Guessing it would need some weight to allow it to sink a little, but also be buoyant. Maybe aerated concrete (or even normal concrete) is the answer?: https://w

Guessing it would need some weight to allow it to sink a little, but also be buoyant. Maybe aerated concrete (or even normal concrete) is the answer?: https://www.seasteading.org/wp-content/uploads/2015/12/The-Case-for-Geopolymer-Concrete-in-Seasteading-Michael-Eliot-3-2015.pdf https://www.seasteading.org/wp-content/uploads/2015/12/The-C...