Tackling TAKARA thru-hull repairs on
Upgrading our sailboat’s navigation instruments called for eliminating one thru-hull fitting and reducing the diameter of another by ⅛". Takara, a 1974 Irwin 30 Competition, has a one-piece molded fiberglass and polyester hull with alternating layers of hand-laid mat and 24 oz. woven roving. Her original instrument set included a pair of 2 ⅛"-diameter transducer thru-hulls in the bow. Upgrading to modern instrumentation standards required installing an NMEA 2000 network instrument that was 2" diameter.
The project, while simple in scope, posed a few complications:
The two original thru-hulls were quite close together
These thru-hulls were close to the centerline of the bow
From the inside, the thru-hulls were near some laminated stiffening for the bow as well as some tabbing to the inside liner
We reached out to Gougeon Brothers, Inc. and were connected with Technical Advisor Don Gutzmer. We sent some pictures over and he assessed our situation. This was truly the best thing we could have done. Don’s technical expertise was evident throughout our discussions.
He recommended we start by reinforcing the inside area with two layers of biaxial fiberglass cloth before making the repair from the outside. On the outside, to eliminate the obsolete thru-hull, we needed to taper the fiberglass at 12:1. Repairing this
unneeded hole required eight layers of 17 oz. biaxial fabric with mat. The resized thru-hull would need a couple of layers on the outside as well. Since it only had to be ⅛" smaller, it could be filled with a “puck” of thickened epoxy, covered with two layers of glass, and re-drilled.
With our game plan in place, we gathered the tools, materials, and West System® Epoxy for the job. We easily removed the old thru-hull transducers. Next, we began grinding to prepare the inside of the hull for proper adhesion of two layers of 17 oz. biaxial fabric.
To make a clear area for applying the reinforcing layers of fiberglass on the inside of the boat, we removed an original piece of fiberglass tabbing. We then used a piece of clear plastic sheet to make a template for cutting the two layers of fiberglass cloth to be applied inside the hull. The template made it a breeze to cut the fabric to the correct shape.
With the inside prepped and ready for new fiberglass, we moved to the outside of the boat to begin the more significant elements of the repair. On the exterior, we marked a circle for the proper 12:1 taper required to eliminate the unneeded thru-hull. We made a template for the new glass cloth as we had done on the inside of the boat.
Don recommended a layup schedule of eight layers of 17 oz. biaxial fiberglass fabric to match the thickness of Takara’s hull. This was the perfect thickness and left us with very little sanding and fairing to do. Nice to have experts working with you!