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Author Topic: Speedline Shannon Lifeboat - obtaining maximum potential from the Jet drives.  (Read 28682 times)

The Old Fart

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Sounds great. There's load of ideas coming forward so it will be interesting how many of us swap and change what we fit in light of others trials. :-)
Could be expensive  {-)

Flysky I6X 10 channel on banggood, and other sites, around £45 when on offer.
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McGherkin

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I'll be using the FLYSKY I6X transmitter with a 10 channel receiver,  only needs 4 AA batteries to power it.

one switch will change from running speed mode to maneuvering control.

running mode, left stick both throttle, right stick both directions,

maneuvering mode, left stick does port motor and direction, right stick does starboard motor and direction.

buckets and trim tabs controlled automatically.

OH and a KILLSWITCH .


That’s exactly what I’m doing with my Tamar actually. I’m also limiting throttle in manoeuvring and disabling the bow thruster in running, all through the radio. Clever stuff!
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The Old Fart

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I also have a Tamar, the bow thruster only works when motors stopped, the right stick direction then controls the thruster automatically changing over. Looking at fitting active trim tabs at the moment.
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kinmel

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There is certainly more than one solution and a well spec'd transmitter can make it all very easy, but some people don't want to use mixers etc.

There will be some thoughts about it all out shortly and then people can decide what route they want to follow.

McGerkin's "Googley Eyes" option certainly works, but is beyond my ability to control the boat with it.
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McGherkin

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Did you try it then kinmel?
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kinmel

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Did you try it then kinmel?

I did set it up on the bench and then ran through all the possibilities and it was beyond my abilities to fully manage the boat.

For example the Turnigy 9X comes with spring-loading on one stick and not the other.  In your example that stick needs to be physically held up all the time the boat is cruising and I also need to manipulate both throttles and the steering. I could not keep the throttles working closely together, perhaps others can.  Removing the spring would help and adding mixers certainly will.

Your version took us out of the box, development is about looking at all the options and refining the practicalities.

Thanks for your help, keep contributing and comment on other people's efforts.
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C-3PO

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Lots of ideas to come...

I quite like the idea of these - control pots on the end of sticks...but they are expensive!



C-3PO

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McGherkin

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I did set it up on the bench and then ran through all the possibilities and it was beyond my abilities to fully manage the boat.

For example the Turnigy 9X comes with spring-loading on one stick and not the other.  In your example that stick needs to be physically held up all the time the boat is cruising and I also need to manipulate both throttles and the steering. I could not keep the throttles working closely together, perhaps others can.  Removing the spring would help and adding mixers certainly will.

Your version took us out of the box, development is about looking at all the options and refining the practicalities.

Thanks for your help, keep contributing and comment on other people's efforts.

Ah, yes. The turnigy does come with one stick friction out of the box. It's fairly easy to sort though. (or you could take the spring off the other I suppose, but you lose the 'auto stop' when you take your hands off the controller)

You want one of these;
http://rctanksaustralia.com/store/index.php?main_page=product_info&cPath=1&products_id=1

And a spring, something like this would do;https://www.aliexpress.com/item/FRSKY-GIMBAL-SPRINGS-FOR-TARANIS-X9D-X9D-PLUS/32461969736.html


My method was purely for someone wishing not to use any mixers or anything beyond direct control, of course if you wish to use a mixer it will make things MUCH easier!
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T33cno

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This is what I mean by it could get expensive. I've been buying gear I might never use cos someone comes up with a winner  {-)  and more spending
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kinmel

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This post is to identify which transmitter controllers are used during each particular manoeuvre and to then work out how to simplify the process with mixers and add-on Modules.

For example, we spend most of our time cruising around the lake and that requires us to control 5 transmitter channels. This project will enable you to mange those channels with just 2 controllers instead of 5.

Controls.

We need a minimum of 5 channels to control the water jets.
We use “controller” here to describe any stick, switch, pot, or slider on the transmitter.

Steering.

Both nozzles are always in unison and on the real boat they work through a steering wheel.
The easiest setup is to put both nozzle servos on a “Y” harness from a single controller.

There is no steering when both motors are stopped, even if the boat is still moving.

Jet Drives.

The jet drives must be capable of operating independently, but while cruising, reversing and at Zero Speed, both jet drives must operate as if one.

At speed, a slight change in either drive’s output introduces “tank steering” and the boat will turn suddenly, no matter what the nozzle steering is doing.

The ESCs ignore transmitter commands to reverse.
 
Buckets.

The buckets must be capable of operating independently when moving sideways.


What are add-on modules?

A module sits between the radio receiver and the servos, ESCs, etc. and can cause one controller setting to manage more than one function.
They are small, cheap circuit boards and a module may contain a number of boards, or a more complex board.

A module is “fit and forget”, once correctly installed you don’t need to alter anything again.

We bring a module routine into play with a specific controller, each routine has its own.

The Scenarios.

Section 2 of the Hamilton Publication HJ362 Ri A37.pdf gives more detailed guidance of helming techniques, here we are just defining controllers. 

Note:-  These are Controller defaults when using Add-ons…..

Both buckets work on one controller and are up.
Both Throttles work in unison on one controller (centred)
Steering centred.

Forward Cruising.

Both buckets are up.
Both throttles must work in unison to avoid “tank steering”
Steering as usual.

Ideal control solution   -  Add-ons default.

The 2 sticks on one gimbal are all the controllers you need.

_____________________________________

Reversing and normal braking during forward cruising.

Close both throttles
Both buckets go down
Both throttles opened slowly until stopped, or slower speed achieved
Steering as Usual

Ideal control solution

Both buckets work on one controller and go down, or to mid-way
Both throttles work on one controller
Steering as usual

_____________________________________

Emergency Stop.

Both buckets down.
Both throttles left open
Centre the steering.

Ideal control solution -

all the above happens when a throttle is moved to the 100% down position.

_____________________________________

Zero Speed and low speed Maneuvering.

Both buckets near the midway position, where thrust is equally shared between ahead and astern. Speed is altered by slightly moving both buckets in unison
Both throttles work in unison to hold boat against tide and are not used for manoeuvring.
Steering as usual.

Ideal control solution

Both buckets work on one controller and are initially at mid-point
Both throttles work on one controller at low speed
Steering as usual

_____________________________________

Moving sideways to Port.

Port bucket is down                                              Starboard bucket is up.
Port throttle slightly faster than starboard         Starboard throttle just above idling.
Steering used to keep heading

Ideal control solution

Buckets on separate controllers - Port down and Starboard up
Throttles on separate controllers – Port faster than starboard    -   Starboard constant
Steering used to keep heading

_____________________________________

Moving sideways to Starboard.


Port bucket is up                                 Starboard bucket is down
Port throttle just above idling starboard       Starboard throttle slightly faster than port
Steering used to keep heading

Ideal control solution

Buckets on separate controllers - Port up and Starboard down
Throttles on separate controllers – Port constant    Starboard slightly faster than Port
Steering used to keep heading
                -

Next is to find out how close we can get to these theoretical Ideal control solutions.

To move the development forward, we need our micro-electronics experts and those who enjoy transmitter programming to do their thing now.

The rest of us can continue the discussion and throwing ideas into the ring.
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The Old Fart

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I'll have to print this out and see if an arduino can control as described.
2 modes: running and manuvering.
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C-3PO

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Hi Kinmel,

Spooky - I spent this evening mapping out the jet/bucket/throttle positions to see what the permutations where and then see how they could be controlled.

I will digest your post what looks like a great detailed analysis!

Be interesting to see if we came up with any differences...

I think there are 2 themes emerging of one of control "under way" and "manoeuvring on station"

C-3PO
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C-3PO

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Tried to reshape my workings into the same structure as Kinmel.

Now slightly lost the plot so will recheck tomorrow - any feedback (typos & error spotting) gratefully received.

If the system uses "add-on-modules" then as Kinmel has explained the module would sit between the RC RX and the ESC, Servos etc.

This means that we could introduce operating modes where at the flick of a switch the functions on the sticks change to reflect the mode selected.

An interesting project...



C-3PO
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Colin Bishop

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Gosh! Wasn't it simpler when you just had a prop and a rudder to worry about?

Makes you wonder about the benefits of modern technology.

Colin
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T33cno

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Gosh! Wasn't it simpler when you just had a prop and a rudder to worry about?

Makes you wonder about the benefits of modern technology.

Colin
When the genius collective come up with the end result it will be an awesome experience demonstrating one.
However if anyone were to ask me to explain how it did what ............... {-)
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C-3PO

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Kinmel has agreed to an experiment...

We are going to try and glean some operating data from his Shannon to better understand what is happening when is it on the boating lake.

This will involve mounting a small "data logger" on his boat that will record data to an SD card that can then be analysed/graphed after a sailing session.

Using a real time clock on the data logger and hopefully recording video we can get a better picture of what is happening (map data to video timeline).

We intend to capture:
  • Date & time
  • Throttle positions x 2
  • Bucket positions x 2
  • Trim tabs positions x 2
  • ESC temperature x2
  • Motor temperature x 2
  • Using an onboard GPS the speed of travel over the water
  • Using a sensor the pitch and roll of the hull
This might help unravel for example if there is a point where the motors are running faster than the water can get through the jets

On the other hand it might be a complete waste of time...

An interesting experiment
C-3PO
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T33cno

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Mind blowing thanks  %% :-)
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C-3PO

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Gosh! Wasn't it simpler when you just had a prop and a rudder to worry about?

Makes you wonder about the benefits of modern technology.

Colin

How true Colin - but if you delve into the PDF files Kinmel posted about the operating of the real Shannon it comes with some baggage!

C-3PO
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Martin (Admin)

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All sounds like ancient Chinese Firework alchemy  to me!  ;) %)
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Neil

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Gosh! Wasn't it simpler when you just had a prop and a rudder to worry about?

Makes you wonder about the benefits of modern technology.

Colin


Colin,


That's why the crew have a solid 3 weeks intensive training on simulators  and relief boats at RNLI Poole College before their boat arrives on station, and then at least 3 more weeks intensive training on the new station boat and a second relief boat at the station before the new station boat is signed off to the respective station........but, as at Fleetwood in June/July/august 2016, they had the relief and new station boat for 5 weeks working in unison to train the crew...........8 weeks intensive training in all.........and our boat was an afloat boat, so no carriage launch training either.


it'll be interesting to see how long the satellite station of ST Annes just down the coast will take, as the relief boat for carriage launch training is already at Fleetwood ready for when the SLARS Supercat comes second week in January, and apparently the station boat comes on the 28th February........when their extensive boat training begins.


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Colin Bishop

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I was being ironic really. But there is the issue that when you are in a close quarters situation in foul conditions the cox needs to be able to act instinctively to control the boat so the training is indeed absolutely vital. No arguments there.

Colin
Colin



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Neil

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I was being ironic really. But there is the issue that when you are in a close quarters situation in foul conditions the cox needs to be able to act instinctively to control the boat so the training is indeed absolutely vital. No arguments there.

Colin
Colin



I know Colin,............. but when they were doing exactly the same job in 1940 war time Britain with just two screws and one "flappy" rudder to control the old girl in force 11 storms, you then realise just what amazing skills coxs'ns had without all this modern technology at their fingertips
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Colin Bishop

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Quite agree.


As far as modelling is concerned knowing how your boat handles is worth more than all the technical gizmos, fascinating as they are.


Colin
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Neil

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Quite agree.


As far as modelling is concerned knowing how your boat handles is worth more than all the technical gizmos, fascinating as they are.


Colin


you know me Colin..............I like it simple........why I like my classic lifeboats lol........this stuff is all too technical and electric wizardry for  me, but each to their own choice.
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rnli12

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I think its great Mayhemer's share their experiences, what a great legacy for many others who enjoy the hobby  :-))

Making me feel like buying one when I finish the Mersey!
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Regards,

Rich
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