Editing Lock (water navigation) (section)

===Snubbing posts===
[[File:Snubbing a boat C and O Canal 1.jpg|thumb|Snubbing a boat to keep it from hitting the downstream gates. Note the rope wrapped around the snubbing post.]]
On horse-drawn and mule-drawn canals, snubbing posts were used to slow or stop a boat in the lock. A 200-ton boat moving at a few miles an hour could destroy the lock gate. To prevent this, a rope was wound around the snubbing post as the boat entered the lock. Pulling on the rope slowed the boat, due to the friction of the rope against the post.<ref>Kytle, Elizabeth. ''Home on the Canal''. 1996. {{ISBN|0801853281}}, p. 133</ref> A rope {{convert|2+1/2|in|cm}} in diameter and about {{convert|60|ft|m|abbr=off|sp=us}} long was typically used on the Erie Canal to snub a boat in a lock.<ref>Garrity, Richard. p. 41</ref>

One incident, which took place in June 1873 on the Chesapeake and Ohio Canal, involved the boat the ''Henry C. Flagg'' and its drunk captain. That boat was already leaking; the crew, having partially pumped the water out, entered Lock 74, moving in front of another boat. Because they failed to snub the boat, it crashed into and knocked out the downstream gates. The outrush of water from the lock caused the upstream gates to slam shut, breaking them also, and sending a cascade of water over the boat, sinking it. This suspended navigation on the canal for 48 hours until the lock gates could be replaced and the boat removed from the lock.<ref>{{cite web|url=http://www.nps.gov/history/history/online_books/choh/unrau_hrs.pdf|title=p. 812|website=nps.gov|access-date=21 September 2018}}</ref>