Originally posted by luponix:

the easiest fix for this would be to just allow placing boats within the vicinity of a leviathan

My boat have been destroyed exactly 'cause I moved it too near to the leviathan, with the storm going on: it gone over the giant monster's back, then fell back in the sea... upside down (a mechanic I like and I don't want to be changed: it was me to fail, thinking I was able to board the beast even with the storm, so I paid seeing my boat to sink, that must remain).

The only solution I can think about is the one I wrote in the 1st post: to be able to place a workbench, and to build over the leviathan's back (if to place a portal) or to use the workbench to deploy a raft (if one have such materials at hand).

P.S.
there is a way to reach a landmass even having materials for a cart: it's mid way between cheating and "mechanics abusing" but it works. It only needs a workbench to be present, for cart deployment.