Transom Replacement with a plywood core
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Now you will laminate your new inside transom fiberglass skin. The lamination schedule for each boat will vary, but in general, you will be looking to build up to the original thickness. The new inside skin will be much stronger, and better bonded to the core because of the superior materials (epoxy and biaxial fiberglass). To build up the inside skin you will need multiple layers of wide biaxial cloth, normally 50" wide. Each layer of the inside skin will overlap to the sides and bottom, first layer at about 6", then each subsequent layer another 2". Each layer is a little wider than the one it is being laid over. Now is when the transom template comes in handy, you use it trace out your inside skin pieces
A little more about Biaxial Cloth: Biaxial Cloth is available in several weights. In general the lighter the cloth the easier it will be to wet out and work with, but this will also mean many more layers to build up a desired thickness. The heaviest biaxial cloth we normally recommend for amateurs is 1708. 1708 consists of 17 oz of biaxial cloth with an 8 oz matt stitched to the back side for a total of 25 oz. It is important to only use biaxial/matt which is epoxy compatible. Not all cloths are epoxy compatible! Read more on wetting out 1708 if this is your first experience. Here are some important tutorials to understand
Wetting out
Epoxy basics
From our howto section: Howtos
Below is a picture of the Grady White transom with the new biaxial glass inside skin. Notice the overlaps up the side and bottom, also wrapped over the top of the motor cut out.
from the outside
Your transom is now structurally complete. All that remains is to tie your transom into the stringers using stringer splices. (This assumes you are not also replacing the stringers of your boat). Epoxy glue into place wood stringer extensions which match the thickness of the core of the stringers. Grind back at a beveled edge the fiberglass covering of the existing stringer stub. Repeat the epoxy fillet and tabbing procedure used to tab in the transom core, being sure to overlap the old stringer by at least 6". The stringer is also tabbed to the new inside transom skin. Use the same 12 oz biaxial tape for the stringer tabbing. After the tabbing, you will wrap the entire stringer spice (overlapping up the old stringer) with enough heavy biaxial cloth to build up to at least the same thickness as the skin of the original stringer.
The boat is now ready to be put back together. While the structural aspects of the rebuild are the same from boat to boat: marine plywood, epoxy, tabbing, cloth, etc..., each boat design will be a little different in how it should be taken apart and put back together. You do not necessary have to follow the same procedure as the example in this tutorial. In the case of our example boat, the owner simply epoxied into place the cut out portion of his motor well. Butt blocks epoxied to the underside of the parts were used to make a lip for gluing the two edges of fiberglass. Using epoxy fairing compound the joint was then faired out smooth.
Many of our customers use the rebuild as an opportunity to completely change the layout of their transom; single to twin, closed transom for bracket, raised transom for longer shaft engine. We used the Grady White as the example for our tutorial because of the quality of work, quality of materials, and it is a good representation of a common rebuild. You can read through many rebuild threads in the repair section of our message board To get specific technical support for your boat, register for the forum and start a new thread for your project. We will help walk you through the process. This is a free service to customers who get their materials from our store. We keep in stock, and ship within one day, all the materials one needs for a transom job. Our prices are extremely competitive and quality is second to none.
