Hi Michael, thx for the answer.

Finally I changed the drawing to a no units system, and it was very quickly, without problems! :-)

Anyway, if this is useful for you, when I was trying to change the units to meter, before the crash, the file is aprox. 90 mb, and it was using about 500 mb of RAM (I have 2 Gb)

About the balustrade...the problem is in the angle or number of polygons when I´m exporting the file. The problem is the same in n-gons and quads&triangles. The thing I can´t understand is why it´s happens only with those balustrade. The rest of them looks more fine.
I have remade those balustrade and I only obtain a straight shape. I have made the balustrade extruding a rectangle using the edge of the hull under this balustrade like path.
If I increase the values, I obtained a heavy model. Well, I can select only the balustrade, and export with other parametres, but I don´t know if this is normal.