Transactions of the Royal Institution of Naval Architects Volume 13 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1872 Excerpt: ... and cut off from every piece of metal which comes through the bottom of the ship. It is an extremely difficult thing to keep the insulation perfect when the sheathing has to be fastened with nails, which may happen to come in contact with the bolts of the sheathing itself; but referring to the diagram which Mr. Mallet has exhibited, so far as the ends of the ship are concerned, the copper line should not have been brought into contact with the brass stem or stern-post, because it is insulated and there is no such connection. But there is a more important question, which is this: --Are we liable to danger when there is salt-water in the inside of the ship, there being salt-water on the outside? Does the copper on the outside of the ship cause galvanic action on the inside of the iron plating? We are quite prepared to say that there is risk of damage to the outside of the iron plates of the ship from the copper on the outside, if the insulating coating on the iron gets destroyed, and if the water gets into the place where the insulating material has been removed; but we are not prepared to admit that galvanic action will take place on the inside of the ship, inasmuch as the water on the inside of an iron ship is in a different vessel and is cut off from the water on the outside of the ship. I think Mr. Mallet will have to prove to us that if he put into one vessel a piece of copper, and into another vessel, having another fluid a piece of iron, and puts a wire between the two, galvanic action will take place. My opinion is that it will not; and if that is so, we have not to apprehend the destruction of the inside of the ship, even supposing we get the salt water in there. The Chairman: There is more or less salt water which always gets in ships in some way or..