What We Found on a Pontoon After Winter at Crown Harbor

A Full Winter at Crown Harbor — What We Walked Into

The owner called in late May, a couple weeks before Black Boat Weekend. His 26-foot Bennington had been sitting on a covered lift at Crown Harbor Marina in Cornelius since October. He hadn't checked on it once all winter. When I pulled up to the dock, I could see the waterline ring from twenty feet away.

The pontoon tubes had a thick green-brown algae band running about eight inches above where the current water level sat. With Lake Norman running 2–3 feet below normal this year due to the drought, more of those tubes were exposed than usual — and every inch of that exposed aluminum was oxidized.

What Six Months of Sitting Does to a Pontoon

Here's what the walk-around revealed:

• Pontoon tubes: Heavy algae buildup from the old waterline down, plus a wider-than-normal oxidation band where the drought had dropped the water. The aluminum had gone from silver to a dull gray-white.
• Gel coat: Yellow-green pollen film baked onto every horizontal surface. Underneath the pollen, oxidation had started — not severe, but enough that a finger wipe left a chalky residue.
• Vinyl upholstery: Mildew in the seams of the captain's chair and along the back bench where moisture had been trapped under the snap-on cover all winter.
• Waterline ring: A hard mineral deposit line roughly 3 inches wide — calcium and iron from Lake Norman's water mixed with algae residue. This is the line that doesn't come off with soap.

The Process — How We Brought It Back

Pontoon Tubes First

We started with the aluminum tubes because they take the longest. I sprayed aluminum brightener section by section — you can't let it dry on the surface or it'll etch the metal. Applied it, let it dwell about 90 seconds until the algae started breaking down and turning white, scrubbed with a medium-bristle brush, and rinsed. Two passes on the worst sections near the waterline.

After the algae was gone, I hit the oxidized aluminum with a marine-grade compound on a wool pad. This is where you see the real transformation — dull gray aluminum coming back to a bright silver finish.

Gel Coat Correction

The hull sides and deck got our standard three-step process: wash and decontaminate, compound with a cutting pad to remove the oxidation layer, then polish to restore clarity. On this boat, the oxidation was light enough that we didn't need to wet sand — just compound and polish brought the gloss meter readings from the low 60s up to 88.

The pollen film came off in the wash step. What was underneath — the actual oxidation — required the compound step. A lot of people think washing removes oxidation. It doesn't. It just removes what's sitting on top of it.

Waterline Ring

The mineral deposit line needed a dedicated pass. I used an acid-based hull cleaner on the waterline, let it dwell, agitated with a stiff brush, and rinsed. On the stubborn sections — particularly around the stern where water sits longest — I followed up with a clay bar to pull the embedded mineral deposits out of the gel coat.

Interior and Vinyl

The mildew in the upholstery seams got a marine vinyl cleaner and a detail brush to work the solution into the stitching. Most of it came out. One section on the captain's chair had mildew that had been there long enough to stain the thread — that's permanent, and I told the owner as much. Being honest about what comes out and what doesn't is part of the job.

After cleaning, every vinyl surface got a UV protectant to slow down the next round of fading and cracking through the summer months.

Why This Matters Before Black Boat Weekend

Black Boat Weekend is June 19–21 this year, and it's the biggest show day on Lake Norman. Five hundred boats on the water, everybody looking at everybody else's ride. The owner wanted his Bennington right before the event, and now it is.

But here's the bigger point: the longer a boat sits, the harder the correction becomes. This pontoon sat six months and needed a full day. If it had sat another season without a detail, that aluminum oxidation would have gone from surface-level to pitting — and once aluminum pits, you can't compound it back. Same with the gel coat. Light oxidation corrects in one pass. Heavy oxidation requires wet sanding, which means removing actual material from the surface.

Mobile Dock Service Across Lake Norman

I come to your dock. Crown Harbor, Safe Harbor, River City Marina, Holiday Harbor — wherever your boat sits on Lake Norman, I bring everything to you. No hauling, no trailering, no marina scheduling headaches.

I'm Glidecoat Pro Certified with over 1,200 boats coated and detailed on this lake. I measure results with a gloss meter because I don't guess whether the correction worked — I verify it. On this job, we went from 62 to 88 on the gel coat and restored the aluminum tubes to near-new reflectivity.

If your boat sat all winter and you haven't touched it yet, now's the time. Black Boat Weekend is two weeks out, and my schedule fills up fast heading into June. Call me at (704) 594-3948 to get your pontoon back to where it should be before the biggest weekend of the summer.