We spent 6 months there, with the van. Could have done with even longer. Due to family in Tas I have done a number of Bass Strait crossings, over the years, and after the first couple (in my resilient youth), the only way I go now is in a cabin with private facilities. I do not get seasick but there is nothing worse than having to mix in with a shipload of seasick people - or having to use the bathrooms after same.