Abstract: An apparatus for loading a topside onto a jacket is provided. The apparatus may include: a projecting structure extending beyond a deck of a marine vessel wherein the projecting structure configured to support the topside and the projecting structure is dimensioned sufficiently long enough to allow the marine vessel to approach a submerged jacket and position the topside above the submerged jacket without having the marine vessel contact the jacket; and a support configured to support the topside above the projecting structure. A method for one of installing and removing a topside from a jacket may be provided. The method may include: positioning sponsons attached to a marine vessel around a jacket; supporting at least part of the weight of the topside on the sponsons; and one of attaching and detaching the topside and jacket.