As it was a bit far and too cold to swim, yes they did travel by boat!
You will find a partial index to departures from Tasmania on the Tas. Archives website, but as they say "Records of people departing were not routinely or comprehensively kept at Tasmanian ports". Mant entries note the ship of arrival to the colony and the "status" of the passenenger (free, pardon, COF).http://portal.archives.tas.gov.au/menu.aspx?search=2http://portal.archives.tas.gov.au/menu.aspx?search=2
A convict with a ticket of leave would not have been departing Tasmania, not legally anyway.A ticket of leave simply meant that they could work for themselves instead of being assigned but were restricted to staying within a designated area and had to attend musters and divine service.Only convicts with a certificate of freedom or a conditional or absolute pardon could leave Tasmania.