Speed boat simulator in development

Forces view showing aerodynamic and hydrodynamic force vectors. This also shows a blue outline where the boat touches the water to visualize the wetted surface area of the hull. This is handy for tuning the hull shape to get it really flying.

http://www.performancesimulations.com/wp/wp-content/uploads/2015/05/boat-sim-forces-view.png

 

Can I ask you guys which engine sound you prefer? The red boat or the blue boat? Neither one is really a set of recordings from a 2-stroke outboard, but these are my only options right now so it'll have to be one or the other.

https://www.youtube.com/watch?v=sYhMNj21LBM&feature=youtu.be

 

Here's a new one from the audio guy:
http://www.youtube.com/watch?v=7hG47hpvD4A&feature=youtu.be

 

purple one for me. It would be great to get the sound to change when you cross a wake or a big wave -

you're doing some pretty cool stuff there - is the background scenery randomly generating, or is it a big map?

 

Thanks. The scenery is generated from NASA satellite radar height and image data. Basically it's like Google Earth. I then go in and dig out the rivers/lakes, add trees and buildings and so forth using another tool, so it's not totally automatic.

The red/blue boat scene is Lotus Lake in Chanhassen, MN, where I grew up. Naturally my home lake from childhood would be the first scene to do. That one's a small lake, maybe a couple miles long. The purple boat is in Glen Canyon, Utah, a few miles east of Lake Powell, and is a really huge area about 20 miles long I think. It takes a good 20 or 30 minutes to drive the whole thing in a 80-90 mph boat.

 

Can't seem to edit the original post for some reason, maybe there's a time limit on that here?

Anyway, just wanted to change it to the new website I started: http://speedboatsim.com

 

Yes, there is a 7-day edit window. I've updated the link in the first post now.

 

Thank you, sir. I appreciate it.

 

The videos are very impressive.
From the technical point of view, what is the purpose of these videos ?. What can a designer expect from this tool?, when completed, of course.

 

Qualitatively, the program seem to capture the dynamics of the planing boat pretty well. I am actually pretty impressed by the realistic looks of chine-walking, porpoising and blow-over accidents.
With some fine-tuning to meet the measured data of full-size boats, who knows - it might have a potential to become a valuable help for the analysis of a range of dynamic instabilities of planing boats at the design stage.

 

Todd,
the screenshot in the post #16 is too wide, makes the page unreadable even on a 27" monitor. Could you please resize it to more acceptable dimensions? Thanks.

 

Hi daiquiri,
It is possible that in the future the program permits study everything you say. For now it seems, rather, another game.
It would be interesting to know how you can change the model of the ship, if it's important or not having on-screen landscape Lotus Lake, if the change can happen something bad to experiment and how to verify that the ship's movements are well reproduced. I guess there are options to change the type and shapes of the boat, the type of engine, outboard or inboard position and inclination of the propeller shaft, change in position of the weights, ... anyway, how to simulate the actual conditions of boat the user is designing.
Everything is very promising but I feel impatient to know how far and how Todd wants to go.
Of course, if finally the tool allows these studies of dynamic instabilities of the planing boat, it will be awesome.

 

Thanks for the feedback, guys.

It's possible that I have the wrong audience here. I'm intending this to be more of a sim/game than a serious design tool with graphs and analysis and so forth, but if it turns out that some people find it useful for working with real boats, I could think about extending it in the future to provide details like that. The physics model is pretty robust as you can see by the dynamics, definitely not your typical video game. It might be useful as a learning tool to learn generally in a qualitative sense what various design parameters do in the high speed, planed regime of operation in a human in the loop system, but I'm not sure that I'd want to promote it as anything more than that. So for now I'm sticking with "it's a game/sim."

The main reason why is that there is a simplification that makes it not very useful for real design in the planing regime (as it's coming up on plane): The water surface here is a flat plane, there are no waves at all (the tiny waves are a graphical illusion). Most importantly there is not really a bow wave even though the boat responds at low speed like there is one. The only reason it planes as well as it does is because I came up with a very simple model that adds a single extra force at low speeds to roughly approximate a bow wave. The variables on that low speed "bow wave force" are empirical, I just tuned it to get it as close to some speed versus bow angle data I found that I could. Once the boat has planed, that fake force goes away and you're left with no trickery.

Even with that faked bow wave force, the pitch angle when planing is quite a bit lower than it is from the bow angle versus speed data I was attempting to validate the model against, so I know for sure the accuracy at speeds around planing is not good enough. Still, it's better with the fake low speed force than it is without it, so I'm leaving it in there for the time being. To really do it well would mean doing 3D CFD on the water mass itself which takes major computational power. I might do that some day, I've had success writing a similar one dimensional model for air using a compute shader, so it's something I'd like to try eventually. For now though, at higher speeds (fully planed with the boat largely airborne) the simulation might be good enough for design use once that faked bow wave force disappears. It works better than I thought it would, really.

Another problem is that there's no prop ventilation here (yet) either which is very important to a real boat, of course. I'd very much like to have that. I've tried a couple things there but nothing I've come up with so far captured it very convincingly. I'll try again at some point, I would really like the engines revs to scream up as the prop ventilates with some engine trim and jackplate settings.

So at this stage I'm not sure that I'd be comfortable promoting it as something people should be using to guide real boat design too much. I'm afraid somebody might get themselves hurt or go through a lot of expense only to find the real boat handles too differently from the simulation and end up disappointed or angry. It's one thing to spend $20 or $30 on a toy, it's quite another to purchase it thinking you can use it to design a real boat. I'm thinking now about adding a disclaimer of that nature, that this is a sophisticated toy and not meant to guide real boat design any more than Flight Simulator is meant to guide real aircraft design.

I have almost no data to validate the model against, so it'd be irresponsible of me to promote it as something more than an unusually realistic boating game with sophisticated dynamics. At least at this point. If it turns out to be useful to designers, that would be great news, but I'd rather have folks like you figure out and tell me that it's useful for design rather than me promote it as such. On the other hand, it seems to me to be running a lot more like a real boat than I expected, so maybe it'll turn out to be that way. It's too early to tell.

Daiquiri: The videos are just to show off what it does and promote it. I wasn't sure if posting it in this forum was a good idea though, this may be the wrong audience for it. As for the giant picture, I assumed the forum software would resize it like most other forums do but it obviously doesn't. The monitor size doesn't matter, the resolution on that picture is either 1920x1200 or 1920x1080, so if your monitor resolution is lower than that you won't see the whole thing. Maybe I should just delete that picture from this forum? I'm running three 24" screens here, each at 1920x1200. It's visible here, but I agree it's ridiculously huge. I figured the forum would thumbnail it so you could click it to see the full size if you wanted, but that's not the case here.

 

Nice to see that you are well aware of your limits, Todd. That's the best warranty for the seriousness of your work.
Keep up the good job.

 

Todd - I am very impressed by what you are doing, by your understanding of the physical and design issues, and by your grace in taking the time to explain it in detail. As a sim it looks thoroughly enjoyable.

there may be potential as a 'sketch' design tool: I teach (terrestrial) architecture, and have been exploring the potential for physics games (Garry's Mod) to provide the virtual equivalent of the cardboard and gluegun model for architects. As well as an intuitive and engaging interface, the potential for a modified software to offer a quick and dirty sketch model, with materials and elements performing 'correctly' is very exciting. Of course, the physics of buildings are far simpler than the fluid dynamics in boat design, but there is potential to have an impact at the early stages of design, which all the heavily marketed software in my field (autodesk et al) and hysterically hyped protocols like building information modelling just cannot address. So more powerto your elbow!