Hi Rowen, I agree with John 👍
Unless you have your own brass foundry the best we can do is turn the hub on a lathe
the blades (making sure that they are identical form and weight
s!), cutting / milling slots into the hub and then solder - which is weakpoint Number 1! Then wonder why it runs rough and cavitates cos it's outa balance and uneven pitch😡
I suggest you leave it to the pros like Rabeosch who for about 15 bucks or so will give you a robust cast, balanced and highly polished scale or sports finished article.
Weigh up the hours you will spend fiddlin' about against the price of a decent pro job. Especially if you need two or three the same for one boat.
Only time I fiddle about is when I need small scale props for my plastic magic projects 1/72 down to 1/350! e.g. 4 for a carrier like Ark Royal or Enterprise at 1/350. There ain't nowt that small on the market.
Cheers Doug 😎