“Mizzens, eh? Not worth the sticks and string!”
Someone of an earlier generation said this about the big racing yawls on the Med circuit, I think . I don't agree. Perhaps for out-and-out speed he was right but there are other considerations, most of which have been mentioned here - or elsewhere on this Forum.
I have found a remarkable difference in the handling of two Lug and Mizzen boats, my CBL “Four Sisters” and a recent acquisition, my Deben Lugger Hybrid “Wabi” . No doubt the BR20, Storm 17, Bj 17 and others have their own quirks. Differences of CLR and CE apart the main influence seems to be to do with the relative size of the mizzen and the mainsail. “Wabi” with a relatively small mizzen, sails happily to windward under jib and mizzen and is equally comfortable with just the main (balanced Lug) sail. With main and mizzen in, say, F5 there is an increasing amount of weather helm.
“Four Sisters” suffers from this, too, but is less than happy under main alone. With the windage on the cabin and only the relatively large mizzen set she will actually creep up to a mooring the right conditions, though. Looks a bit weird, I’m told, but it works. The larger mizzen allows a few other tricks, too. Sailing backwards with just the mizzen set and the sprit boom pulled back over the cockpit, 180 deg to its normal place, for example(useful in confined spaces) and best of all, giving the ability to yank in the mizzen tight, let the mainsheet go and sit dead head to wind taking whatever the sea throws at her - like a duck. “Wabi” despite having no cabin windage to worry about, won’t do this. The “Tail fin” effect from the smaller mizzen isn’t enough to overcome the drag of that dirty great mainsail flogging about. She is happier, and quieter, moving slowly forward with a bit of wind in her mainsail, taking the seas at an angle. Drop the main and you can do the duck thing more successfully. Possibly the underwater profile and massive “barn door” rudder come into play, too. Both boats work better in most conditions with the mizzen but my experience agrees with Julian’s where running down wind is concerned. In anything around F4 and above you have to watch a big mizzen like a hawk to avoid a nasty, skidding broach. I’ve modified “ Four Sisters” with a species of roller furling gear ( a bit of rope wound round the mizzen mast and a low friction pad at the masts foot) so that I can get rid of it as quickly as possible when required, without taking my eye off the mainsail and following seas.
The main thing is to get to know what your boat (and you) can do with various combinations of sail so that you can have the best experience on the water, whatever the conditions.