Last year, Maddie's mother (my future mother in law) kindly asked for me to build a gangplank. The thought of us leaping over the water to get from deck to dock every time made her worry. In the essence of time and cost, I made a very quick but serviceable gangplank.
I used pressure treated lumber from Home Depot for the plank and rat bars. I drilled holes in the gangplank to secure the rat bars with line. I also secured the gangplank to the toe rail using soft shackles.
The wood in Home Depot is all flat sawn, so I selected the least horrible cut of wood (2"x12") for $12. The wood for the rat bars (1"x2") was another $6, so for $18 I had a functional ganplank.
I drilled holes slightly smaller than the stanchions, and pounded them into place. I then used a dab of epoxy resin to glue the stanchions and rat bars in place. It was more of a rushed job, I figured we would use it and then stop using it soon after.
I oriented the grain of the wood so when it warped it would cup rather than dome. I figured if we did use it for a long time, it would be better for our feet to be slanted towards the center rather than off to the sides.
The rat bars proved invaluable this past winter! When the plank was covered in ice, the heel of our shoes would hook on the bar to keep us from sliding down the plank and into the water.
After 1 year with the gangplank, we both love it and want to build a much better one. The old one did warp during the year, and the cupped shape is good for keeping your feet centered over the board no matter what the conditions. The problem is the stanchions are locked into the warped plank and have since tipped inwards. The end of the plank does rub on the pier and has worn the plank significantly.
The 2x12 served its purpose and the price was excellent, but now that we know we like having a gangplank, we decided to build a nice one!
A 2x12 is not actually 12 inches wide, but actually around 11.5 inches. Then the stanchions take up another 3 inches, which brings the usable width down to around 8.5 inches. When you factor in the warped board causing the stanchions to lean in, you end up with around 5 or 6 inches of walking space. We decided to make the next one much wider! 18 inches wide to be precise! And to make it pretty as well!