Mantas, Singles and Twins run as a one design classes in all big NALSA events.
They are usually the biggest classes. As in one design water sailing, the Manta
Class association sets their rules.(Basically, "don't change anything.")
http://www.nalsa.org/Manta/MantaIndex.htm
In general, BloKart runs their own events, so BloKarts seldom run as one design
boats in NALSA events. There are some minor conflicts between BloKart class
rules and NALSA rules, as well as "philosophical differences;" probably not
something that would be impossible to work out if 20 BloKarts wanted to run as a
class in a NALSA event.

--- In 2nalsa@yahoogroups.com, "landsailoz" <landsailoz@...> wrote:
>
> Given that there appears to be no 'one design' NALSA rule, when do the Mantas
and Blokarts run as a one design? Is it a decision taken per event or does there
need to be a minimum number per group or how is it determined?
>