Let the volume of the iceberg be V. The weight of the iceberg is ρ_{i} Vg. If x is the fraction submerged, then the volume of water displaced is xV. The buoyant force is ρ_{w}xVg where r w is the density of water.

ρ_{i} V_{g} = ρ_{w}xVg

x = ρ_{i} /ρ_{w} = 0.917