Middle Planks Hung

mid planks donelap bevelThese went a lot faster than the garboard planks. No steam bending needed. There was a lot less white goop too; the dog walking down the street escaped with no goop this time.

A couple of details are interesting. Lapstrake planks overlap at the edges. The “lap” on this boat is 5/8 inch and is, like the edge of the boat’s bottom, a rolling bevel. Getting the bevel right is pretty easy with the use of a temporary batten (that really thin piece) which simulates the edge of the next plank. Then stand a simple lap gauge between the batten and the existing plank to find the bevel angle. Plane along the bevel using the gauge to check for the right rolling angle. Keep the lap flat and free of crowns and all will fit well.

gainsThat is, until we get to the ends of the boat. There’s no overlapping at the ends. So, as we approach the ends, we plane a rabbet into the lap area of the garboard planks, and into the matching area on the middle planks. If one gets this rabbet to be half the plank’s thickness at the end of each plank, the result is nice and smooth at the stems. This area of transition is called “gains.” No, I don’t know the origin or reason for the term. My gains turned out fairly well.

Fastening is with a few screws in the stem, adhesive caulk (3M 5200) at the stems and in the rabbets, and clinch nails every 2 inches.

2 Responses to “Middle Planks Hung”

  1. Jodi Carpenter Says:

    Hi Bob,

    I am building this boat with a group of middle school students after school, and your blog has been a wonderful reference. I became interested in building this boat at the Wooden boat show at Mystic Seaport last June, and I’m hoping to bring this boat to the WBS this year. My question is…both of the garboards are on, and I began beveling yesterday to prep for the middle planks. One thing that was immediately apparent is that I’m going to have to take off more than 5/8ths for the rolling bevel at the bulkheads. The angle is too great for the middle plank to lay flat against the BH. Should I start the gain at the bulkhead even though Harry says to start the gain 8-10″ from the end? Did you come across this problem?
    Thanks for your time, any suggestions would be appreciated! Jodi

  2. Bob Says:


    What a neat project for working with the youngsters!

    My recollection is a couple of years old, and I’m getting old enough to experience “modified history.” :)

    Yet, I do recall that particular lap needing a fairly broad bevel, but not enough to cause me to change the gains. I kept them at the 8-10 Harry recommended and all turned out well.

    I was also a bit skeptical about using the planking outlines strictly as published. I allowed a good 3/4 – i inch of leeway on the original cutting and trimmed then to best fit. Yes, that took more test fits and trips back and forth from the bench to the boat to the bench, but I had the time.

    From what you describe, I can’t quite imagine lengthening the gains. Make sure you get the “hood ends” of the mid planks well positioned on the stem pieces before making that decision.

    In any course, have a great time working with the kids. I’ll be watching for progress photos.

    All the best,