The rivets I believe are .185 and are about 7/16 long...I can re-buck them but the only ones I have found are at grainger's and they are a little over 1/4 diameter. No pop rivets will work from anything that I have seen. The other option would be to drill out ALL of the hull rivets and then use bolts, neoprene washers and 3m 5200 as additional sealant.

I really am hoping I can avoid drilling out all of the rivets.