Utterly Mad

Dig a long hallway and dig several rooms along each side. These will be used as workshop areas where production will take place.
Set the now on-land ships as the sleep areas and stockpiles till those rooms are ready to be moved into.
Cut down the masts of the ships and use that wood to begin the construction of several basic workshops such as carpentry, fishery, butchers, stone working, tanning, and leather working. These will be placed in the underground rooms being dug out.
Several scouts will be sent inland to see if a better supply of wood can be found since cannibalizing the ships won't last forever.
Keep patrols of armed guards stationed around the underground entrance way, the ships, and the water front.