Which of the more or less standard solocats (HC17, HC FX one, Nacra I17) or cats that can be easily managed with unirig (5.5SL, F16?..) has the most buoyancy (regardless where it is located)?

Bart

Why are you asking ?

Wouter

Do you mean the maximum hull displacement (the total volume of the hulls x weight of water)?
Or the maximum crew weight before performance suffers too much?
Some boats tolerate additional weight better than others.

There is also the A Class, the 18 Square Meter Class, the Nacra 450 & 500, and the Mystere 4.3.
The Nacra 5.5 was also built as a Unirig.

The nacra 5.5 has tons of volume in the hulls compared to the rest on your list.

Of the three you listed, the I-17 has the best hull volume. I have seen it sailed with two good sized adults and do quite well.