The insurance cost of shipping goods through the Red Sea has more than doubled in recent days after Yemen's Houthis attacked and sank two ships, killing at least four seafarers after months of calm, industry sources said on Thursday.The Red Sea is a critical waterway for oil and commodities but traffic has dropped sharply since Houthi attacks off Yemen's coast began in November 2023 in what the Iran-aligned group said was in solidarity with Palestinians in the Gaza war.War risk premiums have risen to around 0.7% of the value of a ship…