Page 134 - British Inquiry into Loss of RMS Titanic Day 23 - 26

scantlings, but a standard of strength. 24323. How do you test your standard of strength - how do you arrive at your standard of strength apart from the question of scantlings? - We do this. We get from the builders the drawings of the vessel. One of these drawings is a midship section. That midship section is a section as if you cut the ship right through the middle. It shows the thickness of all the plates, the longitudinal members of the ship - for example, the thickness and width of all the plates forming the skin of the ship and the deck of the ship. 24324. But those are the scantlings, are they not? - Those are the scantlings of the ship. We then make an estimate of what the stress on the gunwale of that ship in tons per square inch will be, on the assumption that the vessel is subjected to a bending moment equal to the whole displacement of the ship, in this case about 52,000 tons multiplied by one-thirtieth of the vessel’s length. In that way we get at a certain figure of so many tons per square inch on the shear strake. We then, if I may so say, design another vessel, that is to say, we draw a midship section of a vessel having the scantlings of Lloyd’s Rules. But it necessarily is a much smaller vessel, because Lloyd’s Rules have no scantlings for vessels 850 feet long. We treat this smaller vessel in precisely the same way as we treated the “Titanic,” the large vessel; that is to say, we draw her midship section and we get the thickness of her plates, and we find out what the stress in tons per square inch on the gunwale is on precisely the same assumption - that is, that the bending moment is equal to the whole displacement of that ship when laden as prescribed by the Freeboard Tables, multiplied by one-thirtieth of the vessel’s length. We then compare those two figures. 24325. Now, we will go back to my two questions. First of all, have you any means of testing the strength of the ship apart from the scantlings? - I do not quite understand that question. 24326. You spoke of these tests: they are purely theoretical tests, are they not? - Yes. 24327. They are based upon the measurements; that is to say, “scantlings” is only the technical term for measurements? - Thickness of material. 24328. What I want to put to you is this: Have you any other means of testing the strength of the ship except by reference to her measurements? - No. 24329. Have you in that Table to which you refer any measurements for a ship above 26,000 tons? - No. 24330. If you have no measurements for a ship above 26,000 tons, and if you have no means of testing the strength of a ship except by reference to her measurements, how do you test, and how, in fact, did you test, the strength of the “Titanic,” which was a ship of 45,000 tons? - In the manner which I have described to you, Sir. 24331. But where do you get your starting figures from? - My starting figures? 24332. For the purpose of making your calculations to which you refer? - From Lloyd’s Rules. 24333. Are there any of Lloyd’s Rules which, in fact, give you particulars for any ship of this size, or anything like the size of the “Titanic”? - No. May I add one word of explanation? The whole thing is based upon this assumption, that the tendency to bend the ship will be in proportion to the displacement, that is, the total weight of the ship and her length will be a certain definite proportion of the total displacement - the weight of the ship and her length. If that is not true, then some fault may be found in the method, but you will see that by basing it on the total weight of the ship we do take account of the size of the ship. 24334. In taking account of the size of the ship, do you take account of the detailed measurements in every part of the ship? - In every material part of the ship. 24335. Was that done in the case of the “Titanic”? - Yes, so far as my judgment goes. 24336. I am not talking about your judgment. I am on a question of fact, Mr. Archer. Was that done by the Marine Department of the Board of Trade in the case of the “Titanic”? - May I ask you to repeat the question; perhaps I have not exactly followed you. 24337. You say that you arrive at the bendability of the ship by reference to her breadth and depth and length? - No, Sir, I did not mention breadth and depth at all. 24338. Length and weight? - Yes.