Bend sheet metal like shown. Drill suitable hole to mount dremel. Tap for adjustable support. Make race propellers
. http://www.modelgasboats.com/media/kunena/attachments/legacy/images/1965_DSC00876_JPGfea91b252498581abbf03a581c79fc4f
http://www.modelgasboats.com/media/kunena/attachments/legacy/images/1967_DSC00878_JPGb51c7807b0d8069e9b302ee9438c213c
http://www.modelgasboats.com/media/kunena/attachments/legacy/images/1969_DSC00879_JPG9f7e4902bc011bb4ad9deb1ded578931