The most common translation will probably be "Querschnitt". This is any view that shows how an object would look cut in half, usually along a central vertical axis.
You can say "Seitenquerschnitt" to emphasise that this is a side cross section, but since this should be rather obvious in your case (unless you're designing a very unsual yacht) it will sound like "side cross section seen from the side (not from above or below)" Duh! :)
"Seitenansicht" and "Seitenriss" both mean a mere "side view" that does not reveal the interior.
If you're talking about a building, "Aufriss" is correct ("elevation" - also usually not showing the interior). "Grundriss" is a building's floor plan.
"Sektion" is more or less correct, but rarely used - sounds rather medical to me. I wouldn't recommend it.
"Ausschnitt" usally just means "detail" but can sometimes refer to a bit of the object being cut away to show the interior. But this is never a cross section - I suppose you'd say "with a section of the hull removed" or something.
"Abschnitt" means "section" in the sense of "part".