Quote from Splatulated;1257693:
wut o.o
It's a Sims joke. All (or at least, almost all) of the Sims games have somewhere in the bullshit loading screen messages about "Reticulating Unreticulated Splines". The loading screen messages are nonsensical phrases for humour purposes.
If you want to place a pirate ship, you have to be on a beach lot. It's under special lots when you can place lots in the neighbourhood, but only some neighbourhoods have a road configuration that will allow a beach lot. For example, Pleasantview's layout will not allow a beach lot, because the closest road to the water runs perpendicular to the beach line.