Tuesday, May 1, 2018

Progress of the Sportfisheman

The glassing of Kevin Agee's 26ft sportfisherman has continued. After completing the sides and bottom with a single layer of biaxial fabric cut from a roll 50" wide, the centreline was glassed with two layers of biaxial tape. The transom and bracket followed, also glassed with biax fabric from the roll.
This photo shows all stages of glassing the hull side. The light section in the bow hasn't been started yet. The dark section aft of that has been pre-coated with a layer of epoxy. Aft of that the glass fabric has been laid back against the hull so that the contact face can be wetted out prior to being laid onto the wet epoxy on the hull. This speeds up the wetting out process of the glass. Aft of that the glass has been rolled with ribbed rollers to remove bubbles and a layer of peel ply has been applied over the top with squeegees.
A few days later, the peel ply layer has been removed and the centreline has been glassed with two layers of biaxial tape, from transom to tip of the bow.
The transom and bracket have been glassed, lapped over onto the sides and bottom of the hull. The centre portion will be glassed after the hull has been turned over.
After removing the peel ply, the hull was examined to find and repair any air bubbles that formed in the laminate. A few were found and repaired. Sanding them out with an orbital sander, I could see that most were the result of out-gassing from the wood and one appeared to be from contamination. The out-gassing bubbles have a complete coat of epoxy against the wood, while the contamination bubbles have little or no epoxy against the wood. In this case the contamination showed as a pattern of four fingertips and a palm. The out-gassing bubbles were sanded down to the epoxy coat and the contamination bubble was sanded down to clean wood, to remove the contamination. All were sanded out to form a dished profile with a feathered edge on the glass. Then a patch was laminated into each one, to be sanded flush later.
An out-gassing bubble has been sanded down to remove the glass that hadn't bonded to the wood, forming a dished surface. This is then filled with a glass patch was laid in to fill the depression. This will be sanded flush before the fairing layer is started.
Next task on the list was shaping and fitting the planing strakes, one on each side. The strakes are parallel-sided over part of the length but must be tapered both horizontally and vertically, terminating in a point at the forward end. They must also be planed to a triangular shape so that the hypotenuse matches the slope of the hull bottom over the entire length. Most of the timber can be removed with a power plane, then finished with a hand plane.

We did a dry-fit to check for correct shape, placement and fairness, held by temporary screws. The target is a fair curve when seen from all directions, as well as matching alignment between the two sides when viewed from the front. The screws were used later for alignment to ensure that the strakes were glued on in exactly the right positions.
Planing strakes dry-fitted for alignment check.
Planing strakes glued on. After removal of the screws they will be glassed over.
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