RECENT observations in the Dry-Docks of New-York have convenced us that a few remarks on the above subject will not be ill-timed. We are surprised that shipbuilders are not more careful of their reputation than a few of them appear to be, who suffer the tree-nailing of their ships to be but half done. The re-treenailing of a new ship upon a dry dock affords one of the most unsightly, and we may add, shameful, exhibitions of mechanical depravity known "along shore". Hundreds of passers-by inquire, "Who built this ship?" — "Where does she belong?" We have heard the answers in a recent case of this kind — "She was pegged together down-east" — "Belongs to Boston". "The owner says he built her for his own son. We wonder what kind of work he would put off upon a stranger!" It is exhibitions like this that blackens the character of shipping from quarters where we know there are as good ships built as ever sailed.
The ship alluded to was re-treenailed in consequence of discovering that the work was so badly done that three treenails out of four in a frame were driven only three or four inches into the timbers. This was found to be the case in cutting out a short piece of plank for repairs. The surveyors decided that the new copper must be stripped off, and all the treenails (which were of inferior quality) be backed or bored out, and locust driven in their places. This was done at underwriters' expense, tha ship having been on shore with full cargo on board. The pumps which may be heard working at unseasonable hours, in port, often tell tales of defective tree-nailing which should make builders blush. Job work and low prices have led to dishonest workmanship, and these, again, have re-acted upon prices until the fastening off of ships has become entrusted to irresponsible men in many yards, who are not well looked after by the foreman, chiefly for the reason that "it don't pay to be so particular".
The tree-nailing of a ship is a part of the work which is just as important as any, while it is notorious that it is now most likely of any to be slighted. Owners and underwriters would do well to consider the difference between pegging thick plank to the timbers, and tree-nailing them quite through, and wedging on both ends. Bad work is done in the following manner: The ceiling being worked before the planking, and square fastened, there is necessarily a breat number of "iron" or short holes made in the latter, going little or no distance into the timber; many of these are sometimes purposely made by the hole-borer — some being only sham "iron holes" at that. These hole-borers are generally paid by the score, in number, and before crank augers came into fashion they done better work — now they figure for a "fortune" on every job. The tree-nails shaver comes next. He likes to buy his own stock, and finds it cheaper to fit small ones (in the rough state) than those having size enough to fill the holes — having only to take the corners off. He fits them badly — either tapering from head to point, or shaving them slack in the middle of their length, thus giving them drift only at the ends, whereby they hold nothing, comparatively. The head is made of extra drift, and in driving up, the plank is frequently checked, while the hole is not filled for half its length. Treenails that are the worst driven check the plank most. A boy need not work long on the stages to discover that a treenail of such large drift as to check the plank on entering cannot be driven quite up to the mark; it is the last two or three blows that do the mischief, and lead the uninformed to think that the work is only a little "extra well done". Treenail rents, like those from bolts, are the most difficult to make tight — especially so in soft covering.
BUt there is still another source of defective workmanship. The treenail drivers — often the most worthless men in the yards, even if the hole be through bored, and the treenails well fitted — sometimes slight their portion of the work. In dry-docks cases are met with where the holes are through, and the tree-nails well fitted, but only driven a few inches into the timber. We do not approve of round tree-nails. The best form for every purpose is eight-square, whether hand or machine made.
We will now indicate how holes should be bored, and treenails be prepared and driven. However simple these operations may be supposed to be, we are pursuaded there are some persons connected with them who have something to learn respecting the same.
It is said that a certain builder abroad taunted a New-Yorker, saying: "You don't know how to drive tree-nails in New-York!" — "they go slack half the way!" "Indeed," replies the other, "they may have been two-drift tree-nails which you saw driven in New-York — that is one point of their excellence". "A two drift tree-nail!" rejoins the first party; "what new humbug is that?" "Neither "new" nor a "humbug". Have you grown grey amongst the chips of a shipyard, and not learned that long tree-nails could be best driven with two drifts instead of one — the hole being bored with two augers, of different sizes, instead of one?" "I never heard of it before":
Mr. Isaac Webb, well-known in past time as one of the leading ship-builders of New-York, was the first to test the merits of this invention. Tree-nails of this pattern can be driven 1/32 to 1/16 inch larger than any others in the same sized hole. They fill the hole from end to end when driven, although they necessarily enter it slackly at first. They hold better, and cost less for driving, and what is most important, seldom check the plank. Ships properly tree-nailed in this manner turn out creditable to builders, profitable to owners, and popular with underwriters.
Within two or three years steam machinery has been perfected for manufacturing tree-nails on the two drift principle, and several of the shipbuilders of New-York prefer them to any other. Wm. H. Webb has used them exclusively for more than two years, and other builders for two-thirds of that time. The works are at Jersey City, N.J., where tree-nails of all sizes and lengths are made from the best locuts grown in the country. The patent is Fitzgeralds', and it is calculated to confer immense benefits upon the tree-nailing of ships, by producing a superior article for least cost. Abm. Hoagland is proprietor of the Jersey City Tree-nail Factory, to whom orders should be addressed. The operation of eight-squaring and fitting the square nail tree-nail is performed with cross-cutting rotary knives, which take off the corners and leave the sides of the tree-nail slightly concave, and roughened, thus very materially increasing the friction, and ensuring the utmost holding power. It is almost impossible to drift out one of these tree-nails when properly driven. Augers are made for them which hold their size until worn out, so that it is not necessary to alter the gauge of the machine to suit the wear of the auger as formerly. Faithfullness in workmanship might be restored at no increase of cost by using tree-nails such as we have described. Inspectors, look sharply after the tree-nails, and see that they are not driven from both inside and out in the same holes, and that they do not check the plank, and are properly wedged on both ends.
Transcribed by Lars Bruzelius
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