[ccriders]

Maybe a real navy cockswain can help out here. I once observed a navy competition of precision boat driving. It was much like a poker run, but there was no chance element and speed was the ability to maintain precise speed of your craft, differing for each leg.
You could turn this concept into a boating rodeo where several seamanship skills are involved going to and arriving at precise locations at precise times, tacking drills through a chicane, etc. disallow GPS and plotters - compass and chart only. You could have many stations and send boats out in different patterns, maybe pairing like boats. By putting precise speed vs max speed into the equation you could have all the boats returning as a fleet, raft up and party while the judges tally the results.
A varient would be instrument sailing, where the helmsman follows course and speed instruction from a navigator who is blinded to the outside world. That might be too difficult for the size boats you're talking about.
Just thinking...
John

 

[ccriders]

After reading Pendragon's post I thought about how pilots learn to fly close together. Maybe you can have a set of events where people learn how to sail in formations. Start with two boats and build to a larger fleet as experience grows. You would need experienced coaches and communications between the boats so everyone knows what's going on. You could work through some examples of racing rules in specific situations like overlaps, windward/leeward, etc.
Can I join your club? Sounds like fun,
John