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Project Log:  Sunday, January 10, 2010
Home Page > The Project > Project Logs > 1/10/10

After a much-needed break following the end of Phase I, which coincided nicely with holiday season and some other commitments, my thoughts returned to the project shortly after the start of the new year--not that the project was ever out of my mind.

With ongoing paint work in the other shop bay, which would continue over the next couple weeks, I felt I couldn't yet contemplate a wholesale return to the next steps, which would involve additional preparations for and eventual reconstruction of the damaged stern quarters.  Anxious to determine exactly how I'd proceed, I decided to drill a number of core samples in the aft sections of the boat--and adjacent areas--to help me determine the true condition of the laminate that remained in place.

Working from inside the boat, where the condition of the laminate was most visible, I drilled 21 core samples with a 1-3/8" carbide hole saw:  21 because I inadvertently re-used #13, which I subsequently relabeled 13A and 13B.  I chose the test holes' positions based on the visual condition of the laminate in various areas, and also in several seemingly undamaged areas to serve as controls and as a definition to the scope of the damaged areas.  In each case, I numbered the hole and its corresponding plug for future reference.

In addition, there were 6 holes left over from through hull fittings that had been installed; I labeled these accordingly as well:  TH-1, TH-2, etc.

         

         


I also transferred the labels to the outside of the boat for additional location reference.

    

    

In general, the core samples few real surprises.  Where I thought the laminate might be badly damaged and partially delaminated, it was; where I thought it would be sound, it was.  Several of the cores indicated more hull thickness than I'd anticipated (most notably in the bottom sections, closer to the keel), while I was surprised at how thin the remaining laminate was in some of the other areas, where the thickness had apparently been more significantly reduced by various grinding efforts, and possibly consumption during the fire itself.

Here are all 21 core samples together:


Below, please find individual photos and preliminary comments on each core sample taken.  In each case, the photos show both sides of the core sample, and a view of the adjacent hull area around the sampling area.  Where the core sample came out in two pieces, I've included views of both sides of each section, as well as a stacked view showing the pieces in their correct orientation to each other.

Please reference the labeled wide-angle views above to determine the location of each core sample.

1:  Taken from a known bad area.   Total thickness:  about 1/4".  The innermost layer of material (which seemed to be a layer of mat from the mat/roving layup) delaminated from the remainder of the sample during removal, but the outer layers appeared sound.

         


2:  Taken from a known bad area.  Total thickness:  about 1/4".  2 layers of roving from the inside of the sample delaminated from the outer section during removal.

         


3:  Taken near the forward edge of the affected area on the port side, as a sort of control.  Total thickness:  5/16" +.  No delamination during removal, and the sample appeared sound.

         

4:  From fairly high in the topsides, forward on the port side.  Total thickness:  5/16" +.  Laminate relatively sound other than the innermost, exposed layer.

         

5:  From the bottom, down near the turn of the bilge leading to the keel deadwood, slightly forward of the rudderpost.  Heavily reinforced; total thickness about 7/8" +.  Sample showed good condition with no problems.

         

6:  Known bad location, already heavily ground and thin sample anticipated.  Total thickness:  3/16".  Inner layer of roving delaminated from the remaining outer layers during removal.

         


7:  Known suspect location close to sample 6.  Similar sample condition.  Total thickness:  about 3/16".  Inner 2+ layers of roving delaminated from remaining outer laminate during removal.  Gelcoat badly charred on exterior.

         


8:  From higher in the topsides and nearby samples 6 and 7.  Total thickness:  1/2" +.  Inner 2+ layers of roving delaminated from remaining laminate during removal, but bulk of laminate in this area appeared sound.  Slight beginnings of delamination of skin coat from gelcoat on exterior.

         


9:  From well aft on the port side, closer to the transom.    Total thickness:  1/4".  Inner half of laminate delaminated from the outer half during removal.  Both halves appeared sound other than the lack of bonding between the two sections.

         


10:  Taken from an area that had been heavily ground, leaving only the skin coat and gelcoat.  Total thickness:  3/32".

         

11:  Taken close to the turn of the bilge leading to the keel deadwood, and a few feet forward of sample 5.  Similar laminate thickness and condition.  Total thickness:  3/4" - 7/8".  General good condition other than appearance of the innermost (exposed) layer.

         

12:  From a foot or so aft of the rudderpost, port side.  Total thickness:  5/8".  Outer 2-3 layers delaminated from the remainder during removal.  Inner section in sound condition.  Gelcoat and portions of skin coat burned away during fire.

         


13A:  From near the turn of the bilge to the keel deadwood on the starboard side.  Total thickness:  3/4" - 7/8".  Generally sound throughout, but innermost layer or two was partially delaminated from the remainder; I pulled it apart after removal, though it didn't come apart on its own.

         

13B:  From a known bad spot on the starboard side where I'd already ground away much bad material.  Total thickness:  3/32"/  Badly charred exterior gelcoat.

         

14:  From a suspected bad spot high on the starboard topsides, in an area known to be affected by heat and fire.  Total thickness:  1/4".  Inner layer of roving delaminated during removal.  Gelcoat completely burned away during fire, with exposed skin laminate on exterior.

         


15:  From slightly further aft and lower than sample 14.  Overall condition surprisingly sound despite obvious location in the path of the heat and fire damage.  Total thickness:  5/16".  Gelcoat burned away in the fire, exposing crystallized skin laminate layer.

         

16:  From a marginal, heavily-ground section of the starboard side.  Total thickness:  1/4".  Laminate generally sound, though clearly much thickness has already been removed.  Gelcoat burned away in the fire; exterior portion ground away during destructive testing by previous ownership.

         

17:  Same as sample 16, from an area a couple feet removed from 16's location.

         

18:  From high in the topsides on the starboard side, several feet forward of sample 14.  Total thickness:  3/8".  Gelcoat charred and cracked on exterior, but this sample comes from the forwardmost limit of visible fire damage and acts as a sort of control.  Laminate observed to be generally sound.

         

19:  From well aft on the starboard side, aft of the position of the mizzen chainplate location and a foot or two closer to center line from sample 15.  Total thickness:  5/16".  Laminate generally sound with exterior damage from fire (gelcoat completely burned away, exposed skin laminate).

         

20:  From further aft than sample 19, and higher in the topsides.  Total thickness:  3/8".  Laminate generally sound other than obvious external fire damage.

         

Total Time Today:  1.5 hours (sampling); 1 hour to inspect core samples for this writeup

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