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Customer Projects

Subject: Sailboat Transom Repair

Date: March 2011

Note: all images can be seen in larger versions by clicking on them.

This is a picture profile of a transom repair on a centerboard sailboat. Our compliments go to the family that made this repair, both for the quality of their procedures and the detailed pictures which make it possible for us to pass this information along to you. What prompted the repair procedure was the owner’s observation that the fiberglass was delaminating from the wood core, and cracks in the fiberglass. A little additional digging revealed that the wood core was compromised. — Doc

Picture 1, transom from the outside
Picture 2, transom from the inside

Pics 1 & 2: This is the boat, outside and inside, before the repair began.

Picture 3, fiberglass removed

Pic 3: The fiberglass has been removed and the bad wood is torn away.

Picture 4, back seats removed

Pic 4: The back of the seats have been removed, exposing the flotation-foam.

Picture 5, floation foam removed

Pic 5: With the foam removed, more transom wood is exposed, and the inside laminate of the hull. This section of the seating on both sides will remain removed, since it was not an area where anyone ever sat.

Picture 6, tear-out continues

Pic 6: The tear-out continues…

Picture 7, using a wedge to break the wood

Pic 7: A wedge is used to break away the wood core.

Picture 8, main piece came out in one piece

Pic 8: The main piece of transom wood came out in one piece, but a thin veneer of plywood remained attached to the outer fiberglss skin.

Picture 9, inside view after wood core was removed
Picture 10, inside view after wood core was removed

Pics 9 & 10: Inside views after the main part of the wood core has been removed, leaving only the veneer attached to the transom fiberglass.

Picture 11, cardboard template in place

Pic 11: Cardboard is taped in place to make a template for the new wood piece.

Picture 12, new wood with holes drilled

Pic 12: Holes were drilled in the new wood so that all thru-hull penetrations would be through epoxy and not through wood. Our customer reported that the challenge was keeping track of these holes through the fiberglassing part of the repair.

Picture 13, new wood testing for fit

Pic 13: The new piece is placed for fitment.

Picture 14, treating the new wood

Pic 14: Both sides of the new transom were heavily treated with CPES*. Holes were filled with Layup & Laminating Resin* and West System 406 Colloidal Silica. Duct tape was placed under the holes and peeled off after the resin cured.

Picture 15, voids filled with L and L

Pic 15: Voids and pocks are filled with L&L resin* and silica filler before installing the new transom piece.

Picture 16, heavy coat of resin added

Pic 16: A heavy coat of L&L resin* and silica (as a thickener to hold the resin in place on vertical surface and to help fill the voids) is applied. A heavy coat of L&L* (without silica) filler was also applied to the transom piece to make sure there would be no starving of the bond.

Picture 17, new piece being bonded in place

Pic 17: The new transom piece being bonded in place using L&L resin*. One needs to be careful not to permanently bond the bracing piece to the transom. Polyethylene plastic sheeting should be used wherever feasible to prevent bonding.

Picture 18, outer view of bracing

Pic 18: Outer view of bracing for the bonding process.

Picture 19, new core in place

Pic 19: The new transom core is in place.

Picture 20, outer skin with imprefections

Pic 20: The outer skin had issues, including dents on each side where there were structural through-bolts. The bolts were removed, the dents filled, and then additional glass added to the outer shell for support.

Picture 21, filling of boarder between transom and hull

Pic 21: A very heavy filet of L&L resin* and 406 silica filler was applied all along the border of the transom and hull to increase the strength of the corner and to provide a smooth surface for the new fiberglass.

Picture 22, before fiberglass install

Pic 22: Before installing the fiberglass sheet shown here, two four inch strips of fiberglass (one over the other) were laminated over the filets shown in the prior picture. L&L resin* was used for all of this fiberglassing, and our customer commented that it was great resin because of its long work time and gradual set up.

Picture 23, 2 extra layers of fiberglass installed

Pic 23: Two additional layers of fiberglass were installed over the transom. Note that the glass cloth virtually disappears after the L&L Resin* is applied.

Picture 24, fiberglass trim strip

Pic 24: The fiberglass trim strip is bonded back in place.

Picture 25, outer skin filled and smoothed

Pic 25: The outer skin was filled and smoothed, using L&L resin* thickened with filler where appropriate.

Picture 26, building up low spots

Pic 26: Building up low spots and indentations in the outer skin before glassing over it.

Picture 27, sizing outside fiberglass

Pic 27: Sizing the outside pieces of glass. The second piece overlapped the first by about a half inch all around, so precise placement of each was critical.

Picture 28, Temporary seat plugs

Pic 28: Temporary seat plugs for areas where the seating was removed.

Picture 29, tansom after sanding faring coat

Pic 29: The inside of the transom after sanding the faring coat.

Picture 30, hardware in place outside view

Pic 30: Hardware is re-installed.

Picture 31, hardware in place inside view

Pic 31: Inside transom hardware in place.

Picture 32, The clean-up crew

Pic 32: Our customer commented: “The clean-up crew”.

* These products are unavailable, we are selling comparable products that will perform these same tasks. Feel free to contact us if you need assistance with which products to use.

Have questions?

Contact us by phone 206-364-2155 or e-mail (send us your pictures) at drrot@rotdoctor.com and we will gladly answer questions about our products or how to apply them. With 20+ years of experience and many more in the boating and construction industries, not much surprises us. We are here to help our customers solve their issues. Let us help you to not have any surprises in your repair project.

Our business hours are 6:30 AM to 5:30 PM Pacific Time, Monday–Friday.
Tech support is available over weekends and holidays 8:30 AM to 5:30 PM Pacific Time.

The Rot Doctor, Inc.
P.O. Box 30612, Seattle, WA 98113
Voice: 206.364.2155    Fax: 206.364.4744    E-mail: drrot@rotdoctor.com
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