What a grind...

After a month of pulling wiring and extricating plumbing, I am now quite familiar with many of the nearly inaccessible voids and dark recesses of our 1979 M382 Hull#115.  I’ve had a good look at the bones of the vessel and must admit Morgan’s construction techniques on our M382 leave much room for improvement.  The tabbing along many of the partial and full bulkheads is intermittent.   In our 1966 M34, the tabbing between bulkheads and the hull extended non-stop from the hull deck joint to the end of the bulkhead or in the case of a full bulkhead all the way around to the opposite hull deck joint.   

Ok, ok not everyone reading this is familiar with boat construction.  Feel free to skip down the to next paragraph if you are familiar with  the concept of bulkheads and tabbing.  The hull of the M382 consists of layers upon layers of fiberglass mat. These layers are constructed over a mold that provides the hull's basic shape. To retain the shape of the mold once the vessel is subjected to the stresses of life at sea the hull requires internal bulkheads.  Inside the boat these bulkheads appear as full walls (reaching from floor to ceiling) and as partial walls (supports for the counter in the galley, seat backs in the salon, supports for the vee berth, etc.)  These walls are attached to the hull by wide strips of fiberglass mat.  These strips, epoxied to both the walls and the hull, are called tabbing.

In Pilgrim, I have discovered multiple areas where the tabbing runs for 18” then is gone for 12” then runs for 18” and so on.   

Looking down into the locker below the forward galley counter top

The image above is looking down into the galley dry storage locker (the locker floor and hot water heater are removed).  The ¾” plywood walls that serve as supports for the counter top also serve as partial bulkheads.  The areas I ground away the white gel coat down to the brown fiberglass of the hull are lacking tabbing.  Not shown in the image are the two identical areas of missing tabbing just above the top of the picture. 

Amazingly I found similar intermittent tabbing along the full bulkhead just forward of the mast.  This area is accessed by squeezing through a cabinet door under the counter in the head or through a hole in the head counter top.    In the image below, looking down through the hole in the head counter top,  I have removed all the plumbing and the three through hull fittings that served the head plumbing.  It is difficult is see in this image, but the aft bulk head (right in image) lacks tabbing to the hull in an area the spans from the upper, large through hull to the smaller through hull opening lower down.

Space under head counter top with all plumbing removed

Once the grime and gel coat are ground away the missing section of tabbing is much more visible. 

Space under counter top in head after grinding.  Note:  hose in foreground is for shower sump.

Unfortunately while grinding away the gel coat in the head area, I discovered much of the tabbing surrounding the sole stringers, mast bucket stringers, and head pan was installed poorly.  Much of the tabbing in this area was epoxied onto the hull gel coat rather than to the hull fiberglass.   This method of installation is unacceptable as bonding to the gel coat does not provide the strength necessary to sustain loads in this critical location.  Some of the tabbing had already separated from the gel coat.  

In the early 80's Morgan had a recall on M382's due to structural issues in this area of the vessel.  The company sent out repair team(s)  to fix all the M382's. Based on my review of conversations on the Morgan 38 discussion board, I am confident that Pilgrim was visited by a repair team.  I believe that in many areas on Pilgrim the repair team did not remove the gel coat from the hull prior to installing new tabbing.   In many of these areas the tabbing has failed.  Fortunately, I have not discovered any evidence of hull deformation (i.e. irregularities on the exterior hull surface, gaps between the bulkheads and the hull, gaps between the bulkheads and the sole, etc.)  

With all the plumbing gone,  the wiring removed, and the rig out of the boat now is the time to address these concerns. 

We are  also addressing a lack of tabbing in the  quaterberth…

Grinding areas in the quarter berth that will be receiving additional tabbing

And adding tabbed, partial bulk heads under the pilot berth…

Before:

Pilot berth with plywood decking removed. The dividers are not tabbed to the hull?!

After…

New 3/4" plywood dividers that will be tabbed to the hull and the seat back.

We are focusing our current efforts aboard Pilgrim in the cabin from the quaterberth to the door into the vee berth.  Hopefully the areas outside this core area of the vessel do not contain more surprises.

If you want more details and images from this project please check out our photo album – Tabbing Repairs – 2014.

We will continue to add photos to the album and post updates here.

Back to the grind.