Restoring below the water line?

[JRO_1399]

I picked up a 1995 Nitro fish and ski that was a great candidate for a restoration. It appeared to have been used very little prior to getting left out in the weather for the last 4 of 5 years. Very few scars and not a single screw hole in the transom. The interior was shot and the gel coat was chalky. I wet sanded and polished the interior/exterior and it came out amazing. Everything above the waterline looks like a new boat. Now my problem is the bottom. The bottom is also chalky. Is there a way to return some shine without having to wet sand and polish the entire bottom? I can't imagine trying to sand and polish this thing from underneath much less with the trailer in the way. Any advice is appreciated.

[crank68]

No easy way to get it done ..... gotta sand in most cases. You can try to just buff but the oxidation may come back quick and you’ve wasted a lot of time and effort.

[rgsauger]

You can try Protec restore but it will probably be temp as stated above