Structure for marine vessel

A method of constructing a vessel comprising a body portion, at least one left hull, at least one right hull, and a chassis module comprising a frame, at least one left locating linkage arrangement for connection to the at least one left hull and at least one right locating linkage arrangement for connection to the at least one right hull, each locating linkage arrangement permitting at least heave motions of the respective hull relative to the frame and constraining the respective hull in at least lateral, longitudinal, roll and yaw directions relative to the frame, when the respective hull is connected to the respective locating linkage arrangement, each locating linkage arrangement including at least one member, each member having at least one respective movable first joint adjacent a first end and having at least one respective movable second joint adjacent a second end, each movable second joint being connected to the respective hull when the respective hull is connected to the respective locating linkage arrangement, the frame including respective attachment points for at least one of the movable first joints of each locating linkage arrangement, the frame including respective support frame mounts for at least one left support and at least one right support, the frame including attachment points of a body of the vessel;

• the frame including a forward portion, a rearward portion, and a spine portion between the forward and rearward portions;
• wherein solely the spine portion connects the forward portion and the rearward portion;
• wherein the frame is configured such that more than half of any static loads between the locating linkage arrangements and the hulls or between the supports and the hulls, are resolved within the frame;
• wherein a lateral distance between a hull joint of a left locating linkage arrangement and a hull joint of a right locating linkage arrangement is a track width, the frame having a length, the spine portion defining spine dimensions comprising a spine length, a spine height, and a spine width;
• wherein the spine dimensions include at least one of the following:
• the spine length being at least one quarter of the length of the frame;
• the spine height being less than one tenth of the length of the frame;
• and the spine width being less than one third of the track width;
• and
• the spine housing at least part of at least one of a power system, a control system of the chassis module, and components of the chassis module, the method comprising:
• assembling the frame and locating linkage arrangements of the chassis module.