Boatlength

His failing form the tides wash o’er, / Within a boatlength of the shore.

Source: wiktionary

Philip was rowing nervously, two boatlengths behind, and the others had given up the race, and were paddling near the banks to talk with their friends.

Source: wiktionary

The men dropped their ropes and jogged away from the front of the collier. Bartlett guided the collier back to the mouth of the harbour and gave her full throttle. His momentum split the ice and carried him in a few boatlengths.

Source: wiktionary