Discussion Modeling Boats, Ships, and Other Watercraft in Orbiter? Experiments with Hydrostatics and the Touchdown Model

[Thunder Chicken]

Not sure if the Lua module supports it, but in C++, its possible to create dedicated MFD modes for a vessel module.

This is possible in Lua as well. I am actually in the middle of trying to sort out and convert the VC and MFD modes for the Bell 222 helicopter into Lua. My interests really are with the vessel physics, and I am not particularly familiar with a lot of the visual bells and whistles capabilities like VCs and MFDs, or UMMU or UCGO or any of the other interactive stuff. More knowledge cliffs I need to climb.

As far as I can tell they did a great job getting equivalent Lua methods into the interpreter. I haven't run into a situation where there wasn't an equivalent method available in Lua for a long time. The trick is to determine what the syntax is for the Lua methods. Even with the docs in Orbiter 2024 I still find myself going to the GitHub repository as it is much easier to search that for what I need for Lua. I am considering writing up a cheat sheet with the equivalent methods as the Lua .chm files, while comprehensive, are still hard to search. A Lua equivalent to the API_Reference.pdf would be ideal, but that would take some doing.

 

[Urwumpe]

Can I wish for a cute little narrowboat? (Yes, I have watched the new Wallace & Gromit movie three times this weekend. Its fun.)

 

[Thunder Chicken]

Can I wish for a cute little narrowboat? (Yes, I have watched the new Wallace & Gromit movie three times this weekend. Its fun.)

If you can produce a mesh for one, it would be easy to code.

 

[Urwumpe]

If you can produce a mesh for one, it would be easy to code.

If it is allowed to be ugly, it should be easy enough for my skills. Flat bottom, few controls, simple direct tiller.

 

[Thunder Chicken]

If it is allowed to be ugly, it should be easy enough for my skills. Flat bottom, few controls, simple direct tiller.

Beauty is in the eye of the beholder. I can code a brick if you like.

 

[Urwumpe]

Beauty is in the eye of the beholder. I can code a brick if you like.

Well, then it will become a real english beauty.

 

[Thunder Chicken]

Can I wish for a cute little narrowboat? (Yes, I have watched the new Wallace & Gromit movie three times this weekend. Its fun.)

The attached add-on should get you started. You may wish to improve on the mesh

 

[Urwumpe]

I have this right now, as a first attempt at Blender 4.3

 

[Thunder Chicken]

I have this right now, as a first attempt at Blender 4.3

View attachment 41633

I assumed that a small Diesel engine would be suitable. If you require horses on the tow path, that'll cost you.

 

[Urwumpe]

I assumed that a small Diesel engine would be suitable. If you require horses on the tow path, that'll cost you.

Shouldn't be a problem, while the specs of those highly vary, most have a very tiny engine, around 35 hp. The speed limit is 4 mph on those canals, when passing moored ships even 2.5 mph. There are even electric boats.

Engines for Narrowboats, Wide Beams & Dutch Barges - Beta Marine Propulsion Engines

betamarine.co.uk

 

[Thunder Chicken]

Shouldn't be a problem, while the specs of those highly vary, most have a very tiny engine, around 35 hp. The speed limit is 4 mph on those canals, when passing moored ships even 2.5 mph. There are even electric boats.

Engines for Narrowboats, Wide Beams & Dutch Barges - Beta Marine Propulsion Engines

betamarine.co.uk

Then I didn't do too badly despite winging the numbers. I tuned the engine displacement to give the vessel a top speed of 7 kts at full throttle, which turns out to be about 45 hp. The sea canal near where I work has a vicious tidal current which can peak at 6 kts which rather colored my thinking about power needs. Certainly currents in a freshwater commerce canal would be nowhere near that fast.

The drag coefficient cd_z based on frontal area is 0.1 which is rather low for such a boxy ship, so I'd probably recommend increasing that value to give you a more sensible top speed according to your tastes. Setting cd_z to 0.2 gives a top speed of 5.1 kts at full power, cd_z of 0.3 gives 4.2 kts.

 

[Matias Saibene]

I love watching this whole conversation get more and more interesting and detailed as Orbiter goes from being a space flight simulator to being a simulator of... well, pretty much everything.

 

[Thunder Chicken]

I love watching this whole conversation get more and more interesting and detailed as Orbiter goes from being a space flight simulator to being a simulator of... well, pretty much everything.

Orbiter really is a lovely and accurate artificial physical universe to play in, for all sorts of things, limited only by your enthusiasm and creativity. I honestly can't remember the last time I actually flew into space (on purpose, anyway) in Orbiter. I have been having too much fun tinkering with making silly physical models of this and that. Plenty of room to do fun things.

 

[Urwumpe]

Then I didn't do too badly despite winging the numbers. I tuned the engine displacement to give the vessel a top speed of 7 kts at full throttle, which turns out to be about 45 hp. The sea canal near where I work has a vicious tidal current which can peak at 6 kts which rather colored my thinking about power needs. Certainly currents in a freshwater commerce canal would be nowhere near that fast.

These 18th century canals can actually have some pretty strong currents, so you are right with picking the stronger engine there. Such boats often also have to travel along rivers, which they can do quite fine because of their size. Its quite a diverse community in UK, some boats can even cross the Channel with some modifications.

 

[N_Molson]

I'd say the biggest challenge sailing such a boat in a canal is sidewind. Getting the sailboat out of the marina was often a stressful experience, because we had to sail between quite narrow 'streets' pontoons and ships using the outboard engine.

There were two very important factors to deal with : 1) even a low-on-the-water, sleek sailboat with a long keel like the J80 gets pushed by gentle wind gusts easily. 2) Hydrofoils (keel, rudder) have, like airfoils, a stall speed. Below that speed, the ship simply refuses to turn and drifts, usually pushed by the wind.

So the key was to sail fast enough to control the ship, while keeping in mind the max speed inside the marina was in theory 3 knots.

 

[Voyager_VI]

Oh Thunder Chicken, you're on to something great here! Resurrecting 80mileshigh SRB retrieval Vessels with the narrowboat lua script. Need to work on the properties because this is full speed, lol. But still, this is sweet