from
The Collaborative International Dictionary of English v.0.48
Underrun \Un`der*run"\, v. t.
To run or pass under; especially (Naut.), to pass along and
under, as a cable, for the purpose of taking it in, or of
examining it.
[1913 Webster]
Note: The cable passes over the bows and stern of the boat
used, while the men haul the boat along by pulling upon
the cable. --Totten.
[1913 Webster]
{To underrun a hose} (Naut.), to lift it up at one end, then
walk along shifting one hand after another so that the
water will run out.
{To underrun a tackle} (Naut.), to separate its parts and put
them in order.
[1913 Webster]