How to Replace a Wood Transom on an Aluminum Jon Boat

How to Replace a Wood Transom on an Aluminum Jon Boat

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An aluminum jon boat with a wood transom that needs replacement means possibilities, such as making the transom taller to accommodate a long-shaft outboard. Whatever your choices, the end result needs to fit well, be properly finished and securely attached to the aluminum hull. Whether the wood transom on your aluminum jon boat is damaged or deteriorating, replacing it takes only some wood, the right tools, the right kind of caulk and paint or other surface sealant.

Items you will need

  • Adjustable wrenches

  • Right angle brackets, 1/2-inch bolt holes

  • Half-sheet, 3/4-inch marine plywood

  • Pencil

  • Power saw

  • Drill

  • 1/2-inch bit

  • Primer paint

  • Sealant

  • Disposable paint brush

  • Adhesive marine caulk

  • 1/2-inch bolts and nuts

  • Paint

Step 1

Remove the bolts holding the plywood to the right-angle brackets that hold transom to the sides and bottom of the boat, using two adjustable wrenches. Replace damaged brackets, if necessary, with brackets that can accommodate 1/2-inch bolts.

Step 2

Hold a half-sheet of 3/4-inch-thick marine plywood up to the now-open rear of the boat. Move the plywood until there is a close fit between the plywood and the rear of the boat. Mark the bolt holes of the right-angle brackets onto the plywood with a pencil. Trace the outline of the outside of the rear of the boat onto the face of the plywood that faces into the boat.

Step 3

Cut the plywood so that it fits the rear of the boat, using a power saw. Drill 1/2-inch holes through the plywood, using a drill and 1/2-inch bit. Apply two coats of primer paint or other sealant to all sides and edges of the plywood, using a disposable paintbrush.

Step 4

Apply adhesive marine caulk to the threads of the new 1/2-inch bolts. Apply adhesive marine caulk to the part of the right-angle brackets to which the new transom attaches. Position the plywood transom and insert the bolts through the right-angle brackets and the plywood. Thread the nuts onto the bolts and tighten securely.

Step 5

Cover the nuts with marine adhesive caulk. Apply a bead of marine adhesive caulk around both the inside and outside of the joint between the transom and the hull. Apply two coats of paint in the finish color.


  • This project involves power tools. Please observe the safety precautions recommended by the power-tool manufacturer.


  • You can cut the transom so that the top accommodates a longer-driveshaft outboard by measuring 22 inches up from the bottom of the transom. Mark the wood at that point and draw a line straight across the plywood at that point. Cut along that line with the saw when you cut out the transom.
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