possessive case

[Clark]

Is there any difference in meaning or use between:

the sun rays and the sun's rays
the river bank and the river's bank
the ship crew and the ship's crew

[Raymott]

Is there any difference in meaning or use between:

the sun rays and the sun's rays
the river bank and the river's bank
the ship crew and the ship's crew

Generally not. But there are traditional usages.
1. could be either - or more likely "sunshine".
2. is more likely to be phrased as "the river bank", or "the riverbank".
3. is almost always "the ship's crew".

Note, the first option is often compounded to sunrays, riverbank, but NOT shipcrew.

[colloquium]

Is there any difference in meaning or use between:

the sun rays and the sun's rays
the river bank and the river's bank
the ship crew and the ship's crew

I think the periphrastic construction of such possesive phrases should be:

The rays of the sun.

The bank of the river.

The crew of the ship.

I am not a teacher.