Racks in use

Benefits (How this will benefit the server and game as a whole): It'd give an alternative to the rack method that is more immersive and effective (though likely more limited and expensive) and add a small but not overwhelming addition to marine defenses.
Details (Description of how you think this would work, the benefits, etc): I'd imagine there'd either be a sort of 'kit' for engineers filled with like 5-10 that you activate to start building. Or you could simply make them from a metal (or plate steel) sheet. They'd be able to take more hits than a shelf, allow projectiles to be fired over them, and block movement through them at the cost of being more expensive and taking longer to set up. (Or however you would want to do it if implemented)
For those wondering what a Czech Hedgehog is. It's a large metal obstruction used to block tanks, vehicles, large moving objects, and in general inhibit movement for anything trying to get around them including troops and will often be wrapped in barbed wire to increase effectiveness against said troops. A picture is provided below.
A Czech Hedgehog