As stated, you are fine to boat with those as is. If you want to do the repair I'd pull the boat out of the water. Not sure if you trailer it. On the 3/4" I might lay some fiberglass resin in there just to build it up some but it's hard to determine the depth it from the pic. You want to build it up to about an 1/8th of an inch from the surface to allow that final 1/8th for gelcoat. Or if you have plenty of gelcoat (it's much more expensive than the fiberglass epoxy) you could just lay it all in there in a few coats and be done with it. Here's a few pics of my repairs:
The first pic it was a little deep so I used some fiberglass to build it up as I was explaining. The back of the ESP the prior owner must have backed into a mooring and spidered it bad. So I ground out all of it with a dremel and re-gelcoated it. That was a lot of work. But gelcoating is easy - it's so forgiving. If you don't like it just grind it out and start over. I wish I had some finished pics on here but I was too anxious to have the boat in the water. It turned out perfect.
Edit* I just noticed you are below the waterline with those. I'd do as the guys said and patch them up with a generic gelcoat. At least you don't have to stare at it like my ESP. Then you have the option of making it pretty in the offseason. Check out spectrumcolor.com for the gelcoat - it was a dead nuts color match. And here's a link that I followed to learn how to work with the gelcoat:
http://www.fiberglass-repair.com/rshop3.html