Blind Hole Patch

19 Jul 22:

Have a hole in your pontoon hull and not sure how to repair it? Here's how, straight out of the Laser Performance Repair Manual.

 

1965 Alcort Sunfish WAVE 23 Nov 19 Blind Hole Patch Installation

23 Nov 19:

WAVE has a few areas of fiberglass damage, some will require that blind hole patches be installed inside the hull, where the area is not accessible from the other side. To do this we followed the LASER PERFORMANCE Repair Manual and made blind patches, they are inserted through the hole in the hull, pulled snug against the inside of the hull with strings and tied off until the epoxy dries.

WAVE has crushed fiberglass on her chine that will need to be removed and replaced. We'll file it out with a diamond file.

There are a couple of spots where there are gelcoat cracks, we'll skim over those with a sealer coat of thickened epoxy.

I made a mistake installing a transom drain plug, the plan is to repair the transom and get rid of the big hole at the waterline.

Aft keel.

Bailer hole.

A walkaround.



Good shop tables are hard to find!



We filed out the broken fiberglass bits, then sanded the edges with 60 grit on a DeWalt random orbital sander, hooked to a Dust Deputy cyclone and ShopVac. We taper the edges down so that fiberglass cloth can be overlapped. Protective gear includes a hat, goggles, respirator, gloves and a long shirt.

The starboard forward block is loose, we'll push it back in to place after the bottom is fixed.

The center forward foam block is in good shape.

We get a lot of our supplies from Jamestown Distributors, and they picked us to be on their Ambassador Team. We use their TotalBoat products alot and like them, they ship free and the cost is low. They provide some of the products free for us to use, we like that, especially the THIXO, very happy with its performance.

We also like to take the shipping boxes and repurpose them, today this box will be cut up to make up a blind patch.

The blind patch consists of a cardboard backer, that helps keep the woven roving fiberglass cloth stiff. The entire patch gets saturated with thickened epoxy, strings pull the patch flush against the inside of the hull.

We put copious amounts of TotalBoat THIXO on the cardboard, then lay the woven roving fiberglass cloth over the top of that and press the cloth down into the THIXO.

More THIXO is dispensed onto the blind patch.

The patches are inserted into the hull and pulled tight against the inside, tied off with the strings to keep the backer in place while the epoxy dries.

Added THIXO to the edges of the bailer hole.

We might try something different, use a thick layer of THIXO to replace the fiberglass cloth. I'll have a better idea when I sand the repair.



Log of WAVE.

2003 Vanguard Sunfish Repair

18 Mar 2015:

Going to fix up "Crystal," a 2003 Vanguard Sunfish. She got damaged during a storm and need repairs to punctures and abrasions in her hull.

Transported her to the house, I think she is secure...

From SBR 4: Jun 2014 -

The keel was damaged by rocks on a seawall. We will use a blind patch for this repair. A blind patch is a cardboard/fiberglass/epoxy backer that gets inserted into the hull and pulled tight, once it dries you can build up layers of fiberglass to repair the hull.

From SBR 4: Jun 2014 -

From SBR 4: Jun 2014 -

From SBR 4: Jun 2014 -

Dock bolts punctured the chine.

From SBR 4: Jun 2014 -

From SBR 4: Jun 2014 -

From SBR 4: Jun 2014 -

More seawall damage.

From SBR 4: Jun 2014 -

We use a diamond file to remove broken gelcoat and crushed fiberglass. File til you get rid of the loose fiberglass cloth fibers and loose fiberglass. Then fair the edges of the hole, that creates more surface area for the replacement epoxy and fiberglass to attach to. We like epoxy resin vs polyester because it bonds well, has better structural qulaities and doesn't smell as bad.

From SBR 4: Jun 2014 -

From SBR 4: Jun 2014 -

From SBR 4: Jun 2014 -

From SBR 4: Jun 2014 -

You can file all of this away or use a spiral saw to cut the big chunks off. Set the drill bit to only cut the hull, if it is too deep it can cut internal parts or the cockpit.

From SBR 4: Jun 2014 -

Filed, sanded and faired for patch.

From SBR 4: Jun 2014 -

The finish on the hull is oxidized, stained and sunburned. We will sand off the oxidation, clean the stain with Iron Out, wet sand and wax. Patched areas will get touch up coverage of paint.

From SBR 4: Jun 2014 -

Half of the port hull sanded and started on the starboard side.

From SBR 4: Jun 2014 -

14 Feb 2015: Crystal awaiting repairs. But a note here is that it is nice to have a spare cover to protect the boat while work is being done, in our case from pine sap, flying pine cones, dive bombing birds, bugs, dirt etc...that way work doesn't have to be redone.

From SBR 4: Jun 2014 -

04 Mar 2015: Crystal got to be the first boat on the new finishing dolly. The dolly is a copy of the "finishing dolly" that is used at Laser Performance with their Sunfish and Lasers.

From SBR 4: Jun 2014 -

From SBR 4: Jun 2014 -

From SBR 4: Jun 2014 -

Feathered the keel with a dual action sander. The paint stick will be used to reinforce the backer patch.

From SBR 4: Jun 2014 -

11 Mar 2015: Trimming out some heavy weight buckram cloth, about an inch wider all around than the repair. The buckram is stiff fabric that will add stiffness to the repair while it dries inside the hull. It also will keep the tie strings from pulling through the epoxy wetted cardboard.

From SBR 4: Jun 2014 -

Traced the repair area onto the cloth so we know where to put strings through. The strings are used to pull the patch tight against the inside of the hull while it dries.

From SBR 4: Jun 2014 -

Here is the blind patch, which consists of a paint stick, buckram, cardboard, woven roving fiberglass, epoxy resin, bridging filler and strings.

From SBR 4: Jun 2014 -

Here is the blind patch, which consists of a paint stick, buckram, cardboard, woven roving fiberglass, epoxy resin and strings.

From SBR 4: Jun 2014 -

Blind patch inserted into keel and strings tied tight to pull it into position against the inside of the hull. Then I wedged sticks into place to pull it tight and made sure epoxy was contacting the hull all the way around the edges.

From SBR 4: Jun 2014 -

Cut fiberglass for blind patches about 1 inch wider than the hole. Clean broken fiberglass away from edge of hole with a file and clean inside the hull with acetone or mineral spirits.

From SBR 4: Jun 2014 -

Cut a piece of cardboard to pull the fiberglass flat against the inside of the hull. This is a test fit, it need string or wire to pull it back flat inside the hull.

From SBR 4: Jun 2014 -

Used a screwdriver to poke holes for the strings (whipping twine).

From SBR 4: Jun 2014 -

Patch pushed through and pulled tight against inside of hull. Tie the string off to a stick or more cardboard.

From SBR 4: Jun 2014 -

I used Marine-Tex on the keel gouges. Main reason is that's what I had. Pettit EZ Fair would be easier to sand.

From SBR 4: Jun 2014 -

From SBR 4: Jun 2014 -

Blind patch drying.

From SBR 4: Jun 2014 -

16 Mar 2015: The deck is oxidized, but not too bad. Waxed it with 3M Fiberglass Restorer and Wax, used different bonnets to apply and remove the wax, then buff and polish the surface.

From SBR 4: Jun 2014 -

From SBR 4: Jun 2014 -

From SBR 4: Jun 2014 -

Replaced the drain plug.

From SBR 4: Jun 2014 -

From SBR 4: Jun 2014 -

From SBR 4: Jun 2014 -

Peeled off an old Sunfish decal.

From SBR 4: Jun 2014 -

Used Marine Tex epoxy putty then Pettit EZ Fair to fair the repairs. Sanded with 120 grit on a DA sander then sprayed 4 coats of Rustoleum Gloss White.

From SBR 4: Jun 2014 -

From SBR 4: Jun 2014 -

From SBR 4: Jun 2014 -

From SBR 4: Jun 2014 -

From SBR 4: Jun 2014 -

Sat in the moaning chair for a while after some paint bubbled while spraying the hull.

From SBR 4: Jun 2014 -

17 Mar 2015: All is well, last coat drying.

From SBR 4: Jun 2014 -

18 Mar 2015: Bought a new random orbital sander.

From SBR 4: Jun 2014 -

Applied a new Sunfish sticker.

From SBR 4: Jun 2014 -

From SBR 4: Jun 2014 -

Crystal loaded up on her trailer, waiting to go back home!

From SBR 4: Jun 2014 -