I have never conciously used the ratchet mechanism on my H18 mainsheet.
Do you use it? Under what conditions is it useful?
I use it most of the time, especially single handed. When tacking there is lots going on when I'm solo. While steering through the tack with one hand, I can use the other to reach down,grab the jib sheet, give it a yank, let go, reach ahead & give it another yank. The ratchets will hold some tension, & prevent the line from just playing back out.
If you have ratcheting on your main, it will take some of the load from your hands. I don't cleat the main in windy conditions, but if you are in no danger of tipping, the ratchet will hold quite a bit of the load. It makes it less tiring on long sails. Out on the wire, you have the tiller in one hand, the main in the other. By only having to hold 1/2 or less of the "pull" your arm does less work.
I use mine in everything except really light winds. Otherwise why work harder if you don't have to?
I've never used my either. So, if you need to dump the main (in a big gust or to stop a pitchpole or something), does the ratchet make this more difficult? Can you adjust the amount of tension on the line before it grabs?
I need to figuire mine out too, seems like I'm in and out of the cleat all day.
Some are adjustable, I think the Ratchamatics are adjustable but the hexaratchets are on/off (don't recall I've never adjusted mine).
Basically it provides extra resistance to letting line out (up to 10-15 times depending on the ratchet). When trimming in the block turns, when letting out the line slips so it is more difficult to let out. In light winds the sail won't give you enough force to let out the block but in medium to high winds it is never a problem.
Dave.