fitting the korts and shafts is the most critical part of the build with tugs for the simple fact if you get it wrong your models going to be worth its weight in scrap.
i can't tell you where the shafts are to exit so you will have to work that out with careful studying of the plan remember measure twice drill once! but in this case do it like 50 times!!
once the holes are drilled you should elongate them to allow shaft to sit right remember the hull is curved in that area.
the prop shaft should be at 90 degrees! be sure to get that right!! ( i would suggest to fit some oilers to the shafts at this point but that's personal preference)
but the first thing you should do before fitting the prop shafts is get the korts in ..
that should be a relatively simple job the plans are full size so it should be easy to get it right, once there in you can fit the shafts.. now here's the best trick you will ever hear in getting the shaft aligned so the prop dose not foul the kort...
cut a disk out of ply the exact shape of the internal diameter of the kort...
dead centre drill a hole and then fit this disk using the brass nut to the shaft, now offer up the shaft to the hull and mark the holes needed remember to keep it level and at 90 degrees so dead flat!!
drill the hole and elongate it slightly to allow some movement for alignment, keep the disk on the end and slip it into the kort nozzle. now the prop end is going to be perfect its just a matter of sealing in the shaft.
you have korts eze with your build so you able to slide the end part back to remove the shaft .. do this to remove the disk and then add the shaft support to the hull and shaft remember to leave enough room to allow the kort eze part the ability to slide back or your "xxxxx"!!!
my trick get some 5 min epoxy .. tape the shaft in place this is aided by the shaft support or 'skeg' then inside the hull pour some 5 min epoxy on the shaft and hold it in place until its set..
once its all set fit your prop and give it a spin to check that its not binding up, if its binding your able to cut the epoxy with knife to free up the shaft and try again.
if all's OK you can strengthen the shafts joint with either car body filler or some expoy resin and glass fibre or a mix of both!
sand out the extra waste and jobs done i swear its not hard but do take your time and check, re-check and do it all again!