I picked up on this discussion by accident. I had to chuckle. I joined the group (for a second time) to get away from the local boat club politics only to be met by two dogs trying to urinate on the same tree without wetting each other. :-D
Nevertheless, Nick, its called a SWAMBO (She who always must be obeyed).
On the scale prop issue, here's my view, and I am nowhere near experienced. I started my first scale model boat in 2017, and it was a plank on frame. She sails on Youtube in our channel. Her name is Juliana II (after my swambo who is #1).
I had a tug with a home made brass prop. I lost the tug when one of the blades broke off, jammed up between the hull and the cowl, and ripped the gearbox apart with the sudden stop. So, that T-shirt still fits.
I was actually surprized to read that 3D printed props can hold the strain. In my one speedboat, I have a 3D printed outboard. It had a 540 brushed motor and brass gears in the box. The 3D printed prop (PETG) disintegrated on its first run. I then fitted an Atura 2 blade, and this time it stripped the brass gears.
So when it comes to props, I prefer the buy before build option for 2 reasons. One - I have a few t-shirs, and 2 - I live in an apartment and my workshop is a dining room table.
Having said that, buying for me is a major issue. First of all, if you look at the flag on my profile you may notice every price is X20. And then, since most manufacturers are either in the US, EU or FE, the shipping is X100.
I once ordered a set of props. Paid $10 for it, and $150 do get it to me.
Further more...I tend to urinate on Lew's side of the tree when it comes to scale models. Sorry Mr SPQR. 😀
Forget the calculations. A Scale model runs at scale speed. I have seen scale models running so fast in search of a bow wake, it was doing Mach 7.5 if you had to scale it up to the real ship.
Scale boats are in a different class. Not even Proboat's Harbour Tug with that H on the funnel will cut it. That is a scale toy boat.😁 But that's my "humble" opinion as a scale model boater. If the model is 1:20 scale, and I put a crewman on deck at 1:20 scale, the railing must be at his belt (+/- 900mm to 1.1m) (Yes sorry, I moved on to the metric system. All I know about imperial is that their car rental sucks and a half-inch fix anything on a Ford).
Fair winds -and Stormy seas. (calm seas do not make nice slow-mo videos)

There is only one 'supreme authority' that I know of, and I'm married to it!

Obviously SPQR. I'm done with this nonsense.

Lew,
Florida, USA

Sooner or later I will learn what I should or should not write. I'm not trained well yet.

"Supreme authorities"? "Hahahaha"? Wow, another weird post.

Lew
Florida, USA

Hi Wolle, how I envy you, you are truly lucky if the supreme authorities have determined that yours is a correct comment. Amen.
Hahahaha, I'm joking.

Wolle - I think you hit the nail on the head:

"Personally, I prefer to listen to an experienced model maker and if he shows me a link to what he thinks is a good product, I am very grateful."

That is quite different from posting a list of suppliers without respect to the "good product" you stated.

That should be the goal of all participants on this forum.

Now that is a good comment on this subject. Thanks.

Lew
Florida ⛱️, USA

Great Wolle.
I really appreciate your modesty (we need more).

Thanks to this forum I know your works and the excellent way of working, for me you are an excellent naval modeller.

You used correct words that I agree with.

Hello, I see it differently. I don't necessarily think that most suppliers of various ship propellers and the like have the experience that a model maker who has been building models for decades has. The links are only intended to be a search aid and not advertising. Otherwise we will have more advertising here, not just model building links. Personally, I prefer to listen to an experienced model maker and if he shows me a link to what he thinks is a good product, I am very grateful. Let's enjoy this beautiful hobby and have respect for each other. Because even the best model builder (I'm not one of them) can still learn something new.

Roy,

Thank you for your input. I frequently watch "marktwained" on YouTube. He is a captain on one of the Mississippi River towboats and has a lot of videos posted. Everything from scenes along the river to a tour inside the boat. Many topics like turning a "tow" of 40 200 ft barges, loading, docking, radar, GPS, and a lot more. One recent video were about not only the propellers chewing up logs and stumps, but a steel channel marker (bouy).
Lew
Florida, USA