These are the two small strut channels attaching the node to the long strut channel.

Before removing any parts, rotate the long strut channel (still attached to the node) so that it is no longer over the water.

Using a 1/2" adjustable or socket wrench, remove the four 1/2" hex head screws attaching the old node to the small strut channels.

Be sure to remove the nuts and washers on the inside of the small strut channels as well. (Total: Four 1/2" hex head screws, four 1/2" nuts, and four washers)