1959 Chris Craft 17′ Sportsman Transom Planking & Framing Update

1959 chris craft sportsman transom framing planking

Given the evidence that it has shrunk – a very wide seam between it and the next transom plank above, I fully expected to release the bottom transom plank.

However, the prospect of first stripping bottom paint lying on my back and then releasing all the fasteners driven through the tails of the bottom planks and into the bottom transom plank was foreboding at best.

Then, when I was having difficulty with the last few fasteners, I called in, RJ, who has what he terms his “special touch” releasing buried wood screws. As the last one backed out, RJ exclaimed, “I think your plank is free already!”
And it was and is. We now know that Chris-Craft moved the final course of fasteners forward from the tails, just enough that they are driven into the transom frame’s bottom bow.

The attempt to waterproof the seam along the bottom edge of the bottom plank was attempted using the oil-permeated canvas we have all seen when releasing bottom planking. Suffice it to say that, like the stuff under bottom planking, this course of canvas had long since lost whatever waterproofing qualities it had in 1959.

When the time comes we will install the bottom plank bedded in copious amounts of mahogany 3M5200.

A combination of finding green, and therefore moisture adulterated, fasteners behind the test bungs I popped, and a ubiquitous design issue that translates into a chronic, although slow leak, we also released the next transom plank.
The issue occurs at both ends of that plank, from its bottom edge up about 2 inches. Chris-Craft originally sealed the seam between this plank and the transom frame member it lands on using the same sealer-impregnated canvas technique.

However, each of the first 3 1954-1959 17’ Sportsman models we have preserved to date tended to seep water through that joint until we bedded them in 3M5200.

Proving that even old boat guys can learn, we routinely release this plank, remove what is left of the canvas and install it anew bedded in mahogany 3M5200.

With Christmas weekend peaking over the horizon, cleaning out the bilge and then pressure washing it will not begin until next Monday.

1959 Chris Craft Sportsman – How To Release Bottom Plank Fasteners

release bottom plank fasteners 1959 chris craft sportsman

The goal here is removing fairing-compound-filled countersinks and releasing the over 1,000 fasteners driven through the bottom planking and chines without damaging the edges of the countersink hole.

We begin with a portable drill and drill bit. (We use a pilot bit because it can withstand lateral pressure without breaking.)

Why drill all these holes? The Rotabroach cutter includes a positioning, spring-loaded pin. Yes, it can position the cutter in the countersink center, but it quickly gets loaded up with residue and fails to pop out once a countersink is opened. Then it walks across the plank until you grab a vice grip, remove the cutter and clean it.

Drilling the pilot hole gives the pin someplace to go without being pressed into the cutter head.

Next clean the hole using a scratch awl, and then the Frearson head slots using a pick, and blow the hole clean with an air chuck. (A shop vacuum will work here if the crevice tool is used, but the blast of compressed air cleans much, much more thoroughly.

Grab the impact gun to which you have fitted a #2 Frearson (Reed & Prince) driver and carefully back the screw out. (The impact gun’s trigger must be feathered so that it turns as slowly as possible for the initial rotations. A portable screw gun can be used, but it is much slower.)

The mini hook comes into play for those fasteners that simply spin in the hole. Carefully work the hook under the screw head and apply a bit of upward pressure by levering against the edge of the countersink. (Yes, “unpleasant” utterances are part of this process.)

Once you have all the fasteners – which you absolutely will not reuse – safely in the recycling bucket, and have teased all the planks off the inner planking, you are ready for the next steps. In the case of the ’59 Chris-Craft Sportsman, since the plywood inner skin presents as almost new, the next step is scraping all the canvas off, cleaning the surface and proceeding to toothpicking every fastener hole in the entire bottom.

Once you have inserted 4 to 5 toothpicks dipped in Gorilla Glue, or about 5,000 in total, into all the fastener holes, and the glue has set, reach for your Fein Multimaster and “shave” the plywood. What a mess!

Time for CPES, 3M5200 and installing bottom planking!

Tools:

  • Rotabroach Cutter Kit – available at Amazon.com
  • Portable drill and pilot bitdrill bit
  • Portable drill for 3/8” Rotabroach cutter
  • Portable impact driver with #2 Frearson (aka Reed & Prince) driver
  • Scratch awl – a Stanley brand awl is available from Amazon.com
  • A mini hook and pick set like this