Complex sentence: Because of delays in the manufacture of these weapons the completion of "Anson", and of all of her sisters, was vastly prolonged, there being some six or seven years between laying-down and commissioning.
Split into simpler sentences: Because of delays in the manufacture of these weapons the completion of "Anson", and of all of her sisters, was vastly prolonged. Delays spanned six or seven years between laying-down and commissioning.