Before it was impossible to run a torpedo with Marangoni effect. I have found that certain torpedo design and certain propellants can produce Marangoni effect, to create thrust force, to propel torpedo.
This soap boat could become a marketing idea. Because this model boat could become promotional gift toy for children soap and shampoo products. With boat dimension less then 10 cm length, and less then 4 cm width, sufficient enough as toy size . The boat is very cheap, lightweight and easy to pack and transport together with the promoted products.
For very low cost mass production promotional gift, boat material can be easily painted by paper printing machine, and cut by paper stamping machine.
Some boat designs and chemical propellants are tested. Indefinite possibility of boat designs and propellants, not only limited with the ones described in this book. Therefore, boat performance can be upgraded in the future. Hopefully some of readers will have a better boat design and found a better propellant.