Gone Outdoors

What Are Bulkheads & Stringers on Boats?

by Will Charpentier

An mnemonic for remembering shipboard terminology goes: "You lean on the bulkhead and stroll on the stringers." Bulkheads and stringers are boat parts that have on-shore equivalents. In spite of their odd names, they serve the same function as their counterparts ashore, as well as add to a boat's structural stability. Knowing that subtle differences marks you as a seafarer when you casually and correctly sprinkle these words in a conversation.

You Lean On the Bulkhead

A bulkhead is a wall. The American Merchant Seaman's Manual says that the bulkhead "provides privacy and encloses spaces within a ship." What the manual leaves unsaid is that the bulkhead is attached to lateral hull stiffeners in the same way that wall studs support a wall in a home. Although most bulkheads are thin, some -- like the collision bulkhead at the front of the ship -- are heavily made to withstand the pressure of the water in the event of a front-end collision.

You Stroll on the Stringer

The stringers are much like floor joists: they support the main deck and decks below the main deck. The stringers also provide room for concealed wiring that might run the length of the vessel. Stringers are concealed by the flooring on the decks below your feet and by the compartment "overheads," the ceilings of the cabins and compartments formed by bulkheads. The stringers provide a convenient attachment point for the overhead of a compartment.

The Bulkhead as a Structural Member

The bulkhead is loosely arranged as a shore-side home's wall, complete with a stud. Unlike a load-bearing wall of a home, the bulkhead doesn't provide structural strength. Instead, the frames that support the bulkhead, called bulkhead stiffeners, add the structure that surrounds a bulkhead. Some bulkheads, though, stand in the way of an invading ocean: should your boat become involved in a collision that breaches the forward end of the hull, the collision bulkhead stops water from entering the boat through the breach.

The Stringer as a Structural Member

Stringers run from the front to the rear of the boat's hull on all sides. One stringer is called the "keel." It runs from the bow of the boat -- the boat's front -- to the rear of the boat in the center of the bottom and acts as the backbone of the ship. Stringers placed between the frames around which a boat's hull is built provide longitudinal stiffness; they also keep the hull from bending in the middle like a rubber raft when the boat rides over a wave.

References

  • "Section 15-01 The American Merchant Seaman's Manual"; W.B. Hayler; 1981

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