Suggestions and questions to ships

1. Why The Ship can't use Heavy Oil as fuel?
Cargo Ships can use Heavy Oils as fuel, and The Ship is obviously more massive than Cargo Ships, so I think The Ship should be able to use Heavy Oil as fuel, but it is not available now.
2. Is relocating Cargo Ships not available?
I wanted for my cargo ships to be relocated when I have more Cargo Depots than Cargo Ships. I needed an Uranium Liner and I wanted a Sulfur Liner of mine to be dismissed from its duty. So I tried relocating my Sulfur Liner to Uranium Cargo Depot but there was no such functions.
I think the Cargo Ships should be able to choose their Cargo Depots where they serve.
3. Cargo Ships should be able to transport cargoes inside The Island.
Especially in Dragontail Isle I think the bauxite mines where are so far from the starting point are so difficult to be utilized... when the Cargo Ships can't transport the products to my main industry plants. If we can order Cargo Ships to transport them it'll be much easier.

In Update 4 there will be changes to ships, so maybe even inland shipments will be added? I would wait for U4 to see, what will be available.

It'll be good if inland shipping is able.
But I want to fuel The Ship with Heavy Oil. Why does The Ship consume only Diesel?
Diesel is used by many vehicles but Heavy Oil is only for Cargo Ships, Gas Boilers and... Flares.