Random Pairs is well known, so let's start there.

Random Pairs is 2 boat team racing (last boat loses) with a twist. The teams are drawn psuedo randomly, and redrawn after each race. [1]
This pairs skilled and unskilled team racers (who may never have met!). The skilled team racer has to shepherd the less skilled team-mate, which is both hard work and excellent training.
The unskilled racer starts to win a lot of races he or she would otherwise have lost, and gets a chance to learn from an expert they would never otherwise sail with.

The winners are the crew who sail in a winning team most often.

Random Triples lifts the core concept from Pairs and applies it to 3 boat team racing.
It has an interesting background. I've been to 3 two boat per team events in the last 5 years where 8 or 9 chartered keelboats were reduced to 7 or less by damage, so halving the number of races for everyone.
Compared to soldiering on with 2 boats per team, Random Triples increases the number of races for each sailor by 50%

It can be played 2 ways, truly random (which is excellent training) or where the competing teams arrived paired up for 2 boats per team and now need to 'mix it' as triples. Let's start with the first:-

1. (Slightly simplified) If there are 7 boats and 7 teams, crews 1, 2 & 3 sail against 4, 5 & 6 in race #1. For race #2, crew 1 drops out, crew 7 joins in and every boat moves up one place. However, to avoid 2 & 3 (and all such pairings) sailing together too often crews 3 and 6 swap sides - but not boats. So the second race is 2, 6 & 4 vs 3, 5 & 7. A full round robin is 7 races, each crew sailing 6 of them.
   If there are 7 boats the 7th boat can be crewed and ready to race, so minimising delays. If there are only 6 boats, only one crew changes between races. Either way, 2 crews have to change their identifying markers over [2].
   After everyone has sailed the same number of races the winners are the crew who sail in a winning team most often.
2. Here's the twist if teams arrived expecting to sail 2 boats per side. Firstly, the rotation prevents team-mates sailing together. This is only fair, or there are mixed motives when the 3rd crew comes from your strongest opponents! It's also part of the fun to buddy up with crews who were previously rivals.
   A full round robin is 14 races, in which each crew sail 6. It's best to sacrifice a bit of time and change the active crews every 3 or 4 races. Otherwise half the sailors have nothing to do until the first 7 races are over.
   The winning team is the one whose 2 crews sailed in a winning team most often.