How to Install Bottom Planks in a True 5200 Bottom – 1938 19′ Chris Craft Custom Runabout

Installing the bottom planks can be tedious and is fraught with all manner of challenges.

First and foremost, unless the planks are dry-fit so that the seams between them are of uniform width, you will all but certainly experience and “Oh X$#%^!” moment when try to install the final, chine, plank.

I cannot tell you how many bottoms we’ve encountered that sport the telltale “skinny plank” along the chine. Failing to fit first, mark the edge of each plank heavily and then obey the lines usually translates into a super wide seam, sometime over an inch, and a plank that does not fit at the stem.

Once again we drop screws part way into all of a plank’s holes before setting it in place, and screw each of them in only part way thereafter. Once all the screws are down far enough that the shanks are in the plank’s holes, begin driving them home. (We work from the middle out, but given how narrow the planks are, you can also work from either, or both ends towards the middle.)

When you clean excess 5200 – that which squeezes out – work towards to ancillary goals. Keep the countersinks free of the 5200 so that the 3M Premium Marine Filler can make a purchase on wood, not on slipper adhesive. And, be sure that all seams are filled fair with 5200.

Clean with Interlux Brushing Liquid 333, and then wipe everything down with acetone, which will accelerate the curing process.

Finally, be patient. I do not care what Interlux says, 5200 can have a mind of its own around curing.

Sometimes waiting 2 – 3 days are fine, but we wait longer, at least a week, before we go at the bottom with sandpaper.

You will be helped with being patient as the countersink filling and bottom fairing process is might time consuming when done correctly. Remember, whether it is 3M Premium Marine Filler or some other fairing compound of your choosing, it shrinks as it cures. You want every countersink filled fair to the plank surface. Apply it twice and then sand everything as smooth as you can with 80 grit – no finer, before applying it a third time and sanding again.

Even though the planks were dosed with three coats of CPES before installation, you have likely sanded into the sealed layers, so applying three more coats is not overkill.

We prime all bottoms with five, not three or four – coats of Interlux 2000E Barrier Coat Primer before applying Pettit Hard Racing Copper Bronze Bottom Paint – three coats.