TM 55-607/NAVSEA OP 3221 Rev 2
1. THERE ARE NO OBSTRUCTIONS IN DECK
Figure 10-16. Top view of a typical YFN lighter.
Figure 10-17. Side view of a typical YFN (modified) lighter.
c. Open the hatches on the YFN and modified YFN lighters.
10-9. Dunnage Requirements
. Sheathing (fig 10-18)
to separate the ammunition cargo from the steel structure
barges. Since the bulwark of the YC barges and the ribbed walls of the YFN barge deckhouses do not present a level
shoring surface, the following sheathing procedures are recommended for YC and YFN barges:
(1) For YC barges, smooth sections of the steel bulwark may be sheathed with vertical 1by 6-inch boards.
Openings in the bulwark may be shored with three horizontal 4 by 4's and 2by 6-inch minimum vertical boarding to
withstand cargo forces. When barge load limits permit cargo to be stacked higher than the bulwark, the perimeter
shoring and sheathing functions can be combined into one structure. When cargo height exceeds the bulwark by more
than one-half of the top unit load, perimeter shoring of 4by 6-inch uprights, spaced not more than 36 inches apart, should
be erected. Face boards of 2by 6-inch, minimum, should then be attached to the uprights at a spacing not to exceed 24
(2) Since the steel deckhouse walls on YFN barges are not strong enough to support the loads imp sed by the
ammunition cargo during severe sea conditions, sheathing structures must be designed to transmit these loads directly to
the main structural beams of the deckhouse. Two different methods of sheathing YFNs are currently in use, although
both depend upon transmitting cargo forces to the three horizontal beams that are part, of the deckhouse walls. One
method calls for attaching 4 by 4's to the horizontal beams with steel strapping. Then 2by 6-inch, minimum, face boards
are attached to the 4-by-4's at a spacing not