The following method of bolting a patch on a boiler perhaps shows some originality. It was required to patch the bottom of a combustion chamber of a very old boiler, badly pitted on the water side. Riveting was impossible for want of space. The patch was five feet by two, fitted on the fire side, and the greatest difficulty to overcome was to make the bolts watertight, owing to the impossibility of driving them or getting a contact under the heads against the bad plates, Gaskets did not appeal to the repairer, and a metallic contact was aimed at. This was accomplished by making each bolt act as an ordinary miter-seated valve. They were turned a hand-workable fit (all but the last 1/4 inch, which was tight) to reamed holes of steel, and case-hardened, fitted in from the water side, and hammered up with a spanner. The "seat" was sunk into the boiler plates. There were altogether 128 bolts in the patch. The job when finished passed a government inspector's examination, and steamed from Honolulu to San Francisco without mishap.

Fig. 157 - Bolting a patch on a boiler.