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Deck your jon boat to provide an area to mount a fish-fighting chair and get a higher vantage point for fishing. Decking is usually done in three parts: forward, stern and middle. Typically, the middle deck is lower. Reinforce your deck with fiberglass-taped, wooden braces. Sealing the wood prevents warping. Use stainless steel screws to prevent rust in a marine environment. For the finish, diamond plate is suitable to prevent anchor chafe and looks good, but any kind of industrial flooring will work.
Items you will need
Carpenter's pencil or marker
8 2-inch-by-2-inch hardwood boards (at least the length of the boat; add one more if the boat is over twelve feet in length)
Circular saw (hand held)
Marine adhesive sealant
Drill motor and drill bits
Screw-gun or screwdriver
8 Stainless steel pan head screws
Marine plywood, 1 sheet, 4 by 8 foot, 1/2 inch
25-50 pounds of weights
Jig saw (hand held)
Polyester fiberglass resin (1 gal.) and hardener
50 feet of 4-inch-wide, 9-ounce fiberglass tape
Razor knife or heavy scissors
Acetone (1 qt.)
Clean, dry rags
1 2-inch-by-4-inch hardwood board (at least the height of the boat)
Industrial flooring or diamond plate, 12 feet by 12 feet
Indoor-outdoor or marine carpet
Design the Deck
Locate where storage areas, the live-bait well and the beverage cooler will be located.
Measure the length of the gunwales from the transom to the prow.
Measure the length of the transom and the prow.
Locate where the anchor and anchor rope will touch the deck.
Determine how long the fore deck, aft deck and middle deck will be.
Make the Gunwale, Transom and Prow Braces
Mark three 2-inch-by-2-inch boards at the inside length of the gunwales and use the circular saw to cut them to size.
Paint the cut boards with wood sealer and set aside to dry.
Mark one 2-inch-by-2-inch board to the width of the transom, minus the width of the two gunwale braces and use the circular saw to cut it to size.
Mark one 2-inch-by-2-inch board to the width of the prow minus the width of the two gunwale braces and use the circular saw to cut it to size.
Paint the cut boards with wood sealer and set aside to dry.
Attach the Gunwale, Transom and Prow Braces
Apply marine adhesive sealant to the first 3 feet of one of the gunwale braces.
Clamp the first 3 feet of the gunwale brace into position, beginning at the bow, inside the boat, using the four C-clamps.
Drill pilot holes through the boat hull into the gunwale brace every 4 inches. If a clamp is in the way, move it slightly and re-tighten it before drilling.
Working from the bow, install screws through the hull into the gunwale braces. Release the C-clamps.
Apply marine adhesive sealant to the next 3 feet of gunwale brace and clamp in place. Install screws as before.
Repeat the process of moving the clamps, applying the marine adhesive sealant and driving screws until the entire gunwale brace is installed.
Make the Deck
Use your circular saw to cut the plywood to a length equal to the length from the bow to the end of the fore deck. This is where your fishing chair mounts, so leave enough room for your feet in all directions.
Lay the cut plywood on the front of the jon boat so that it is even with the prow and square to the sides. Weight it down so that it will not move.
Draw a marker line on the plywood, tracing the hull line on both sides of the hull. Mark the gunwale braces where the fore deck ends.
Turn the fore deck over and use the jig saw to cut off any edges that extend outside of the boat.
Attach 2-inch-by-2-inch bracing boards perpendicular to the keel on the down side of the deck. Be sure the bracing boards are cut slightly shorter than the deck's width so they don't stick outside of the hull. Cut as many bracing boards as you need to space them 12 inches apart under the deck, with the first one 12 inches back from the prow. Attach the bracing boards to the underside of the deck with resin and hardener brushed onto fiberglass tape, cut to fit with the razor knife or scissors. Tamp the fiberglass down firmly with the fiberglass roller. Use the acetone for clean up.
Paint the fore deck with wood sealer and set aside to dry.
Clean the area of the gunwale braces where the hull is to attach with a dry rag.
Apply marine adhesive sealant to both gunwales and the prow, from the bow to where you marked the aft end of the fore deck.
Turn the fore deck right-side-up. Lay it over the prow and forward parts of the gunwales. Jiggle it into position and weight it down so it does not move.
Attach the fore deck to the gunwale and prow braces by drilling pilot holes and driving screws down through the fore deck into the braces.
Make a deck brace out of a 2-inch-by-2-inch board and install it amidships on the edge of the aft part of the fore deck. You can eliminate this step if one of the fiberglassed braces was located exactly at the aft edge of the fore deck.
Make a 2-inch-by-4-inch brace from the under side of the deck to the keel. Install with marine adhesive sealant at the aft end of the fore deck.
Repeat this process to make and install the aft and middle decks.
Finishing the Deck
Cut industrial flooring or diamond plate to fit the area where the anchor is used. Install it with marine adhesive sealant.
Cut holes in the deck for the beverage cooler, live-bait well and storage locker. Drop in the units or install a permanent storage hatch with screws and marine adhesive sealant.
Install boat chair(s) according to the manufacturer's instructions.
Cut indoor-outdoor or marine carpeting to fit the deck. Install the carpeting with marine adhesive sealant. Weight the carpet to keep it in place until the adhesive dries.
- Acetone is volatile, evaporating very quickly, leaving a potentially explosive gas behind. Keep acetone away from flames and use plenty of ventilation.
- The middle deck can be installed a few inches lower than the fore and after decks. To do this, cut the gunwale braces to fit, and install at the desired depth.
- Examine the deck for any "oil-canning" movement, particularly under the chair. Should this occur, cut a 2-inch-by-4-inch wooden brace and install under the deck downward to the hull with marine adhesive sealant, directly under the chair.
- The gunwale braces can be reinforced by running resin-impregnated, fiberglass tape underneath. Put hardener into the resin, mix and apply it to the fiberglass with a paintbrush. Use a fiberglass roller over the installed fiberglass while it is still wet to get the best adhesion.
- Exterior-grade plywood can be used instead of marine grade.
- If your boat is longer than 8 feet in length you will need an additional sheet of plywood. If it is longer than 16 feet, you will need a third sheet.
- "Boatbuilding and Repairing With Fiberglass"; Melvin D.C. Willis; 1972
- "Improve Your Own Boat"; Ian Nicolson; 1985
- Youtube; Modified Jon Boat; F4FPhantomII; March 2009
- Creatas Images/Creatas/Getty Images