Abstract: An arrangement for minimizing the pressure differential across shaft seals is characterized by a pump powered by the rotative force of a shaft to pump a fluid from a reservoir chamber into a chamber next-adjacent to each shaft seal. When the pressures in the chambers adjacent to the seals exceed a predetermined magnitude, a pressure relief arrangement is opened, thus venting the chambers and maintaining the differentials across the seals as minimal as possible.

Abstract: Apparatus for protecting subsea structures, and in particular christmas trees from damage by fishing nets, trawl boards, anchors and other marine equipment, include a protective structure which is placed over the christmas tree. The protective structure has an opening in the top portion to allow access to the christmas tree when such access is needed and a protective cap which closes the opening to prevent damage from silt, sand, trash and overhead falling objects. The entire protective structure is secured in place by one or more piles which are driven into the sea floor or by cementing one or more steel piles in place in the sea floor. The protective structure and the cap are guided into place around the well by guide cables attached to the guide base of the well. A lifting device in the protective cap facilitates removal of the cap by a single cable.