As far as durability is concerned, the best would be a true or linear polyurethane, like Awlgrip or Sterling, just below that would be an acrylic urethane like single stage auto paints, the enamels would be at the bottom, imo. They will all look good on that boat in white, just some will last longer, and each has its benefits and drawbacks.
Awlgrip and Sterling are tough as nails when cured, but its a little unwieldy to spray, and shouldn't be cut or buffed, waxed ect....so it goes on as sprayed so to speak.
Acrylics like PPG Concept, Dupont Fullthane, Awlcraft 2000, ect are easier to apply, and can be color sanded to a mirror finish if you get some peel or runs...
Enamels like Rustoleum, tractor paints, ect are also easy to apply, and are easily repaired, but require more frequent recoating.
Personally, I like acrylics..
My procedure for acrylic would be:
Wash the hull completely with dawn dish soap and warm water.
Wipe the whole hull down with a wax and grease remover, using the 2 rag method.
Sand with the grit recommended by the paint system you choose.
Blow it off and wipe it again.
prime it with an epoxy primer
fair any dents or dings with an epoxy fairing compound.
Seal it with more epoxy primer.
Then spray the topcoat.
There are other methods of preparing the aluminum, like using an etching and build primer, or Alodyne and alumiprep,or a wash primer, but the epoxy primer method is easy.
Be sure to follow the tech sheet with the paint system you choose, and try to use compatible products, same system primer/paint, and catalyst.
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