Kitchen utensil the turn of the 20th century, Maria Parloa noted that kitchen utensils were made of (tinned or enamelled) iron and steel, copper, nickel, silver, tin, clay, earthenware, and aluminium. The latter, aluminium, became a popular material for kitchen utensils in the 20th century. Copper has good thermal conductivity and copper utensils are both durable and attractive in appearance. However, they are also comparatively heavier than utensils made of other materials, require scrupulous cleaning to remove poisonous tarnish compounds, and are not suitable for acidic foods. Copper pots are lined with tin to prevent discoloration or altering the taste of food.
Bruce foil changes in wind speed or direction can unbalance the foil and cause heeling. In addition, a foil on the windward side presents an unstable situation, since any lifting of the foil out of the water, by mechanisms such as heeling or wave action, will result in reduced downwards force, potentially leading to capsize. A lee foil provides more stability, as loss of lift will force the foil back into the water. The main advantages over a typical centerboard or leeboard is that the Bruce foil allows the sails to remain nearly upright and keep the full force of the wind