacing the line is pretty striaghtforward. You shouldn't have to do anything like taking the windlass apart. Some have a "claw" apature that holds the line against the spool, but that just lifts up. Remove the old line, run the new line through the windlass (most have a freespool setting). Don't forget, somewhere at the end of the line, it is secured to the boat so that is doesn't totally disappear when playing itself out.
