3 man trapeze boat!?!?!

3 man trap on the river in shifty breezes - how many tea-baggings are you going to get from that?! Sounds fun - to watch...

I don't believe the Raters sail with strings on the river. It would scarcely be practical anyway because, certainly when I've sailed at Thames, the wind tends to funnel down the river so you get beats or runs and very short tacks.

Hobie built the 21, 3 man Cat with 2 trapeze wires, park benches mounted either side. I don't think many were sold outside the US.

I actually think the SB3 captures the market really well, else, you are really looking at an 18. Alternatively, find your third person a crew/helm and get two 49ers, 800s, etc. There may be more fun in having two double-handers to race against each other than an obscure tripple hander. As you remove the complexity of an 18, you're going to tend to something along the lines of an SB3 to keep the performance alive and practicality. For what it's worth, I'd quite happily have an SB3, very attractive package and excelent racing. Just don't have enough cash at the moment, but such is life.

You're going to need a lot of water to sail such a beast in anyway... so I think the cat idea has some legs but agree, there's isn't enough volume in it to interest one of the big builders, a 3 person dinghy won't reach SB3 sales volumes IMO. 

The cat platform means you could have just one mast that stays up all the time (rather than seperate rigs skiff style) and either reef, or have different sail combo's, to accomodate low/high wind occassions, it will also provide a big enough platform for 3 to sail without crashing into each other, while avoiding the need for wings, bars, seats or whatever which would probably be needed on a monohull although I don't think Oz 16ft's have wings or perhaps didn't once upon a time but do now? There's probably enough power in an F20 rig for 3 people to sail one right now, 2 on wires, 1 on helm hiking.