T500 Skid steering weight limitations on autonomous jon boat

[ArduBuilder]

Hi everyone, I am currently in the designing phase for the following for lake mapping projects and to have a large open platform for testing other sensors;

10 foot (90lbs) Jon Boat
ArduRover (boat) hardware setup
2x (24v) Battleborn 100 amp batts (70 lbs total)
Lowrance sonar (going to use ReefMaster for Bathy and sidescan mapping)

My desire is to use 2x T500 thrusters mounted on the aft (approx 50 inches apart) and to use skid steering for maneuvering.

My question is whether the available thrust will be enough for the turns on the mow-the-lawn style courses (without needed to max the thrusters at 100% during the entire turn). Ideally I would like them to average in the 50% or lower during these turns and be capable of successfully making the turn.

High speeds are not needed.
When there is a body onboard, I estimate the max overall weight will be 350 lbs.

I am only familiar with the rule-of-thumb for trolling motors (2 lbs of thrust needed for every 100lbs). So for forward propulsion, I feel confident two T500s will be great. However, I am unsure how to calculate differential (skid) thrust needs based on weight and displacement values.

Any guidance you can point me towards will be greatly appreciated.

Thanks,

Mike

[EliotBR (Eliot)]

Hi @ArduBuilder, welcome to the forum

@ArduBuilder

My question is whether the available thrust will be enough for the turns on the mow-the-lawn style courses (without needed to max the thrusters at 100% during the entire turn). Ideally I would like them to average in the 50% or lower during these turns and be capable of successfully making the turn.

High speeds are not needed.

I’ll preface this with “I don’t have much experience controlling boats”, but in theory if you don’t have a particular speed requirement (i.e. you have infinite time) then any amount of thrust should theoretically be “enough” to turn your boat (at least in still water). I’m not really sure what you’re asking here.

@ArduBuilder

ArduRover (boat) hardware setup
…
When there is a body onboard, I estimate the max overall weight will be 350 lbs.

@EliotBR

As a note on this, ArduPilot’s Developer Code of Conduct specifies that:

ArduPilot is NOT certified for use in applications where ArduPilot is effectively in control of human lives. Members of the development team must not knowingly assist in projects where ArduPilot will be in control of human lives. “In control of human lives” includes but isn’t limited to manned aircraft.

Accordingly, if there is supposed to be a person on your boat and you’re planning to use an ArduPilot firmware to control it then anyone involved with ArduPilot development (including Blue Robotics staff) cannot help you.

[ArduBuilder]

Thanks so much for your response. I did not know about the “human lives” assistance limitation, but completely understand due to the liability. We will remember this for any future help requests.