AluminumAlloyBoats.com

I have a 2325 pacific unpainted on bottom. had on mooring , just took out only to find barnacles all over. I have scraped them off except for that dam "disc/shell" they leave behind. Anyone know what is best/safest way to remove them??

The easiest way will be to firstly get your boat off the trailer using old car tyres to both cushion & support it so that one side of the hull bottom is easy to work on. You will need beer, four or five friends who like beer, steaks, some ropes, 4X2s & flat area to do this. You push the hull backwards onto the tyres & once it it is stable drive the trailer out from under it using more tyres to support it. Then lay it over using the 4x2s & more tyres. Now you can start on the beers & the steak.. This is most important because you will need the helpers to get the hull back onto the trailer after the job is done. To recover the hull, get it upright with the bow high enough to slide the back of the trailer under it. Using a mix of winching the hull on & reversing the trailer under the hull it will come on. If you have carpet or the blue plastic on the bunks wet it to help the hull side.
I would not use acid. A random orbital sander (the model with the flexible pad) should do the job using an abrasive disk designed for use on alloy. I will not give you a specific disk as we tend to have different names for stuff down this way but a call to Pacific will get you the right info.
Start slow & work in small circles applying more pressure to stubborn areas. Use the least aggressive grit possible. When one side is finished, hose it off, flip the hull to expose the other side & repeat. As freshly worked alloy will self oxidize & "seal" itself, it needs to be kept out of the water for a while. I guess you have finished boating for the year up in the NE so there will be plenty of time for the alloy to oxidize. If you keep the boat in the water this will be an ongoing problem unless you apply anti-foul.

A good pressure washer worked great for me.

How long was the boat moored?

I second a good pressure washer. I leave mine moored, and the first year I had a lot of barnacles to remove. Now I try to pull the boat once or twice during the season for pressure washing, and that has basically eliminated my barnacle problem.

Does applying a wax on the bare alloy help at all? Capt PJ