If you have an existing dock, adding a cantilevered hammock can be a quick and easy way to increase the relaxation areas without taking up deck space.
Start with a layout. Existing posts on a 6-8' center are ideal for this setup. In our case, we chose an L-shaped layout with two 4'x8' hammock areas. We also chose to install the hammocks 18" above the deck to make it easier to get in while not creating a fall hazard.
Next cut two 2x8's per hammock panel to 4' and angle cut the outer ends to 5.5". Drill two 5/8" holes 4" apart on the inner end and mount to the posts with 5/8" carriage bolts, washers, and nuts. Using the post and the horizontal 2x8's as a guide, mark and cut 22" gussets from another 2x8. Mount the gusset to the post with a 5/8" carriage bolt.
Using a wood clamp, secure the gusset to the horizontal 2x8 and drill two 5/16" holes approximately 8" apart using a long drill bit. Next, pass the 1/4" threaded rod through each hole, install a washer and cap nut on one end, and trim the other end to 1/4" long with the reciprocating saw. Finally, install a washer and cap nut on this end, making sure it tightens the horizontal and gusset 2x8's together.
Because we were also framing a new roof, we extended a hip beam out to help support the corner of the hammock framing. A 1/4" coated cable and clamps were used between the two. If you don't have a similar condition, install a diagonal gusset from the far corner back to the deck posts.
Install the hammock panels by clipping the outside rope through a spring loaded carabiner the clip that to the screw eye hooks. Be sure to pull the panels tight as they will stretch slightly over time.