I spent 5 hours on this saving file and yet I fall under an item net and now I can't play it anymore. Does any one know how to alter the saving file?

I believe there is no way of altering the save file.

Just rename the save file under Users\(yourname)\AppData\LocalLow\Raft\Raft\SavedGames from DEAD-whatever.rgd to whatever.rgd

Hey, check
WIN + R
APPDATA
LOCALLOW
REDBEET INTERACTIVE
Raft
Users
YOURUSER
Player

DELETE RGD_USERS and open the game, that will create a new user, you will lost all of your items but you dont will lost the save