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By Bruce Beveridge

Excepting tankers, most vessels of medium or large size have their exposed decks covered by wooden decking; the wood may be laid over steel deck plates, or may rest directly upon the steel beams and stringers.  Teak wood decks are the finest, and are seen on all good yachts; yellow pine is used for many commercial and naval craft, and white pine, fir, spruce, and cedar are also common.

MARGIN PIECES. - The wood decking of large vessels is separated from the side of the ship, or bulwark, by a gutter way.  The outer boundary of the decking is formed by a wide plank, which is variously known as a plank sheer, margin plank, or as on wooden vessels, a covering board.  Other wide planks are also fitted around hatches and scuttles, at transverse boundaries, and as foundations around barbettes, winches and other machinery.  These margin pieces should, when possible, be teak.

TYPES OF DECKING. -  Two styles of decking are in general use.   In one, the strakes of deck planking are arranged fore and aft, parallel to the centerline of the ship.  At the ends of the ship, where the deck narrows to more of less of a point, the ends of the narrow planks are nibbed into the inner edge of the wide sheer plank, the latter having a series of corresponding notches.  In the other style of decking, the narrow planks run parallel to the margin plank-i.e., follow the plan contour of the ship while their ends are nibbed into a wide center piece known as the king plank.  The latter arrangement, common to nearly all yachts as well as many passenger and naval vessels, is attractive to the eye.

The arrangement of wooden decking over a steel deck as in figure 1. is typical of that on many ships.  In this case, the steel decks are lapped and riveted, but the laps are not joggled.  Hence, to provide an even under surface for the wood decking. Lining strips have been arranged as shown, the liners being held by countersunk rivets extending through liner, plate, and beam.  The wood decks are held in place by bolts attached to the liners.

Figure 2. Shows decking arranged in a simple fore and aft style, the plank ends being nibbed or "stepped" into the margin plank.  Beneath the margin plank is a narrow plate of similar contour, called a stringer plate, which serves to tie the decking to the sides of the ship; it is overlapped by the margin plank a distance of two or three inches.   Other margin pieces of wide plank are also shown about the small hatch opening; and here again the use of steel plate at a deck boundary is illustrated.

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CONSTRUCTION UNDER BITTS- The use of specially shaped, wide planks, serving a similar purpose to margin and king planks, is shown in Figure 4 through 6.  The bitts in Fig’s 4 and 5A are situated at an angle to the fore and aft decking, and the use of nibbing is clearly indicated.  The bitts must, of course, be strongly secured, and it is usual for their long fastening bolts or rivets to pierce a heavy doubling plate which is riveted to several beams beneath wood, steel, or wood and steel deck.  The use of a header, consisting of a heavy I-beam or channel arranged in a fore and aft direction between deck beams, is also common beneath bitts.
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LAYING THE PLANKING- The fastening of the deck planking is most important.  It is customary to cut, shape, and fit the wood in place, and then to squeeze the planks to each other by means of dogs and wedges, before drilling the bolt holes. This work may be carried out as in Figure 6 where the decking is seen laid upon a 3/8" filler strip, which in turn rests upon the flange of the deck beam.  The squeezing effect is obtained by the wedges, as shown, bearing against the dog, which is formed from a piece of angle bar; the small triangular plates fastened to the ends of the angle dog serve to keep it in proper line upon the beam flange.  The dog may be set at any desired spot upon the beam by the use of the bolt.
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The decking being tightly held, the bolt holes are drilled from below, the previously punched holes in the flange of the deck beam guiding the drill.  After the holes have been drilled through, they are counter boared from the top side of the decking so as to provide countersinking for the bolt heads and deck plugs.  This counter boring is done to a certian depth, regulated buy the gauge.  An improvised gauge may consist simply of a small square of hard wood, drilled, and set at the desired distance from the point on the bit.  The bolts are usually driven from the top until they are hard down and far enough through to secure a nut, although the bolts are sometimes driven from beneath; in such cases, the slotted nut, turned by a large screwdriver of the tee-handle variety, is covered by the deck plug.  When driven from above, deck bolts should have a small grommet made of lamp wick, soaked in white lead, under their heads.   If driven from below, the nut should have a similar grommet. The nut being set up hard, the wooden plugs are dipped in white lead and driven in; they are arranged so that their grain runs the same as that of the decking; they are, of course, of the same material.
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CAULKING- Deck caulking tools and methods are illustrated in Figure 7.  The caulking or "making" tool A is used to drive the oakum into the joint or seam, after it has been opened by the deck or "dumb" iron B.   The bent tool C is also used for opening joints, while the narrow "spike" D is used in caulking small joints.  Joints are cleaned out by the clearing or "reefing" tool E, and the sharp or "butt" tool F is used as a chisel in enlarging a butt joint to proper width and depth.  The peculiar, long-headed, wooden maul used in striking these irons (not shown) is called a "beetle".

The technique or, more properly, the art of wood caulking is beyond the scope of this article; and such variations of method were in effect in different yards and in different countries.  Any attempt to lay down rules or instructions will invariably invite criticism.  Briefly, in large-scale deck caulking, as on passenger vessels, the seams are first opened up with a reaming iron and, being properly clean and of sufficient depth, are partially filled with cotton spun yarn. Next, a layer of oakum is driven on top of the cotton, as at G.  Further driving may be carried out by two men, one swinging a maul and the other the "hawsing" iron J. Finally, the caulked seams are filled or "payed" with pitch, poured from a special type ladle H, a cross section of the finished job resembling that of I. One thread of woven cotton, followed by two threads of oakum, suffice for new decks or decks in good condition aboard most commercial vessels, but widely varying quantities are used in special cases.   Most small craft use only cotton.

CANVAS DECKING- The upper decks of some passenger vessels, ferryboats, and cabin tops of some yachts, consist of tongue and groove planking covered by canvas decking.  Some jobs call for a layer of roofing paper between the wood and canvas, and it is common to lay the canvas upon a thick coating of paint of marine glue.  The strips ("cloths") of canvas are lapped at the seams about 2", and the fastening may consist of brass or copper tacks spaced on 3/8" centers and kept about 3/16" from the edge of the material. Three or more coats of paint may be applied to the exposed surface of the canvas.
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A section of the canvas covered decks of a New York City ferryboat is shown in Figure 8. Hand rails of two types, as A and B are secured to the deck stanchions.  The latter may be of pipe, as shown, so as to serve the added purpose as drain spouts, the lower end terminating in a bridge foot.  This foot rests upon a lead plate, and bolts extend through the deck and the purlin.

Various gadgets and procedures are used in laying canvas decking, the object being to stretch the cloth as tightly possible.  Two contrivances are shown in Figure 9, and their simple details are fully shown in the sketches. On small craft, a skintight canvas may be obtained by coating the tacked material with a smelly and volatile preparation commonly known as "airplane dope"
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