As a result of a bridge vs. mast accident resulting from a crew malfunction related to tabernacle operations in 2004 I needed to do some repairs to my mast base support system on my 1965 Pearson Ariel. For a more detailed discussion of this repair with photo documentation, please see my Ariel web page:

http://www.solopublications.com/sailarir.htm

Although like many other Ariel owners, I wanted my main bulkhead to be a strong as possible, it is worthy of note that after forty years of successive owners riding a Pearson Ariel hard and putting it away wet caused no visible deformation of the strong back as of the autumn of 2004.

I removed the Formica on the aft side of the strong back and sanded both sides of the strongback. I chased a few cracks and voids, but those led led me to workmanship and assembly issues that resulted during construction forty years ago when my boat was built.

I filled a few voids and strengthened a few areas. The bulkhead and strong back have served three owners well over the years. My somewhat destructive examination continued to show virtually no bulkhead damage Both professionals with whom I consulted did not feel that through bolting steel plates on either side of the strong back would be the best solution to strengthening the mast support system. In my boat there was no evidence of sagging in the strong back.

Once the teak doorframe was removed, it was apparent that the horizontal beam above the door was level. One of the vertical frame members was actually vertical, but the other is not, so that the door opening is a lopsided trapezoid. Since the plywood opening is cut this way and there is no separation from the hull on either side or underneath, I must conclude that this “as built”, rather than “as failed”.

Although the Main-salon-side plywood bulkhead panel was not glassed to the cabin liner, I could see over this panel to what appears to be a glassed seam between the strong back and the deck. This seam was solid and there was no indication of sagging or separation. The area above the plywood on the Main Salon side of the bulkhead looked fresh and solid. I came to the same conclusion by looking at the seam between the strong back and the underside of the deck from the V Berth side. Removal of the paint from the strong back confirmed that conclusion.

The cracks that I chased and the voids that I discovered were probably left by the builders (the failure to wet out tabs holding key braces in place, voids in the fiberglass, (the use of AC plywood with significant internal voids, etc.). So I would have to say that my boat might have been both hastily built, but it was also overbuilt. The Pearson Ariel is sort of like a Sherman tank built by the low bidder. This is one strong boat, albeit one built somewhat strangely in places.

Because it is conventional wisdom to strengthen the strong back, I contracted for reinforcement by a professional. My contractor installed unidirectional cloth and triaxial cloth. This was glassed onto the bulkhead and strong back in a sufficient number of layers to reinforce the strong back/bulkhead without drilling holes through it or installing steel reinforcement plates as have been used on some Ariels. This solution provided for the strong back to be glassed to the underside of the deck forward of the bulkhead and to the cabin liner aft of the bulkhead. When repairing the top deck, the new top laminate, bottom laminate, core, and cabin liner were reconstructed as an integral unit. Thus the strong back, cabin liner and deck now function as an integral unit. Thus there is no longer a void above the plywood section of the main bulkhead on the main salon side. This void was originally filled by that strange foamy wire-reinforced trim piece. That piece was glued into the void above the plywood. Those little wires are sharp and hard to remove.

The longer bolts in the mast base that had been inserted in the foreword two holes were seriously bent as a result of the mast vs. bridge accident. The bolt holes for these bolt were directly above and ran through the stong back. They penetrated the strong back directly above the doorframe. Their securing nuts were captive inside the beam. Inspection holes were provided by the manufacturer in the bottom of the beam. Those holes were drilled completely through the teak door fame as well. The beam prevented the lower portion of the bolts from bending. In the accident, the bolts were pulled upward. The bends in the bolts occurred at the very top of the bolts. The angle of the force of the impact pulled the longer forward bolts upward, and the shorter aft bolts downward as the mast step plate rotated aftwards into the deck upon impact with the bridge. This effectively crushed the deck beneath the mast step. This entire area was rebuilt as an integral unit, and the forward boltholes were relocated.

The cabin liner in the main salon was obviously distressed as can be seen in the images on my above referenced web page. Less severe distress was evident in the forward salon, but some cracking in the lower laminate occurred.

The shorter bolts were driven down through the cabin liner causing the liner to crack and shatter.

The cracks in the bottom laminate were removed by grinding, as was the paint on the central section of the strong back.

Multiple layers of vinyl ester resin and fabric were added to the damaged area and to the strong back to tie the deck section to and reinforce the strong back. Again there was no damage to the strong back due either to the accident or to cumulative stress to this area.

The application of glass to both sides of the strong back and to the deck sections forward and aft of the strong back created a very strong integral structure to support the mast.

The strong back area (both sides and bottom) was reinforced with multiple layers of vinyl ester saturated fabric including unidirectional cloth and x mat.

The lamination extending from the cabin liner aft of the bulkhead around the strong back to the lower deck laminate in the V Berth area is continuous and seamless. The seam between the remaining Formica and the original gelcoat cabin liner and deck section was sealed with 3M 5200 and topped with a bead of 3M 5200.

I know that all of the above is counter to the prevailing discussion on this page. My point in adding this post is to indicate to those who may be interested that solutions are available other than the removal of their strong backs or installing often unsightly and always conspicuous steel plates on the bulkhead. The choice is a matter of approach to solving a real or assumed need to strengthen the mast support system. Regardless of what is done to this area, the cored deck section beneath the mast as installed is a vulnerable area for compression. Creating an integral unit (deck, cabin liner, and strongback) in my opinion solves this problem.