Hi @yheyer,
The Thrusters and Motors section of our website covers all our current thruster and motor related products - we do not yet sell an M500 motor or related boat-style propeller.
If you’d like to request something like that then please fill out our requests form, so we can add your feature/product request to our internal tracking 
If there’s a product you know is in development (or out of stock) then sales-related questions should be directed to sales@bluerobotics.com, so you can get up to date information, and potentially get informed when a product you’re interested in is released/available.
From a forum search, I assume you’re referring to this post? Tony has linked to a 3D model there for the propeller. From a quick look at the other models in his printables profile, there’s also one available for the BlueBoat mount.
Blue Robotics employees are also part of the marine robotics community, so we welcome and encourage running tests of cool ideas, and sharing interesting designs, but that doesn’t mean our personal projects are officially developed or supported Blue Robotics products.
I’d recommend following the manufacturing/assembly instructions Tony has provided in his Printables pages, and if you have further questions you’re welcome to raise them in this forum, in which case hopefully somebody will have a response or idea that’s helpful to you
By the way, private messages mean the community can’t see or respond, so tend to result in slower responses than public posts. I’ve made this public so it can be engaged with and valuable to the community.