Estep: How Wooden Ships are Built, 1928.

p 13:
For fastenings, dowels, treenails, drift bolts, spikes and screw bolts are employed. The various pieces may also be scarfed, that is, beveled together, so as to add to the strength of the joint.
Treenails are usually 1 ¼ inches in diameter and from 26 to 30 inches long. They are made from hard wood, usually locust, and are used chiefly for fastening the planking and ceiling to the frames. For this purpose a hole the scant diameter of the treenail is bored in the members to be fastened and the treenail is driven home with an air hammer. After it is in place, it is cut off, split on the end, and wedged to a tight fit. The subsequent action of the water is supposed to swell the treenail and make it fit tighter.
Although treenails are used extensively in modern shipbuilding, there is doubt as to their efficiency after the ship has had an opportunity to work in a seaway. Undoubtedly, however, they were employed in the construction of the ark, for want of knowledge of more modern fastenings, and this is a sufficient recommendation for their continued use in the eyes of many oldline shipbuilders. The chief virtue of treenails seems to lie in the fact that they work with the ship, and therefore do not present as unyielding a resistance as a steel fastening.
To supplement treenails, however, in fastening the main members of wooden ships together, steel or iron drift-bolts are used. Usually they are about 1-inch in diameter. They are generally driven by air hammer in holes bored 1/16-inch smaller in diameter than the bolt. Although the difference between the size of the hole and that of the bolt is small, they hold tenaciously, especially when the ship is new. It is said that drift-bolts driven 3 feet into fir timber hold so fast that they break in tension before they pull out. Wherever possible such bolts are driven through and clenched on steel rings in the inside.
For "sticking" the planking to the frames and other preliminary fastenings, as well as for securing the deck planks, galvanized standard ship spikes are used. Usually they are ½-inch square and 8 to 10 inches long. Screw bolts also are used for some forms of fastenings, as well as bolts fitted with washers and nuts. The latter may be taken up from time to time as required.

Test of Spikes

Some tests of spikes were made at the Seattle testing laboratory of the United States forest service recently, from which the following conclusions were drawn:

The form of the point of the common spike is such that it inclines not to follow the hole.
If the holes are not too large and the spikes follow the holes closely, the resistance to withdrawal usually will be increased.
If spikes do not follow the holes, the resistance to withdrawal may be greatly reduced.
Spikes driven close to the holes, but not into them, will have their resistance lowered.

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Putting on the Plank

The necessary holes for the fastenings are bored in the plank before it is brought out to the ship. After being lifted into place, the plank is tightened into position by means of chains, shores and wedges in the manner shown in Fig. 136. Before the plank is clamped in the place, the bottoms of the holes which are to receive the spikes are reamed out with a hand auger so the spikes may be set easily. The plank is first tacked or struck in position with 10-inch galvanized boat spikes which are driven by hand. Two spikes are driven at the ends and one in between on every frame. After these spikes are driven, the shores and wedges may be removed. The ring bolts also can be taken out, leaving the planking as it appears in Fig. 134. It is now ready to receive the final fastenings which usually consist of locust treenails and iron drift-bolts. The treenails, which are about 26 inches long and 1¼ inches in diameter, are driven into holes bored a scant 1¼ inches. After they are driven home, they are wedged on the ends and in some cases caulked. Special care is required in driving treenails in order to avoid crippling them, as in this case it is impossible to drive them any further and they must either be driven or bored out and their places supplied by others which generally are less efficient than if driven through in the first place. Treenails should be of well-seasoned sound locust or oak cut with the grain.

H. Cole Estep: How Wooden Ships are Built, Cleveland, 1928.

Transcribed by Lars Bruzelius

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