Biting midge mentioned sleeping 4.
His family had a Careel 18 by David Rose Yachts. It started off as a Duncanson 18 but developed a sailing scene of all its own - many of the large group of owners are still friends now .. 40 years later. Sleeps 4, sail and motors
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they weren't known as fast boats, but some could sail them much better than others :)
It is worth looking at the next step up. It is a nice family space. But I get the impression that sailing together in an 18ft trailer sailer might have been something that 25 families might do on one weekend 40 years ago.
Now it really is people doing these kinds of things largely solo. The Netherlands might be a bit of an exception with family style sailing in the Valk. Australia, the USA and possibly the UK are mostly people using simpler boats solo, with occasional sailing friends - often not the same ones every time.
I'm writing this down ready to be wrong. But In Australia, the Hartley 16 scene, the Jarcat Scene (a decade or two later), the Careel 18 scene, the Heron Scene, the Mirror Scene, the RL24 scene ... well they were family scenes.
My feeling is it is far too late to try and reinvent something that was wonderful in its era. But for much of the world we are 40 years too late I suspect.
Is that fair?
Are we really looking at a motivated solo builder, who will be a solo sailor with company. Does that seem right for most regions. Or does family style sailing really exist as a niche.
MIK