I agree with all of waterbearer’s advice. The Old Town Tripper is a pretty cool boat and at one time was considered one of the best whitewater/river tripping tandem canoes available. If you are not adverse to investing the time and money it may be worth repairing, Don’t worry about the gouges and scratches on the hull bottom. They are common for an old Royalex boat and will not affect performance significantly. But take a look at the rough estimates of costs below before deciding. You might possibly be able to find a used Royalex tandem in your area for the same cost that is ready to paddle.
You can get most of what you need from Sweet Composites: http://sweetcomposites.com/index.html
They sell Dynel fabric, both E and S fiberglass, colloidal silica powder, graphite powder, and G Flex epoxy. To fix that canoe is probably going to require a full 16 ounces of G Flex resin and 16 ounces of hardener. The cost for those alone is $58. Fabrics (fiberglass and Dynel) could run you another $50, especially if you use the more expensive, and much better S fiberglass instead of the cheaper and more common E fiberglass. Add another $25 for additives (silica powder and graphite) and another $50-75 for incidentals (squeege applicators, stir sticks, masking tape, disposable gloves, denatured alcohol, paper towels, sand paper, and possibly some spray paint) and you are already up to around $200 or more to repair the hull.
I would also get rid of that uncomfortable-looking stern seat and home made bow seat and center thwart. A 17 foot canoe should also have a thwart mounted midway between the stern seat and center portage yoke, and Trippers did have. So if you go that route, you are looking at 2 seats, a center portage yoke, a thwart, seat hangers, and stainless hardware for the seats, yoke, and thwart. That would be another $150-175.
Take a close look at the interior of the canoe on the side opposite the areas of stem damage. If there is evidence of damage there, or a through and through hole, I would also plan to apply a fiberglass patch on the interior of the hull. The first order of business would be to get those areas of exposed foam core filled and covered. The foam core is there to provide positive buoyancy and stiffness by increasing the thickness of the hull without as much weight as solid ABS would require. But it is not very strong. If left exposed, chunks will tend to break out and the overlying solid ABS layer will tend to delaminate around the edges. It also abrades easily and will continue to get dirtier and dirtier which could adversely affect epoxy binding.
If investing upwards of $400 and a good deal of sweat equity sounds acceptable to you, the next thing I would do is remove any obviously loose fragments of solid ABS around the areas of exposed foam core. You may not have to remove every last loose bit, but you don’t want to leave any recesses between the foam core and the solid ABS stratum that are too narrow for epoxy to penetrate. Then go around the edges of the exposed core, and bevel the edges of the remaining solid ABS layer. If you happen to have a Dremel or similar rotary tool, it can be handy for this purpose, but you can get by with sandpaper and a small sanding block. Then clean up the foam core as best you can as I described previously, and allow it to dry well before applying any epoxy.
If you need specific advice on fiberglassing (cutting fabric, wetting out and filling cloth, etc) I and others can help. A useful resource, if you have not used epoxies for fiberglassing before, is “The Epoxy Book” available as a free download at the top of this page:
http://www.systemthree.com/pages/literature
This publication is put out by System Three, a major epoxy manufacturer. Some of the information will not be pertinent to your repair job, and it tends of course to describe the use of System Three products, but much of the information is general. I would pay particular attention to the section on chemistry and to section VII, which describes bonding, filling, and fiberglassing with epoxy. West System’s G Flex epoxy is somewhat unique in that it does not require metering pumps for mixing. You can mix up batches of any size simply by mixing equal volumes of hardener and resin by eye, and you can be off by up to around 20% by volume and it will still cure, which is quite convenient. G Flex is rather viscous when mixed, however, especially in cooler ambient temperatures, so I never try to wet out more then one layer of 6 ounce/square yard fabric at one time. You can also learn quite a bit from the support page at the West System website:
http://www.westsystem.com/instruction-2/