The attacks on US-owned and operated ships in the Red Sea and Gulf of Aden are pushing more vessels to avoid the region.
The decisions to divert mounted as the Houthis claimed to have targeted a US-flagged commercial ship on Monday, which would be the fourth to come under fire in a little over a week.
New York-based Genco Shipping & Trading said it would avoid the region after its 55,300-dwt bulker Genco Picardy (built 2005) was hit on Wednesday last week in the Gulf of Aden and then reported drones nearby a day later.