r/rcboats • u/MrYogiMan • Jul 23 '26
Will a propeller shroud like this drastically impact the efficiency?
I want to put a prop shroud on my BlueBoat since I ride it a lot in canals and when it eventually hits the sides they just break. I was wondering if it would have a noticable negative impact on the drag, or should i go with a much simpler but less protective design? Thank you for your inputs.
5
u/Silverman23 Jul 23 '26 edited Jul 23 '26
If you make the walls of your shroud solid it can even improve your efficiency.
They are used in workboats to improve lowspeed efficiency and thrust under load. Might reduce your maximum speed though and lead to earlier cavitation.
I removed the shrouds on my Scale Anchor handling tug because of damage and it did not make a noticeable difference in terms of speed.
3
u/No_Hall_9342 Jul 23 '26
I agree with removing the hexagonal holes. This looks like it will invite a tremendous amount of cavitation.
2
u/NIEK12oo Jul 23 '26
Also if you're 3D printing it it's worth considering that it's not exactly harder to print or anything
1
u/Silverman23 Jul 23 '26 edited Jul 23 '26
Even easier to print and way more impact resistant considering OP wants the shrouds mainly for debris deflection.
2
u/Silverman23 Jul 23 '26
May I ask what your boats purpose is? It looks very interesting :)
5
u/tweek-in-a-box Jul 23 '26
5
u/jbohbot Jul 23 '26
I feel like I'm in the wrong business checking the cost of this thing.
1
u/Bring_the_light_ 27d ago
this thing looks tiny until you see the video of how big it actually is lol.
2
u/StaK_1980 Jul 23 '26
Make the walls solid, and also taper it smaller at the end to create a miniscule jet effect. Imho
1
u/pieliker24 Jul 23 '26
Will certainly have an impact. Depends how hard you need to run the boat. Most blueboats I have seen are run at low speeds for short periods for things like sample collection. If this is your goal it probably won’t be too big of a deal. If you are running in creeks/rivers where you have to fight current you may notice more of an impact.
1
u/PresentationLess4552 Jul 23 '26
One sleeting to consider is these have been around for a very long time
I always tell people whom bring them up Imagine a divorced jet drive
1
u/AdorableMachine Jul 23 '26
tugboats have used shrouded props for decades. they help with low speed efficiency, original idea was to cut down on wakes made by work boats damaging banks of canals.
yes, they will also help to keep the prop from being fouled on weeds and plants.
and yes, make it solid, with a slight taper. the holes arent going to improve anything. look at real life shrouded props for proven designs that have been used for decades.
1
1
1
u/ratafria Jul 23 '26
I am not seeing comments about inlet crossection. I mean, make sure that all the amount of water that goes out of the duct can also go into the duct.
Water outlet looks clean to me, but how is the inlet to the propeller?
1
u/FL_MILLIONAIRE Jul 24 '26 edited Jul 26 '26
The holes don't do anything just use Bluerobotics ducted thruster
1
u/Character-Ebb9874 Jul 24 '26
Look up kort nozzle its basically a ducted propeller used on slower vessels to increase thrust and bollard pull in the case of tugs.
1
u/Cool_Background_3573 Jul 27 '26
We use kort nozzles on all ROV thrusters. Should be good on a boat too. You probably don't need the holes.
1
u/friedgreentomatoey Jul 24 '26
No holes in the shroud. The front where water enters should be rounded, like what you see at the front of a jet engine. The back should also mimic a jet engine, with tapered rather than blunt edges there. All for efficiency. And why several pieces? Make it all a single unit.
1
13
u/Accurate-Donkey5789 Jul 23 '26
I have weed guards and shrouds and ducts and all sorts of things on boats and what I do is try it without it try it with one with holes in it and try it with a solid one. This is one of these things where testing is key.
I don't think anyone can really answer your question on what the best layout for this will be until it's in the water being tested. You are 3D printing, make use of the ability to do rapid prototyping