Places to lay up the yacht in the Northern Indian Ocean

[Natali]

Hi. My intended itinerary: Malaysia (departure mid February) - Sri Lanka - Maldives (?) - Chagos - Mauritius - Madagascar (Nosy Be).

Unfortunately, I have to fly home in early May and I have to decide where to lay up a yacht in the Northen Indian Ocean.

I hope to be in Sri Lanka in March with intend to leave the island in late March. Where to go next? Tanzania wold be the best option but in this case it is a rush and well of the route.
Are the marinas in the Maldives extremely expensive?