Yes, power by battery. We just submitted a final Product Design Specification (PDS) for our boat and have included the battery price in it: looking to spend up to £15 on batteries.
Now we can start sketching up concepts and doing more detailed calculations.
Our next step will be to design and fabricate the hull, which will be paramount to the projects' success.
The Kortz nozzles seem like a great idea, however after discussion with our adviser, he feels it would defeat the purpose of directional control purely from the props.
We will be controlling it via normal RC control, however we feel if we have time that control via an everyday controller such as a WiI remote would be pretty smart and not too hard to accomplish 😊 !
Thanks for all this help by the way, it's giving us a far clearer insight as to how we should go about the project 😊 !

You seem to be planning well. Power by battery? will this be free or included in the motor cost?
I can understand your preference for the hull style but you really need to calculate the turning forces involved and perhaps do a mock up to test before committing to final measurements. Motors do need to be reversible as this will provide the turning force required. Motor size will be determined by the actual hull size and shape together with prop selection. Brass 3 or 4 blades work well, I would avoid the coarse fast racing types as they will make control difficult.
The kortz nozzles are really just pieces of tube mounted on a vertical bearing which can be traversed from inside the hull, relatively easy to fit and don't need to be very close fitting for your intended use.
I had assumed normal model rc control and am not sure what is available for WiI style.
Glad you like the Eldergarth 😀

The slalom is really just to show off just how good the directional control of the boat is without the use of a rudder. The slalom course will be set by ourselves based on how well we think the boat will perform.
We had a toss-up over using a more stable option of hull (catamaran) and a more nimble hull type (single hull). We opted for the catamaran style hull as we felt the stability of the boat was more Important than the maneouverability. We saw videos of the previous years effort and felt we would like the boat to go a lot faster than theirs.
The plans so far are to have:
-Catamaran style hull
-Length of boat to be around 350-400mm
-Have two motors each connected to a prop. Motors ideally to be reversible to have much better turning action.
-To have a load bearing capability. So a small loading bay would need to be present.
-Boat to be controlled by WiI style remote if possible.
-Operating time of 15 minutes
-Operated from a distance of 7.5m

The kort nozzle idea looks great, how easy would it be to Implement into the design?
I'll have a look at the different motors on offer. We set out a budget below as follows:
-Motors £30 - £40
-Control £30 - £40
-Props £10 - £15
-Hull £10 - £20

Very Impressive pictures of the tug boat you have, looks like you spent a great amount of time on it, looks brilliant 😀 !!

Interesting conversion of the wave height - in my experience water can not be scaled!
I see the word slalom is used - does this equate to some form of race? Ie will you be competing with others on a timed basis? Manouverability and speed are not really that compatible so you catamaran would be ideal for speed but not so good at turns,
If you are allowed to use a kortz nozzle this would give good control. Even better if you were allowed to move the nozzle round the prop in a vertical axis giving very powerful direction control.
I had a Model Slipway Al Khubar tug that used two nozzles, those were fixed and used rudders as per full size. However steering was best done by controlling the motor speeds and direction. One forward and one reverse resulted in a spin on the spot. I used the same in another Tug Eldergarth 48" 1:32 scale (Mobile Marine) and this uses moveable nozzles (no actual rudder) and this also turns on the spot.
Attaching a couple of pics of the Eldergarth togive you the idea. The real boat worked the Mersey estuary for many years so would withstand the Sea State stated.
I use a couple of Smiths Fan heater motors with a large 12v SLA, twin Electronize ESC's (15amp). Mtronik do similar which may more suit your budget.
Hope this helps. Post details of your plans so others can join in the discussion. 😀

Hi, Dave, Thanks for the reply!
Here is the project outline that was given to us, hopefully this will give you a better perspective:

"This project will design, build and demonstrate a rudderless boat where directional control will be enabled through a twin-screw system. Conventional boats use a rudder to control the vehicle heading, in this project the speed of each screw will be controlled independently to alter the vehicle heading.
The boat should be entirely self-contained and able to handle scaled WMO Sea State 4 conditions. WMO Sea State 4 is a moderate swell with wave heights of 1.25 to 2.5 metres, thus if the boat is a 10th scale model it should be able to handle a swell of 12.5 ' 25 cm (this detail is open to negotiation). The boat should also be able to manoeuvre around a slalom course."

When concerning restrictions, the test tank at the University is approx 25-30m in length and approx 1.5m in width. However, it would be nice to be able to achieve a design whereby testing could take place at a bigger location (preferably the River Clyde!).

As Electrical and Mechanical students, we do not know much about the construction or the design of boats as such, so it's a challenging project but a very interesting one at that! I'm glad that I was allocated this project ahead of others such as a motorcycle, hovercraft, and helicopter.

Thanks again!

HI Alexander
Welcome to the site.
Are there any other parameters / restrictions on what you can build?
Will the boat have to navigate a straight or curved course?
What is your definition of "rudder"?
Is your catamaran to be wind or motor powered?
Foam should work well for the hull if covered in cloth and resin for strength,
Using a catamaran should allow you to achieve a degree of steering control by varying the motive power and direction on each hull.
Any further advice 😀 really depends on your answers to the above questions.
Good luck