Just put a post on my blog about this simple & easy scratch-build.
The common household item that made the whole thing possible was the cardboard "core" from an empty roll of masking tape:
(https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjjJPOQCMaFpbpvGhXqn_W5e_pWYNhcz254dnTPvf9IsBWJy__t22H8_JM9QlOEaXwTBHPB3gP-eK02DsrBbXj9wE-rZIqF1hKfCRJ6HuHZaaj7JjIHedPsdXQyj8W1gMOI7ZrImRbyeHvJbCX12dFSF0aBIVoXeKCHoDKffAuSeJb4qf824ruFl3e1Vxs-/s4032/IMG_4459.jpeg)
(https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjvwkFJLEOl3Z0wvOf5ZWyhIRTN9Mx0p9C9JUo9Q3yPUvVWASQVYpu7eJvPq33iS2LgFIUiOgaT3c2L4hzMyA79SRk3C2Syq-6SzA8mqAtXx6VbpfStAQzwxIWGO7UBKOtSQlz_DDur4LbRINX6sGOMxFJU7IeKVKiN5LrH_zH5Exy4Wh9yoZ7TPf54qkje/s4032/IMG_8607.jpeg)
(https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjAR0aGWx_wR93zKbdOno1kwjIeDdgAzaFRP8ThSanoQfnEtKV1baGpDsv29daxiYvreK9OGEr-0kMYxvBbd5YQfujpHY8ySk6UAA9TGhHFfWLBY-QExsRPkYicNdeXdqLVbLz9IukoYUNSo-qblyyNEaluaym7tZHNHn-JyihHABLb-dBZJfwzdTg5H2-P/s4032/IMG_8611.jpeg)
(https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiqwagqSo2MpS5BwGNB6ITHZTlrF8CG4hrE2ZZlKbzPtPQNJ5TCF-YqyJ7S4i5PEHUpK_ipK-eui66hGvWPbja1MwEsIktSsIsbPalPQ8ScD66Kpqu0NuNVhyphenhyphenwo60Y1yaCEnsnVQbpyevT8uyg-t-Qaq7epFDYbJrnvhIKMAYTYVsKCbkDLA7o4Zcz4Esmk/s4032/IMG_8613.jpeg)
(https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjxpFpwm5DgHlPefOVHIpWJfc68cABticNxmOf_qSTAT2dtuSHZiAt2jl5cxeduhm2QfiQwRUzJsaguhZMIfz306A6MG5jQ1pQ-ErTAcyKr7CHZG1MSNRNAiyhR0iwOhM85M8eQL34OVBU7av5yZ8UhKAIf4gkMC0HkfY5HCROUu8F9TFYUnWNxVZOaJX2b/s4032/IMG_8659.jpeg)
(https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiB_Qh1XSB53UeEdYzMepNWYpb0M4423ijE9wOhjBHwaLdTnOak8wCvujBTlyjBwK1qAg5042cRD84KvuQuMGmy8Sxjj0oTwRel7Wv2rpt6O0kf6LZ5qnf2unQDz5-MSB2zrqj5hl_Mcsfdh4kGdrGzF80yBa_ut6votPvINmaw6GTm6DQMKXEn1AxsDlwu/s4032/IMG_8668.jpeg)
That's about all you need to know to do it yourself!
...BUT if you'd like to read more about it and see some more pics of the finished model in action, I invite you to come visit my blog at the link below, and thanks in advance for your time if you choose to do so:
https://maiwandday.blogspot.com/2024/08/scratchbuild-simple-easy-28mm-water.html (https://maiwandday.blogspot.com/2024/08/scratchbuild-simple-easy-28mm-water.html)
(https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg0CDHV8EYbenVKGgzQzfgBlaPfJO0sRaX4Ne54NAZ-F63E7LH3-QHdYMP8e6oZCZtfdVaECALlIQ8SWPPDIY6ZV9XbCYcwk6_FXi1iQ8RwWOmKvQjkM6Ba5F9oYz-Ycyq3oXZYhDayou-YzyXvSSIGstX0XzAEotuCq1dPiPFJGNxmSspSwQFoQLjrFSgu/s4032/IMG_7303-1.jpeg)