Werner
The poly is as good as some 5min epoxy +/- maybe, but not as good as the longer setting stuff. Also the epoxy seams better at bonding to old glass, may be 2x the strength, but either is very very dependent on the surface (rough / clean / no oils) (KEEP ALL!! SILICONE and any oils "like finger prints" AWAY FROM THE BONDING AREA!!!!!!!)
The poly was made for cross linking in liq. form = will bond if liquid can surround and lock onto (into) the surface roughness when it forms a solid. This must be done in the absence of air = (edge issues; fixed by PVA +/-) the epoxy does not have the air issue but the amine blush must be washed off before adding stuff on top. But for the Laminating cover layers, Polyester is just fine Vinylester is better. Just make sure to cover the last layer with PVA (polyvinyl alcohol) to get it to gel properly = (set).
Please note: the smooth surface can work for you, as it peels from a pane of glass pretty well for making flat fiberglass parts. Please still use wax just in case there is a small chip.
I used long set west sys. but for the clamping I hung (stood up, a 2x6 straight down from the the point of the stern) Then using 1x2's or 1x4's horz. (1 each side) and clamping between the 2x6 and the hull with a pipe clamp (using the 1x2's to kept my foam in place) on the hull for hours = no problems but I did it in 70+ weather.
Jay please check under the bottom of the rudder when it is mounted (you may want to fare this area some, so it is a little more tapered?
Also I see Dave faired it so there was a sharp flow trip area (square edges) I will be interested to see how well that works, I rounded mine which may produce more drag, but I needed the water to flow in more to the center of the prop ( 13"OD 1:1) which is so small it needs all the help it can get.
SO; will you guys be up there this weekend? I may be able to make it on Sat.
Norm