- The alloy nature of Stainless Steel and its thin, transparent layer on the surface provides a self
healing feature. When activated by oxygen within the air or water then it is this layer which
repairs lightly scratched or any damage to the surface.
- Stainless steels contain a significant amount of chromium, which forms Chromium Oxide
when it oxidizes (rusts).
- In contrast to a simple carbon steel, which forms iron oxide when it
rusts, (the flaky reddish brown oxide we typically associate with rust).
- Iron oxide is brittle and permeable, doing little to prevent further oxidation of the steel surface. In contrast, chromium oxide does not have an objectionable appearance, being the same effective color as the base metal, just a bit duller, and is hard and resilient.
- When you scratch or mar stainless, the
exposed chromium just forms a new oxide layer, protecting the underlying metal.
It is a two dimensional drawing of a three dimensional surface of the ship’s hull form. This plan is very useful for the following information:It is used for marking the location of a hull Damage on this plan by identifying the strake number , letter and frame number so that the exact location of the damage and also suggested repairs are marked in a localised copy. The shell expansion can be used for finding areas of painting surfaces such as topside, boot topping and bottom areas by applying Simpsons rules directly. In the shell expansion the vertical scale used is different from the horizontal scale and a suitable adjustment has to be made when calculating areas. This becomes useful in solving disputes concerning areas of preparation and painting. It gives information on the thickness of the original strake which is indicated by the number in the circle shown in the strake. The quality of steel used is also shown by letters A,B,D E and AH, BH,DH, EH.