Are you wanting it to look like professional, and brand new or do you want to just make sure it will not leak? Lots of considerations depending on the level of investment ($ and man hours) you want to put into it. Appears that you have a painted deck (light blue) and bottom (dark blue), which is over the original deck skin and gelcoat. A basic understanding of fixing that would be to sand it down to stable material, create a form using cardboard to maintain the curvature of the bow, and then add a combination (depending on how far removed the material is after sanding) fiberglass, epoxy, and the gel coat to match. Another way is to use a product from www.advancedrepair.com called marine epoxy (after sanding it down), should be easy to sculpt to the original shape of the bow, and is water tight. Then paint to match. The good thing is that the bow is pretty stable and thick, and should be easy to fix. Be prepared to spend some hours sanding to prep, and after applying whatever material you use to get the shape you want. Plenty of videos on the web to show different levels of boat repairs. I want to say that there is a Laser video restoration project I saw that had a pretty big bow repair, and it turned out fine. Good luck and post some pictures of your final finish!