I am completely new to this hobby, but I jumped in quickly, making an e-cig case/lanyardThe yarn isn't going to last thoughCould I use strips of fabric?
Usually drive steel 'pilings' thru the sand into the bed rock below, then anchor the bridge towers to those pilings.
It's the use of gigantic caissons - hollow iron boxes which you lower to the sea floor and then drive them down - then guys can get down in there and workFirst used, I think, on the Brooklyn Bridge.
I don't think you could make strips of fabric narrow enough to go through the canvasAnd if you could, they would fray away to nothing.