View Single Post
  #2   Report Post  
Wayne.B
 
Posts: n/a
Default retabbing bulkheads on older FRP sail boat....

On Mon, 07 Jun 2004 17:35:46 -0500, Courtney Thomas
wrote:
Advice and descriptions appreciated.
Courtney


============================================

I don't claim any special expertise but have done a few. First thing
of course, is to remove all of the old tabbing. I used sharp
woodworking chisels and a disk sander. Ideally you should insert a
thin layer of structural foam between the bulkhead and the hull if the
builder left a sufficient gap for that purpose (it eliminates a "hard
spot" on the hull which can lead to stress concentration). Next build
up a rounded fillet using expoxy thickened with microbaloons or
fairing compound. The idea is to create a curved surface with about a
1 inch radius which joins the hull and the bulkhead. Small, round
beverage bottles are frequently used to get the desired shape. Allow
fillet to cure and lightly sand. Next step is to apply unthickened
epoxy to the fillet and adjoining surfaces, followed by an application
of 3 inch glass tape, another coat of epoxy, and a second layer of
tape. Apply additional tape if needed for increaded strength.
Repeat all the above on other side of the bulkhead.

Broken tabbing is usually caused by hull panel flex going through
heavy seas, and can indicate that the original designer/builder did
not give enough thought to structural support. Consider adding more
panel support if feasible.