Here is what I found when I opened up my ballast tank...

open hole   View down the holes I cut  Bottom of the cabin sole showing dry rot

Haha, well there wasn't sawdust there before I made my cuts.  The hull was covered with crude because she had been in the water so long.

 The centerboard trunk runs down the middle.  It is flat on the top and bonded to the cabin sole with hard-drying bedding compound. The sole is 1/2" plywood. I set my skill saw to 5/16" deep and didn't even score the centerboard trunk. I used a little more depth when in other

places.trun
Centerboard trunk showing flat top with bedding compound

 All picutres below are shown in minuture. Click on the picture to get a big image you can study in detail!

 This is where I think my problems started. Note how cobbly the end of the bulkhead is in the upper left hand corner. It appears to be just globbed on bedding compound.  Note also the dry rot on the plywood bulkhead... 100% coverage, but not very deep yet..

This bulkhead is 5" in front of the step.
Note bedding compound at top of bulkhead


closeup
Detail at centerboard trunk
Detail at port chine

Don't know what those braces are that obviously have rusted screws in them.  They are above the pivot point of the centerboard at about the place where the forward cabin bulkhead runs across the cabin.
 

Forward port 
Forward Starboard

I had a line of blisters running down both sides of the hull.  In pretty much a straight line from about 3-4 feet from the stern to nearly the bow.  I surmised water penetrated the hull at the bow from the damage caused by hitting that stupid trailer cross brace and knocking off the gelcoat.  However, the blisters in a line were baffling.  I called the factory to ask them if perhaps there was a fiberglass ply that was in that approximate location that could be causing blisters from the inside.  Their response was, "no, we've never heard of that problem, don't have any idea what could cause it."    Indeed, there is a fiberglass ply exactly where I predicted it would. I will put a barrier coating on the fiberglass hull in the ballast area to prevent blister causing water from coming from inside the hull.  Thankfully, it appears blisters on Santana's don't come from inadequate hull and exterior

finishes.

Here is the area that will really cause problems, if one does not have adequate access to work.  The chines meet the cabin sole in a sharp angle with very little working area.  I will try different types of paint brushes to get the epoxy up in those tight corners to see which type works best.
 
 




Oh no.  Water was in my aft air flotation chamber so long it caused dry rot in the plywood back there, too.  I don't think I'll do that area right now.  I will see how well I do on the ballast tank area first.  All that sagging bedding compound will have to be removed in order for the epoxy to attach to the actual bulkhead stingers. 
 

Aft air flotation chamber
Aft air flotation chamber

Here is my plan, with concurrence from West Systems.

  1. Clean the crude on the hull with soap and water.  Clean the wood with a 3M scrubby and Acetone.  I will have a squirrel cage fan from an apartment HVAC blowing in fresh air!
  2. Heat up the tank area with a light bulb overnight to aid the wood soaking up the epoxy.
  3. Saturate the plywood with unthickened epoxy until it gets shiny.  This will be done with a continuous, multiple pass, coating going from one end to the other, giving it sufficient time to soak in.
  4. Finish with 3 layers of epoxy with 422 water barrier additive.  One can of the 422 will cover about 225 sq ft of fiberglass along with 80 oz of epoxy.  I estimate the tank to be about 160-180 sq ft, top and bottom.  So it looks like one will need 2 quarts of resin... Wish I'd bought a gallon cause I have some other projects.

I'm glad it's getting cool.  One will definitely need arm protection for this job.