Three kinds of fastenings are used for securing outside planking of a vessel's frame. Wood treenails, through bolts with nuts and clinch bolts (bolts whose ends can be clinched or riveted over clinch rings or washers).
Number of planking fastenings should always be proportioned to width of strake of plank.
Planks above 11 inches must have at least two fastenings into each frame, called double fastening. Planks over 8 inches and up to 11 inches must habe alternate double and single fastenings; that is, have two fastenings in one frame and one fastening in adjacent one.
Planks under 8 inches in width can be single fastened; that is, have one fastening driven through each frame.
All butts of planks must be fastened with at least two bolts going through the timber on which butt is cut and one bolt through each adjacent timber. These butt bolts must be riveted or have nuts set up on washers.
Treenails used for fastening planking must be made of straight-grained well-seasoned hardwood (locust or other approved kind) and must be driven into holes that are sufficently small to insure the treenail having a maximum of holding strength. After treenails are driven their ends must be cut flush with outside of planking and inside of frame (or ceiling) and then wedged across grain with hardwood wedges.
When fastening planking it is very necessary to give propoer consideration to the relative positions of fastenings of outside planking, inside ceiling and of all knee and other fastenings that mus pass trough frame timbers, because if this is not done many fastenings may pass through a frame so colse to each other that wood of frame will be cut away and both strength of frame and holding power of fastenings reduced.
These rules should govern fastening of planking and ceiling:
(a) Not less than two-thirds of treenail fastenings should go through outside planking, frame and inside ceiling or clamps.
(b) At least one fastening in each frame should be of metal, clinched or riveted on inside of frame timber.
In a number of present-day wooden vessels defects in planking fastening are apparent, and these defects are in some cases so serious that the structural strength of vessel is much below requirements. Some of the more serious defects are due to
(a) The use of augers that are too large for fastening diameter.
(b) The use of an improper number and size of fastenings (usually too few and too small).
(c) The use of unseasoned planking material and improper spacing of fastenings.
(d) Improper location of butts and improper butt fastening.
(e) The omission of edge fastening, especially through garboards.
(f) Imperfect wedging of treenail fastenings.
(g) Failure to properly clinch, or rivet, metal fastenings of planking.
The augers used for plank fastenings should be sufficiently smaller than diameter of fastening to insure that fastening will require exceptionally hard blows to drive them. In my explanation of keel fastenings, I mentioned proper sizes of augers to use. The number of fastenings driven into each frame timber should not be less than mentioned in this paragraph and their diameters should never be less than given in table below:
| PLANKING FASTENINGS | ||
|---|---|---|
| Thickness of Planking | Diameter of Bolts | Diameter of Treenails |
| 1" | ½" | 7/8" |
| 2½" | 5/8" | 1" |
| 3-3½" | ¾" | 1 1/8" |
| 4-4½" | 7/8" | 1¼" |
| 5-5½" | 15/16" | 1 3/8" |
| 6" or over | 1" | 1½" |
All planking material shoudl be properly seasoned, because unless it is the natural shrinkage of wood during and aften construction will cause seams to open, caulking to loosen, and thus leaks will develop and strength of vessel be greatly reduced. It is folly to use "green" planking material. While air-drying is best, it is better to resort to smoke or steam-drying than to use unseasoned material and in fact if properly and carefully done smoke or steam-drying does not detract from strength and duration of planking material.
Butts should always be located according to rules mentioned in this chapter. Edge fastenings should always be used along garboards, at butts of sheer and along sheer strake.
Another method of fastening planking of vessel is when the plank is being put in place to use a sufficient number of spikes, "dump bolts," and treenails, to properly hold the planks in place and after the ceiling has been wrought to, complete the fastening by putting in the balance of treenails and all the through bolts. The first fastenings, to hold planks in place, go through planking and into frame timbers, and the second fastening through planking, frame timbers and ceiling. And still another, older method is to use a minimum number of spikes and some temporary fastenings (bolts with nuts) for the first fastenings, and when the ceiling is being put in place to withdraw the temporary fastenings, continue the boring of these fastenings holes through the ceiling, and then put in the permanent planking fastenings through planking, frame timbers and ceiling.
The principal things to bear in mind are:
(a) To consider the fastenings of ceiling and planking as being one and to so space the fastenings of both planking and ceiling that the maximum number will serve teh double purpose of securing both planking and ceiling to the frame timbers.
(b) To so space all fastenings that there will be a minimum number of holes bored through the frame timbers. If the frame timbers are weakened too much by having an excessive number of fastening holes bored through them, the frames will not properly hold the fastenings and are also liable to break under the strains that are put on them when a vessel works in a sea.
Space fastenings properly, bore the proper sized holes for every fastenings, drive and rivet or wedge each fastening properly, and use the proper number of fastenings and the vessel will have the maximum amount of strength. Figs. 46, 47 give illustrations of proper spacing methods for plank fastenings.
All planks are "spiled" in manner that garboard is, and as each plank is fitted in place it should be tightly weged agains the next plank before any fastening is driven. Of course all seams of planking must be perfectly tight inside, and open, for caulking, on ouside, and care should be taken to have upper edge of each plank follow the line laid our for it.
The last strake of planking to put in place is the shutter strake, so called because it "shuts" or closes the last space that planking has to fill. On Fig. 91 the shutter strake opening is clearly shown.
After planking is completed and fastenings all secured, planking is ready for roughing off caulking and smoothing, but this work should be delayed until the last moment in order to give planking to properly dry out.
Transcribed by Lars Bruzelius
Sjöhistoriska Samfundet | The Maritime History Virtual Archives | Shipbuilding | Fastenings.
Copyright © 1996 Lars Bruzelius.