Dobbs, when I was sailing La Grace we did 5 knots with the wind on the beam (90 degrees) and a relative wind speed of 15 knots with only three sails set. (All on the foremast and not well trimmed either.) I´d say we were in the "backing sails" category. La Grace is a typical 18th century brig. According to her captain she's always last in the tall ships races until the handicap is applied. She's also one of the oldest (in what is replicated and how closely).

Tre Kronor (1840s, steel hulled) when running felt like there was no wind at all. She wasn't much slower than the wind. I can't remember numbers but there was an easily noticable difference. I guess the best sailers of the napoleonic wars would still be worse than Tre Kronor. Her captain told me he'd had her go more than 17 knots momentarily.


On the other hand if we're looking at Trafalgar...