The plan calls for solid wood runners with a layer of metal applied so that the boat tracks better and also is protected for the inevitable dragging that will occur. I used white oak and 1/8” thick by 1” wide aluminum.
Making the Runner
My runners are 59 1/2” long, 1” wide, and 1 1/4” tall. White oak is incredibly tough and rot resistant. There is a 6” long taper cut at each end so they don’t get hung up. The plan calls for 1/4” galvanized bolts. However, the galvanized coating on threads that small don’t leave much purchase between the nut and bolt threads and they stripped under minimal torque. I switched over to regular grade bolts…too cheap to buy stainless.
Determining spacing of holes in relation to ribs. Note the white oak washers.
Drilling the 3/4” counterbore to receive the flat washer.
Drilling the 1/4” hole to receive the bolt.
Installing the Runner
Drill one end hole for each runner and bolt the runner at that end. That hole registers the runner. Align the runners and use the runner holes as a guide to drill through the hull. Insert each bolt before drilling the next hole. This is a lot easier than having to mark each hole location perfectly.
Marking the first hole at end.
Drilling through the hull.
Aligning runners parallel to hull.
Drilling hole at opposite end.
Close-up of bolted runner.
Mary held the wrench inside the hull during tightening. I applied silicon sealant under the runner and in the bolt holes to prevent water intrusion. Here Mary is wiping off excess sealant. NOTE: I tried GOOP Marine sealant and it sets up too fast. Save yourself the hassle and use RTV silicon sealant that is rated for outdoor use.
Bending the Aluminum
Aluminum is easy to bend, but you still have to align the bends with the runner.
Mark the pivot point, clamp it in a vice, and hammer with your well-calibrated hammer arm!
The scrap wedge from cutting the runner is a perfect reference tool to measure your bend.
Copper approved of the results.
Installing the Aluminum
Use 3/4” #8 screws and silicon to apply the runners. Be sure to fill the runner bolt holes with silicon as well.
The runner was aligned to terminate at the inside edge of each outer rib. This allows the aluminum to be screwed securely to the outer rib. You’d hate to have that peel up when going over an obstacle.
View before filleting.
An added precaution is to use thickened epoxy at the of each runner to protect the leading edge from being caught. I also used thickened epoxy to fillet around the perimeter of the runner to slow water intrusion.
In the next installment I’ll discuss installing the floor.
-- Mark, Minnesota