Small Gouges, Big Consequences: Repairing Champagne’s GRP Hull Before We Get Carried Away

There are moments in boat ownership when enthusiasm needs to be firmly grabbed by the collar and told to sit down quietly.

Champagne, our Thames A-Rater, is back on the river, looking elegant, dramatic and faintly capable of emptying a bank account if left unsupervised. She has already been water-tested and even had a brief return to racing, which is rather exciting. But before we get too carried away with sails, varnish, filming, racing and pretending we know exactly what we are doing, there is a small but important job that cannot be ignored.

Champagne has a couple of small gouges in her hull.

They are not enormous. They are not the sort of damage that makes everyone in the boat park gather round with concerned faces and mugs of tea. But they are there, and on a GRP hull, small damage is still damage.

Before we do too much sailing, they need to be repaired properly.

Why Small Gouges Matter

It is tempting to look at a small gouge and think, “That will be fine for now.”

This is one of those dangerous phrases, rather like:

“That screw is probably tight enough.”

“The weather should hold.”

“I’ll just do a quick coat of varnish.”

With GRP — Glass Reinforced Plastic — the outer surface protects the structure underneath. If the gelcoat is damaged and the laminate underneath is exposed, water can begin to get where it should not. On an older racing boat, especially one we want to restore properly, that is not something to ignore.

A Thames A-Rater may look delicate and glamorous, but underneath the long lines, tall rig and elegant history, she is still a working racing boat. She has to cope with launching, recovery, moorings, river banks, trailers, crew movement, water pressure, knocks, bumps and the occasional moment when the helm and physics disagree.

So the plan is simple: repair the gouges before they become bigger problems.

This Is Not Just Cosmetic

The first temptation with a hull gouge is to think of appearance. Of course, I want Champagne to look good. She deserves to look good. A boat called Champagne should not look as if she has been dragged through a hedge backwards, even if restoration sometimes feels rather like that.

But the real reason for repairing these gouges is protection.

A proper repair should:

• seal the damaged area;
• restore the surface profile;
• protect the underlying glass fibre;
• prevent water getting into the laminate;
• provide a sound base for gelcoat or paint;
• avoid a repair that cracks out again after the first few sails.

That last point is important. A quick smear of filler may look acceptable for about ten minutes. Then vibration, flexing, water and use can expose the fact that the repair was more cosmetic than structural.

The aim is not just to hide the gouge. The aim is to repair it.

Step One: Clean the Area Properly

The first job is cleaning.

This sounds dull, which is why it is important. Many workshop disasters begin because someone wanted to get to the exciting bit too quickly.

The damaged area needs to be washed thoroughly with soap and water to remove dirt, river grime and anything else that has collected on the hull. After that, it should be wiped with a suitable wax-and-grease remover or marine solvent.

This matters because epoxy and gelcoat do not bond well to dirt, polish, wax, grease or old contaminants. If the surface is not clean, the repair may only be attached in a theoretical sense, which is rarely enough when boats and water are involved.

This is the restoration equivalent of exam technique: the boring preparation often decides whether the final answer works.

Step Two: Bevel the Gouge

The next step is to prepare the shape of the damage.

A gouge with sharp vertical edges is not ideal for repair. The filler needs a good surface to grip, so the edges should be bevelled out using something like 80-grit abrasive paper or a small rotary tool.

The idea is to create a shallow, sloped edge rather than a hard-sided hole. A commonly suggested approach is a generous taper, sometimes described as around a 12:1 bevel for structural repairs. For a small surface gouge, the exact geometry may be less dramatic, but the principle is the same: do not just fill a narrow crack and hope.

A bevel gives the repair more bonding area.

It also helps avoid the classic problem where the filler feathers out too thinly at the edge and then cracks, chips or lifts later.

This is the point where patience starts to matter. It is very easy to think, “Surely that is enough sanding.” Usually, it is not.

Step Three: Mix the Epoxy to the Right Consistency

For the actual filling, the plan is to use a marine-grade epoxy system thickened with a suitable filler.

A resin on its own is too runny for this job. It needs to be thickened so that it can be pressed into the gouge and stay there without sagging. High-density filler or colloidal silica can be used depending on the exact repair and product system.

The texture often described is “peanut butter” or “mayonnaise”.

This is wonderfully unscientific language for something that is actually quite important. Too runny, and it slumps, drains or leaves gaps. Too thick, and it becomes difficult to press fully into the damage.

The mixture needs to be thick enough to hold its shape, but workable enough to spread and compact into the gouge.

As someone who spends a lot of time teaching science, I rather like this stage. It is chemistry, materials science and practical judgement all in one small pot. The ratios matter. The mixing matters. The working time matters. The temperature matters. And, as always, the instruction sheet is not just decorative paper.

Step Four: Fill the Gouge Slightly Proud

Once mixed, the thickened epoxy can be applied with a plastic spreader or putty knife.

The key is to press the mixture firmly into the damaged area. The aim is not to gently decorate the top of the gouge, but to fill it properly.

The repair should be left slightly proud — raised a little above the surrounding hull surface. This allows for sanding back later. If the filler is applied exactly level, any shrinkage, settling, sanding or small error may leave a shallow dip.

And a shallow dip will catch the light beautifully every time you look at it, just to remind you that you rushed.

A proud repair gives room for adjustment.

Step Five: Let It Cure

This is the most difficult part of many repairs.

Leave it alone.

Epoxy needs time to cure properly according to the manufacturer’s instructions. That may be around 24 hours, depending on the system, temperature and conditions. Cold, damp weather can slow curing. Warm conditions can shorten working time.

This is where boat restoration and British weather form a partnership designed to test character.

The repair may look ready before it is ready. It may feel tempting to sand too soon. But if the material has not cured properly, sanding can tear, clog, smear or weaken the finish.

So the glamorous restoration activity for this stage is waiting.

Possibly with tea.

Step Six: Sand It Flush

Once cured, the repair can be sanded down.

This is where the sanding block earns its keep. Sanding by hand without a block can create uneven surfaces, finger marks and soft hollows. A block helps level the repair to the surrounding hull rather than simply smoothing the bump.

The first stage can be done with something like 80-grit paper to bring the raised repair down carefully. Then finer grades, such as 150 to 220 grit, can be used to refine the surface.

The aim is a smooth transition between the repair and the original hull.

This is where touch can be more revealing than sight. A surface may look acceptable but still feel uneven under the fingers. Running a hand gently across the repair can reveal ridges, hollows and edges that the eye misses.

On a racing boat, fair surfaces matter. Champagne does not need unnecessary lumps, bumps or rough patches slowing her down — she will have enough trouble with me learning how to sail her properly.

Step Seven: Finish With Gelcoat or Paint

The epoxy repair needs a proper finish.

If the hull is gelcoated, a matching marine gelcoat can be applied over the cured and sanded repair to restore protection and appearance. If the boat is painted, then the repair needs to be finished in a way that is compatible with the existing paint system.

The finish is not just about making the patch disappear. It protects the repair from water and ultraviolet light and helps restore the hull surface.

Once the gelcoat has cured, it can be wet-sanded through finer grades — for example 400 grit and then 600 grit — before polishing with rubbing compound and wax to bring back the gloss.

This is the point where the repair starts to look less like a workshop job and more like part of the boat again.

Matching the Finish: The Awkward Bit

In theory, matching gelcoat is straightforward.

In practice, boats age.

White is not always white. Cream is not always cream. A hull that has spent decades in sunlight, water and weather may have faded, yellowed or changed tone. A brand-new repair can sometimes look cleaner than the surrounding area, which is both satisfying and annoying.

For Champagne, the aim is not concours perfection at this stage. The priority is a sound, watertight, strong repair. Appearance matters, but protection matters first.

That is probably going to be a repeated theme in this restoration:

Safety first.
Sailing performance second.
Beauty third.

Although, being Champagne, she will probably insist on beauty being at least joint second.

Practical Lessons From a Small Repair

This job is small, but it reflects the larger restoration project.

A classic racing boat is not restored in one heroic burst. It is restored through a long sequence of sensible decisions:

• fix the hull damage;
• check the rudder cassette;
• replace unreliable lashings with proper fittings;
• assess the rigging;
• protect the woodwork;
• sort the cover;
• inspect the sails;
• photograph and record the condition;
• decide what is urgent, what can wait and what is merely cosmetic.

The gouges are part of that bigger process.

They are a reminder that restoration is not just about dramatic before-and-after photographs. It is often about tiny jobs done properly before they become large jobs done expensively.

A Personal Reflection: The Boat Park Teaches Patience

One of the things I am learning about boat ownership is that boats are very good teachers.

They teach patience, because rushing usually creates more work.

They teach humility, because even a small job can reveal how much you still have to learn.

They teach planning, because the right repair depends on weather, materials, tools, curing times and the availability of a flat bit of space that is not currently covered in ropes, sanding dust or someone else’s trolley.

They also teach restraint.

The exciting part of owning Champagne is imagining her sailing properly again, tall rig pulling, long hull moving through the Thames, the whole boat looking elegant and slightly ridiculous in the best possible A-Rater way.

But before that comes sanding, cleaning, filling, curing, sanding again and finishing.

The river can wait for a proper repair.

Why This Matters for the Champagne Story

Champagne is not just another boat in the boat park. She is becoming a project, a story, a film series and hopefully a returning racing boat.

That means the small jobs deserve to be recorded too.

A video of a gouge being cleaned and filled may not have quite the drama of a race start, but it is part of the same story. Every repair helps bring her back. Every careful job reduces the chance of trouble later. Every photographed stage becomes part of her restoration record.

And for anyone following the project, it shows the real side of classic boat ownership.

Not just champagne moments.

Also sandpaper moments.

Conclusion: Repair First, Sail Later

The gouges in Champagne’s hull are not the largest problem we will face. They are not the most glamorous job. They will not make the most spectacular photograph.

But they matter.

A GRP hull depends on its protective surface. Damage should be cleaned, bevelled, filled, sanded and properly finished before water and use make the problem worse.

So before Champagne does too much sailing, these small gouges will be repaired properly with marine-grade materials and a patient approach.

It is not the most exciting part of bringing an A-Rater back to racing condition.

But it is exactly the sort of job that makes the exciting parts possible.

Before Champagne can sparkle on the Thames, she needs a little careful mending underneath.