29 CFR §1918.25

1. (a)Bridge and car plates (dockboards). Bridge and car plates used afloat shall be well maintained and shall:
   1. (1)Be strong enough to support the loads imposed on them;
   2. (2)Be secured or equipped with devices to prevent their dislodgement;
   3. (3)Be equipped with hand holds or other effective means to permit safe handling; and
   4. (4)Be designed, constructed, and maintained to prevent vehicles from running off the edge. 3
2. (b)Portable ramps. Portable ramps used afloat shall be well maintained and shall:
   1. (1)Be strong enough to support the loads imposed on them;
   2. (2)Be equipped with a railing meeting the requirements of § 1918.21(b), if the slope is more than 20 degrees to the horizontal or if employees could fall more than four feet (1.22 m);
   3. (3)Be equipped with a slip resistant surface;
   4. (4)Be properly secured; and
   5. (5)Be designed, constructed, and maintained to prevent vehicles from running off the edge. 4