You can get this in chapter 5.
The locations of the six webs are as follows:
1) The starting blueprint room in the cupboard.
2) In the vent as you crawl throuhg.
3) In the outside box to the left of the lighthouse, where you get the lighthouse key.
4 & 5) Inside the lighthouse, at the bottom of the elevator, on the framework of the elevator.
6) At the top of the lighthouse, inside the pirate chest.
Just click on all of them to get dialogue and the achievement will pop.