Connect to https without SSL connection

When I am at college I sometimes need to access websites such as http://draw.io (for designing networks diagrams). The only issue is I cannot go to on my own laptop (MacBook Air) since the open Wi-Fi at college does not have SSL.

Is there a way how I can access sites like this?

I have tried both Safari and Chrome but none of them work.

I have also tried using a VPN (a Google Chrome plugin) however my college have blocked them. The only way for me to use sites that require SSL is using Tor.

If you need screenshots to make it clearer I will add them tomorrow (Monday) when I am at college.

I would like to use Safari instead of Chrome Since I will have to install it again.