2. The policy of commerce, and the various complicated rights which different persons may have in the same thing, require that not only those who have an absolute property in ships or goods, but those also who, have a qualified property in them, may be at liberty to insure them. For example, when a ship is mortgaged, and the mortgage has become absolute, the owner of the legal estate has an insurable interest, and the mortgagor, on account of his equity, has also an insurable interest. 1 Burr. 489. See 20 Pick. 259; 1 Pet. 163.