Dinghys with keels

Not sure where to put this one but I was watching the 2.4s training on Sunday in 15-20 knots and thinking about Eric Twiname's classic bit of dinghy advice about sailing the boat flat. Obviously the 2.4 is a full on keelboat so I assume the hull form is designed to sail well at 45º+ of heel. Dinghies are designed to be most efficient with less than, say, 5-10º heel. So what about 'dinghy keelboats' like the VXOne (and bigger 'sports boats' like the Melges 24 et al). I guess their hull shapes cover the spectrum from VXOne (pure dinghy hull, hiked like a dinghy, best sailed flat) and optimised for increasing angles of heel as they get bigger and crew weight becomes a smaller percentage of the whole?

Yes, that's what I was thinking, Ultra 30s and their ilk being an extreme case in one direction. It was a reference to the VX-One and looking at the Yachting World video review that set me thinking today. Just a skiff with a bit of lead in the daggerboard by the looks of it.

I think the OP knows that...

I seem to remember that Paul Handley designed the K1 to work well when heeled. Bet they sail them flat, though! The rig must be more efficient upright even if the hull is good heeled.

My take is that a fixed (i.e. non canting) keel has zero righting moment when the boat is flat/upright so it's impossible to sail a keelboat flat without moving ballast (or 'crew' as it's known) on the windward side. Even in a drifter there will be a little heel. The effect of the ballast will depend on a number of things including how far from the centreline they can get and weight relative to the displacement of the boat and it's ballast ratio. So 10 blokes wiring of the racks of an Ultra 30 make a huge difference but a couple sitting on the windward rail of a J24 have a relatively small (but obviously still useful) effect.

Those Vendee Globe boats look like huge dinghies when their doing 25 knots + off wind. I wonder how long it takes to tack one...... the list of tasks must run :- pump the ballast from one side to the other, cant the keel, lift the windward daggerboard and lower the leeward one, turn the boat and re-sheet the foresail..... And probably several other jobs too.