Introduction
The basic idea behind the series scoring is that we add together each member's scores from the individual races of a series, and whoever has the best total is the winner.
Races to Count, and Discards
We need to make a few adjustments to make things reasonable and fair. Our standard series run for thirteen weeks, and we don't expect people to be able to make every single race, so we don't want to penalise you for missing a few races: we want to recognise performance rather than just attendance. We set up the scoring software so that it counts only the best half, or so, of each competitor's scores.
(It's actually half the number of races scheduled, plus one; the remainder, known as "discards", are ignored, and that gives a reasonable allowance for disposing of your DNC scores.)
Finding the winners
When we have totalled up all of the "counting" scores, the boat with the best total is the winner. (And, as we are using the low point score system, best means lowest.)
If two or more boats are tied on their totals, we follow the tie-break procedures of the Racing Rules (RRS.A8): first we compare how many firsts they have, then how many seconds, etc., until we find a difference, and if we don't find one, we start again, comparing each boat's most recent result (this time including the discards), and then going back to the previous ones, and so on, back in time. That's pretty much guaranteed to find a difference.
Changing your boat
All the above assumes that you use the same boat (or at least the same class and rig option) throughout the series. If you use more than one type in the same series, you will be scored with two (or more) separate entries to the series, as if you were different people, and then all the above applies to each of your entries.
If you use a boat that has more than one rig option, with different PNs for each, you have to declare which option you are using for the series. You can at any time use a slower-rated option than this, particularly when advisable because of stronger winds - it's the same with reefing, on classes where that's available. But you can't use a faster-rated one, unless you open a separate entry for it.
Duty credits
We give credits for duty activities, to make sure people don't lose by taking them on. But it can cause distortions: in an extreme case, you could win a series by getting a single good result and then doing a lot of duties. It has happened! So once you have done three duties in a series, any further ones are not credited.