Sean, Montgomery 17's were built with steel punch knockouts, I believe, as ballast in the earlier models. I think they were constructed with lead ballast 1980-81 forward. Check the archives at MSOG. I hope you did not get the impression that they are built with junk metal. Small (3/16 +- in my keel) pieces of steel. I still think the 23's are lead ballast. Maybe a 23 expert will chime in shortly.? Good Luck, Gary O M-17 #316a