Kayak racks come in all shapes and sizes. You can build a wooden kayak storage rack using basic power tools and elementary carpentry skills. Its flat design allows you to lay kayaks on the rack at an angle to one another; stacking more kayaks in the same space. The design makes it easy to load and unload boats and it takes very little time to build.
Dig two post holes 3 m (10 feet) apart. Dig a second pair of post holes 3 m (10 feet) apart parallel to and 1.5 m (5 feet) from the first pair. Dig the holes 60 cm (2 feet) deep, wider at the bottom than at the top. Do this by angling your post hole digger as you strike so that the cutting edge widens the bottom of the hole without cutting away at the sides. This produces a more stable base for the posts.
Saw the posts into 1.2 m (4 foot) lengths if they aren't already that length. Place them in the holes and lay the two 3.6 m (12 foot) 5 by 30 cm (2 by 12 inch) boards temporarily on top of the pairs of posts. Use the spirit level and the boards to level the posts by adding dirt under the posts or digging the holes deeper. If the ground itself is level, the tops of the posts should be level at 60 cm (2 feet) above the surface. You can level the pairs of posts with each other, if you want, but unless the ground is very steep, it doesn't matter much if the boats aren't perfectly level when resting on the cross members. If you do level the post pairs, start with the lower pair and raise the posts a few inches, then level the pair that are higher on the slope.
Mix two bags of concrete in a wheelbarrow for each hole. Pour the concrete mix into each hole, making sure the posts remain vertical. Allow the posts to set and cure overnight.
Drill 9 mm (3/8 inch) pilot holes one foot from each end of the 5 by 30 cm (2 by 12 inch) boards in the centre of the boards after checking again to make sure that the 3 m (10 foot) distance between these pilot holes will match the centre-to-centre distance between the post pairs. Drill matching pilot holes in the posts so that the top edges of the 5 by 30 cm (2 by 12 inch) boards will be level with the tops of the posts on the long side, and lag screw the 5 by 30 cm (2 by 12 inch) boards to the sides of the post pairs on the side facing away from the opposite pair of posts.
Cut two 6 m (20 foot) lengths of fire hose. You may be able to obtain old fire hose by contacting your local fire brigade about purchasing some retired fire hoses. Screw one end of a 6 m (20 foot) fire hose to the end of a 5 by 30 cm (2 by 12 inch) board using a galvanised screw and washer. The hose should lie flat along the top edge of the board. Push up an 20 cm (8 inch) segment of hose to make a bump, and drive another screw and washer through the hose. Continue making a series of bumps in the hose with a screw between each bump. Make them about the same size, working along the cross member until you reach the end. Trim off the excess hose. This row of canvas bumps will help protect the hulls of your boats from bumping when they rest on the rack. Repeat with the other cross member and hose. Though not as effective a solution, if you can't obtain fire hose you can wrap strips of carpet over the tops of the boards.
Space seven eye screws approximately 60 cm (2 feet) apart, evenly spaced across the outside front of each cross member. These will provide tie-down points for the boats on the rack. Don't worry about the eye screws' positions relative to the canvas bumps on top.
Always tie down kayaks or canoes on any outdoor rack to prevent winds from lifting them off the rack and damaging them. Use pressure-treated timber for the cross members and you won't have to varnish or paint the wood. Untreated wood should be painted or varnished to prevent rotting. The posts will be treated and don't need painting.