Arrr. Mister Fastrider be a butchering the queens English. Arrr.
It be land lubber, not land lubbing.
Google it me maities and ye\'ll be gettin this:
lub·ber (lŭb\'ər)
n.
A clumsy person.
and this:
The word *landlubber*, first recorded in the late 1690s, is formed from *land* and the earlier *lubber*. This *lubber* dates from the fourteenth century and originally meant \'a clumsy, stupid fellow; lout; oaf\'. By the sixteenth century it had developed the specialized sense \'an unseamanlike person; inexperienced seaman\', which is the same sense as *landlubber* and was eventually combined with *land* to emphasize the unfamiliarity-with-the-sea aspect.
*Lubber* itself is probably related to or derived from *lob*, a word also meaning \'a clumsy, stupid fellow; lout\', which is chiefly an English dialect form but occasionally appears in America (for example: \"He is generally figured as nothing but a lob as far as ever doing anything useful...is concerned\" -- Damon Runyon). Though *lob* is not found until around 1500, somewhat later than *lubber*, *lob* is clearly related to words in other Germanic languages meaning \'a clumsy person\'.
From The Mavens\' Word of the Day (October 9, 1997)