Propellers...book.
I highly recommend" Model Boat Propellers", printed by Model& Allied Publications. It is a very thorough explanation of how and why they work, as well as how to size them correctly for a model, a power source, IC or electric, as well as drive system choices.
This was print in 1972, but can be found on-line
https://www.abebooks.co.uk/book-search/title/model-boat-propellers/
As well as used book sellers.
It is a bit pricey, but it is worth it.
This was print in 1972, but can be found on-line
https://www.abebooks.co.uk/book-search/title/model-boat-propellers/
As well as used book sellers.
It is a bit pricey, but it is worth it.