Free trim relevance to offshore vessels?

Most types of offshore support vessels with short and high fo'c'sles and long after decks are designed to operate with a significant trim by the head, but this is not always practical for vessels engaged in anchor handling, witch requires hauling and deploying of anchor moorings and buoys over the stern. These operations usually must be carried out quickly, particularly when the tug is supporting a rig or a moving platform that is being controlled by hauling in on its moorings. Consequently, the tugs are usually operated with a slight stern trim, even though this increases their exposure to danger of rapidly losing stability through the "free trim effect". Furthermore, the weight of the tow or chain acting at the tugs stern roller increases the stern trim, mean draft and KG, all of which reduce the vessels reserve stability, so the stern trim must be kept to the minimum necessary for carrying out the anchor handling operation. The attached figure 1 illustrate the "Free Trim Effect"