Hey! I'm an EPFL student in 1st year, and we are creating an amphibious vehicle which has to work with the strenght of a spring, so we decided to give him the form of a Catamaran. The thing is that it cannot overpass 1kg, so we prefer not to use aluminium. For the hulls we decided to use High Density PET (used in Kayaks), but for the sheet that keeps the 2 hulls together and supports the Spring Guidance, we wanted to use some light plastic Material (because the ship has to float) but with good flexural strengh. We thought about using Nylon 6/6, the sheet is about 4mm width. It is an appropiate material? To put the hulls and the sheet together we had to use Heli-Coils to be able to put screws in it, but i recently found Nylon Screws, if we use them do we need to put Helicoils in it, or if both materials are plastic there is no need? THANK YOU!!