Boat steering 2

[mingki]

Hi I am installing these motors to the backside of my boat for propulsion and also for steering using dual motor controller.

My boat is this.

The steering mechanism is like this.

The motors are all fixed on my boat and I want to steer the boat by proportionally controlling each motors rotation.
Is this feasible in reality or should I just go for normal outboard steering mechanism which is just rotating the whole outboard?
The motor is very strong. 10kW. Strong enough for decent propulsion for my boat.
but, I am not sure whether this concept is good for steering.

 

[mingki]

That's right, I need to protect the prop from debris and objects flowing with water.
To eliminate prop walk, should I rotate each motor like this to keep the boat going straight?

 

[Qcprick63]

 

[moon161]

Could you develop the mission better before detailing the boat? You might ask what someone will need to self rescue when your device comes up to them.

You might also take a look at what other people have developed for similar missions.

https://www.aliexpress.us/item/3256805099603381.html?src=google&gatewayAdapt=glo2usa

 

[mingki]

That's a good item. Thank you.
I also wanted to use some water jet but I couldn't find any manufacturer.
Do you know some water jet product out there in the market that can be applied to my project?

 

[TugboatEng]

Stick, as an operator of props nozzles, I will tell you that the nozzle turns the propeller into a vacuum that specifically targets tires. They can find a tire in any ocean and wedge it between the propeller and the nozzle. So I am going to disagree that nozzles offer protection for polluted waters.

 

[IFRs]

Is your goal to bring people supplies? To bring them a flotation device they can hang onto? To bring them a thing so they can get out of the water? To bring them a water filter, a radio, a cell phone charger? etc. A big hunk of styrofoam will float, be hard to get damaged, could have compartments with food, water, medicine. Anything battery powered could have charging ports for their phones, lights, etc. I'm seeing one or two torpedo or canoe shaped thing(s) large enough to allow a person to lie down in, made of styrofoam or balsa wood perhaps with one end hollowed out below the water line with a single motor and propeller and a rudder controlled by RC. Would probably need a fin or two up front for directional stability, possibly also RC. If two of these they could have a net between them for a person to lay in, like a small catamaran. You could take two float plane floats, or small catamaran hulls, or even just two 12" diameter aluminum hollow tubes with end caps.

https://www.homedepot.com/p/Intex-E...ars-Plus-Motor-Mount-68325EP-68624E/312935135

https://classicaccessories.com/6-roanoke-pontoon-boat-blueberry

https://www.homedepot.com/p/Intex-S...with-Aluminum-Oars-and-Pump-68380EP/312788150

 

[Stick.]

Tug: I was thinking of protection from large, submerged objects, like rocks, cars, fire hydrants, etc. Stuff that won't get sucked into a prop, but that your prop/outboard lower unit will smash into as you move along. I should have clarified that in my last post. Your debris point is a very good one, I'm just biased by how I destroyed a couple outboard motor props when I was younger (submerged rocks in low visibility water). Nozzles would probably only help with light hits anyways, so maybe not worth it once you add in the debris factor.

mingki: Jet based outboard motors do exist, but the only ones I'm aware of are too big for your application (40hp seems to be the smallest).

 

[LittleInch]

Maybe have a tube with the motor and prop inside and then surround it with foam, then lash it to another one to create a catamaran type thing?

So kind of like a torpedo, but with an inner propellor.

If the tube blocks up go in reverse for a short period to blow out the crap.

One thing missing form this is the size and weight of your battery pack. they are pretty big motors and the battery for them will be substantial and weigh quite abit so you have good reserves for when someone clings on and you need to get them back to dry land. Running out of power int he middle of a flood won't do you any good.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[mingki]

Yes, that's why I will use this waterproof case for my battery packs.

I will use 48VDC(12V battery x 4pcs) battery for each motor as below.

You are right. I have been searching for water jet but it's so hard to find one with compact size and affordable price.
They are just so expensive.
I am trying to build the boat as cheap as possible.

 

[MintJulep]

Your intentions are honorable.

However, I suggest that you spend more time researching the requirements for the mission before you build a prototype that might not be suitable.

 

[rb1957]

I think what MJ means is ... how heavy are those batteries ? and how much time on mission will you get.

do you want to rescue people (then you'll something big like those ribs you posted, and not cheap)
or do you want to distribute supplies ?
are the people in a safe location or are you saving them too ? (again, the latter choice pushes you towards a large boat)
do you need to provide protection from the weather (from the people suffering exposure) ?
how long will you supply them ?? (obviously long is "better" but costs more)

I'd talk to a local rescue unit see what they think.

"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

 

[MintJulep]

I mean a lot of things, one of them being time on mission.

A 12 volt, 7 amp-hour battery = 84 Watt-hours. You've got four batteries per motor, so 336 Watt-hours.

With a 10,000 Watt motor, you get 2 minutes at full power, then the batteries are empty.

 

[3DDave]

There are already several makers of rescue drones that provide 30-60 minutes of propelled operation.

For example:

https://www.oceanalpha.com/product-item/stretcher/

It's far easier to have one motor and pivot that for the example you have, but it doesn't seem as if the small budget you have will come anywhere close to a useful drone.

Quad and Hexcopter drones are far more effective at the low budget end. There are plenty of parts, they go much faster, they have less resistance from air than boats have from water so the power requirements are less. They can carry inflatable life-vests and can drop a small line that can be a leader for a more substantial rope. A few have been equipped with floats, but that reduces the payload and increased the drag. Even fixed wing drones can be very effective.