Those days spent aboard your boat are rarely "lazy days" and they are never wasted days. They can be broiling hot days, though, if your cockpit or back deck doesn't offer the shade of a roof or a canopy. If you decide you want to add a canopy to your boat, but find the cost of a professionally-made canopy is more than you want to pay, you can do what those who work on exposed back deck of research vessels have done for years: make your own.
Use masking tape to outline the area you want to cover with the canopy. Make the corners as square as possible, using a carpenter's square, when you are laying the tape. Measure the area's length and width. Add 6 inches to the length and width to determine how much canvas you'll need.
Use one length of 1-inch PVC pipe--the vertical supports--for each 4 feet of each side and each end. Add both lengths and both widths of the canopy to determine its perimeter. Divide by four to calculate the number of vertical supports needed.
Drill two holes, each 3/4 inch in diameter, through the tape, at the each of the corners of the taped area. Mix enough marine epoxy to fill theses holes, and fill these holes with marine epoxy. Use the dry-erase marker to draw a 1 foot long line from the centre of these holes toward the centre line of the boat. Allow the epoxy to cure completely.
Use the jigsaw to cut a 3 3/4 inch long piece of the dimensional 4-by-4. Drill two 3/8-inch pilot holes, 2 inches apart, on the same side of the cube where you drilled the larger hole. Paint the redwood cube yellow and allow the paint to dry completely. Repeat at least three times, one for each corner.
Cut the 1-inch PVC pipe that that forms the vertical supports to the desired length. Cut the 1-inch PVC pipe that will form the upper frame into lengths of 3 feet, 11 inches.
Clean the inside of the bottom leg of one of the 1-inch PVC "T" fittings with a rag and acetone. Clean one end of a 1-inch vertical support with acetone. Apply cement to the inside of the fitting, push the vertical support into the fitting. Twist the vertical support a quarter turn to secure the joint. Repeat for all vertical supports.
Lay marine epoxy adhesive sealant on the bottom of the mounting cubes and on the deck where the mounting cubes will be located. Set each redwood cube on the centre of the tape and align the pilot holes with the dry erase markers on the deck. Screw the 4-inch screws through the cube and into the deck. Some epoxy will squeeze from beneath the mounting cubes, onto the tape. Repeat as necessary, until there are mounting cubes every 4 feet along the perimeter of the canopy. Insert vertical supports in the mounting cubes. Screw a 2-inch #14 screw into the side of the mount to secure the vertical support.
Apply glue to the horizontal parts of the "T" fittings, insert the 3-foot, 11-inch horizontal frame members and secure them with a twist. Each horizontal member will fit into two "T" fittings.
Fold 3 1/2 inches of the canvas under, attach female snaps every foot to the edge of the canvas and attach male snaps every foot, 3 1/2 inches from the edge. Fold the canvas over the upper frame and snap in place.
One time saver: mark the 4-by-4 into 3 3/4-inch segments, then drill the mounting and pilot holes in all the segments before you cut them into individual sections.
This work involves power tools. Appropriate cautions are advised.