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Sunfish Repair Notes

Some of the materials in the repair and maintenanceof fiberglass are highly flammable and should be used with the utmost care. The following items are not to be used anywhere near fire or an open flame (cigarettes, cigars, pipes): acetone, rubbing alcohol, resin.


Materials Needed:
- Cellophane Tape
- Liquid Detergent
- Bucket
- Paint Brush
- Water
- Tire Pump, compressed air

  1. Mix water and 50% soap to make a quart of sudsy water.
  2. Tape over the vent hole located in the forward wall of cockpit of Sunfish.
  3. Prepare second piece of tape for use over drain plug.
  4. Blow air into hull through the drain plug, which is located on the starboard side of the deck, by using your mouth, tire pump or compressed air (max. 3 oz.).
  5. Tape drain plug immediately to trap pressure in hull.
  6. With the paint brush, apply soapy solution around the outside edge of the boat, (where the deck and hull seam is), around the mast tube and daggerboard trunk. Note: You must also soap the bottom of the daggerboard trunk at the same time. Draw a solid bubble across the mast tube opening. Soap all hardware and any locations you suspect might leak, including the splash rail (coaming).
  7. When you locate a leak, circle the area with a grease pencil then rinse the boat with clean water and let dry.
  8. Turn the boat over and test the hull.


Clean the scratched area, using a clean cloth saturated in rubbing alcohol or acetone, to remove all loose debris. Wetsand with #600 grit sand paper, (using a sanding block to avoid digging into the gelcoat). Sand JUST until scratches disappear. Wipe area with cloth saturated in water. Be careful not to over sand. Avoid going all the way through the gelcoat. Confine sanding to scratched are only. Buff up shine with compound.


  1. Flat Surfaces - With the edge of a putty knife, chip away all loose particles of gelcoat from area. Using the blunt edge of knife, tap surrounding area to insure all hidden bubbles are located. Chip them out. Lightly sand hole with #120 grit sand paper, then clean with acetone saturated cloth to make sure area is completely clean of any dust particles. Put cellophane tape alongside the bubble, (see diagram #1), three times the length of the bubble and three layers thick. Run tape perpendicular to tape, overlapping the edges (equal layers thick) to square off patching area (see diagram #1). Mix the gelcoat with catalyst to make a very thick paste, fill in the bubble. Smooth patch by running a clean putty knife over the area, keeping the edges of the knife on the tape (see diagram #2). Remove excess gelcoat with an acetone saturated cloth. Let cure. Finish patch by wet sanding with #600 grit sand paper until patch blends in with the rest of the surface area.
  2. Vertical Surfaces - Follow the directions for cleaning and chipping, mentioned under Flat Surfaces. Place the double layers of tape on, as stated. Before added the gelcoat, place top piece of tape on, adhering from the bottom up. Pour a little gelcoat into the hole. Let cure until sticky, add more gelcoat. Build up slightly higher than the rest of the boat, wet sand as stated under Scratches (see diagram #3).


TOP - Sand with #80 sand paper about a quarter inch down from the lip. Clean with acetone or rubbing alcohol. Take a piece of matting and break it up into shreds. Mix with resin (fine saw dust will also work), and catalyst. Fill in sanded area. Let cure and air test. Sand down until flush with tube side using #120 sand paper.

BOTTOM - Mix resin with shredded mat or saw dust, and catalyst. Be careful not to let mixture get too thick - pancake syrup - and pour enough to cover the bottom and fill in recess (see diagram). Let cure and air test.

MIDDLE - Sand problem area with #80 sand paper and clean. Saturate a piece of fiberglass mat with catalyzed resin one inch larger than the crack or hole. Carefully place it over area, smoothing out any air bubbles with a popsicle stick or hacksaw blade. Let dry and sand until patch is flush with tube and mast slides in easily. NOTE: THIS REPAIR IS FOR HOLES ONLY. IF LEAK OR AIR BUBBLES, FILL WITH CATALYZED RESIN ONLY.

DAGGERBOARD TRUNK - Sand area with #80 sand paper, clean. Mix resin, catalyst, and shredded mat (or saw dust) and fill area, spread with popsicle stick or hacksaw blade. Let cure. Sand with #120 sand paper until daggerboard fits into slot without scratching.


To remove aluminum trim, see page 5.
Rout or sand in center of flange where leak appears. Continue approximately 1" on both sides of affected area to insure complete removal of damaged or imperfect section. Clean. Mix shredded mat or saw dust with catalyzed resin (thick). Fill routed area completely. Let cure, air test.


Turn boat over and sand seam between tub and deck, clean. Mix shredded mat, or saw dust, with resin and catalyst. Pour mixture into a heavy-weight plastic bag and cut off a corner. Apply to top of tub, all around the inside. Let cure, air test.


  1. Rout out hole or crack, enlarging one to two inches. Sand perimeter, to smooth edges and remove all loose particles of gelcoat and fiberglass. NOTE: ROUT THROUGH ALL LAYERS OF FIBERGLASS. Clean away dust particles with an acetone saturated cloth.
  2. Cut pieces of cardboard, mat and woven roving, all one inch larger than hole.
  3. String a piece of thin wire through the cardboard in a "U" fashion, then saturate in catalyzed resin.
  4. Saturate mat and string onto cardboard. Repeat process with woven roving.
  5. Secure tightly to raised wooden structure as indicated in diagram #6 to hold patch into place. Let cure.
  6. Mix resin, catalyst and shredded mat to make a putty. Fill in patched area with mixture. Let cure.
  7. Block sand patched area until it is a little lower than previous contour. lean. Apply gelcoat per instruction under Gelcoat Bubbles.


Tools Needed:
- #30 Drill
- Hammer
- Sharp Edge Putty Knife

  1. Drill out existing rivets with #30 drill and mark old holes.
  2. Patch with catalyzed resin.

Tools Needed:
- Pop Rivet Tool
- 1/8" Pop Rivets
- Pliers - Drill

  1. Place boat on saw horses.
  2. Leave a 12" overhang on stern.
  3. Starting at point A, press the trim onto the boat. Use the head of a rubber mallet placed horizontally between you and the boat. Push with your stomach to hold the trim in place as you drill. Drill only through the top layer of aluminum and fiberglass. DO NOT DRILL THROUGH BOTTOM LAYER OF TRIM. Be sure to drill new holes, judging by grease pencil marks of existing holes. Insert new rivets and finish.
  4. Bend stern piece around corner (use gentle pressure to bend). If a bump appears, crimp down with a pair of pliers with tape on the jaws to eliminate gouging trim. Saw off excess.
  5. Bend next piece (#2) around bow using same procedure as steps #2 and #3. Attach.
  6. Bend piece (#3) around stern following step #3.