How To Build a Docking System for a Boat

A docking system for a boat is comprised of a floating platform, docking bumpers or cushions and special mooring anchors to hold the dock in place. If the dock is to be installed in an ocean waterway, cove or bay the anchoring system must be able to adjust with the tide. This will ensure the mooring anchors do not pull lose with a rising tide.

The platform will be set on large blocks of commercial Styrofoam floats and it must be constructed so it is sturdy enough to support people and also to maintain the craft within the slip area. The inside edges of the slip will be lined or cushioned to prevent damage to the hull during docking or in heavy weather.

The dock will be fabricated and assembled on dry land and then transported to the docking area.

A standard dock for small craft is approximately 20’ in overall length and 12’ wide with the slip area approximately 16’ long and a minimum of 8’ wide. The head of the slip forms a “V” pattern and the foot of the slip is open to water.

  1. Begin by placing (5) pieces of commercial grade Styrofoam, each 20” wide, 16” thick and 8’ long in a u-shaped configuration. Butt (2) of the side pieces end to end and attach them together by implanting a ¾” thick x 3-1/2” wide pieces of moisture treated lumber on the top surface and fasten with 6” wood screws. Repeat this with the (2) opposite side pieces.
  2. Next, butt (2) additional pieces of Styrofoam and lay them perpendicular to the side sections across the head of the u shape. Size these pieces so that the overall length is the total width of the dock or 12’. Attach them together, butt to butt in the same manner as the sides. Now attach this head piece to the sides using ¾” x 3-1/2” treated wood in the same manner. We now have a u-shaped Styrofoam under-frame.
  3. Measure and cut (3) pieces of moisture treated 2” x 12” Doug fir to match the side and head dimensions of the under-frame. Lay them up as an outside frame work, flush with the top of the Styrofoam and extending down 12”. Attach these to the foam with 6” wood screws. Repeat this process using 2” x 12” lumber and lay up a similar frame for the inside the slip area. Finally, cut similar pieces to fit across the short ends of each side piece and attach them in the same manner. We now have a framed platform with exposed Styrofoam on the top surface.
  4. Turn the dock over so the entire bottom is accessible. Measure and cut (4) 2” x 6” pieces to fit across the sides near the head and foot of the dock. Pre-drill a 5/8” hole at the center of each piece and affix a ½” diameter eye bolt with a 2” eye through each piece. These will be the tie points for the anchoring system lines. Attach the underside pieces with 3/8” x 6” galvanized lag bolts with washers, (2) at each end of each piece. Turn the dock over to a face up, flat position.
  5. Using 2” x 6’ moisture treated Doug fir begin laying the dock platform atop the under frame by attaching sized pieces to the 2” x 12” with 6” screws. At the head of the slip, span these pieces out, over the open area in a way that forms a “V” to receive the nose of the boat. Be sure to leave a ¼” gap between all dock pieces for expansion.
  6. Countersink all wood-to-wood connections ½” deep and fill these with dowels cut flush to the surface of the wood.
  7. To line or cushion the slip, lay up 1” x 3-1/2’ moisture treated lumber, approximately ¼” below the dock surface at the inside of the slip and across the open ends. Attach with 3” wood screws.
  8. Line the slip with either heavy canvas as a split fire hose or a commercial grade resilient rubber lining. Attach at the top and underside of the 1” x 3-1/2” with wood screws. Do not install any screws that may contact the hull into the face of the lining. Finally, pre-drill and install (4) 8’ long dock cleats at the outside corners of the slip area. These will serve to accommodate dock lines.

With regard to the mooring system, most often lakes or protected bays have stranded steel cables in place at the shallow bottom areas where docks will reside. These cables are strung perpendicular to the direction of the dock, or parallel to the shoreline. Docks are moored in place with lines that extend down from the eye bolts and affix to the cables.

It is advisable to consult a management agency or other monitoring agency for recommendations regarding mooring and anchoring a boat dock. Once these matters are clarified, the dock may be transported and placed with the aid of a hydraulic crane.


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