[HN Gopher] Sail-Trim Simulator
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       Sail-Trim Simulator
        
       Author : stass
       Score  : 66 points
       Date   : 2025-04-23 18:36 UTC (4 hours ago)
        
 (HTM) web link (simulator.atterwind.info)
 (TXT) w3m dump (simulator.atterwind.info)
        
       | zeristor wrote:
       | I guess I'm not the only person who opened the link from
       | yesterday and didn't see anything about sailing.
       | 
       | https://news.ycombinator.com/item?id=43756926
       | 
       | Thank you, you've resolved my despair.
        
       | quaestio wrote:
       | Very cool demo...
       | 
       | Most yachts have polar charts, and the speed is a function of
       | sail area, heading, wind speed and direction amongst other
       | things. Are you considering calculating estimated boat speed
       | based on given conditions and controllable variables?
        
         | stass wrote:
         | Not my demo! But I got inspired by it some time ago to build a
         | simulator for monohulls which uses a physics based VPP to
         | calculate the boat speed based on input controls like
         | mainsheet, jib sheet, travelers, backstay and so on at
         | https://www.sailrhythm.com/
         | 
         | It uses Catalina 36 Tall Rig as a base model for sailboat
         | parameters and was calibrated to match ORC-published polars for
         | it within 1-5% on both close, beam and broad reaches.
         | 
         | Mostly built it for myself to help me understand how less
         | common control affect the sail shapes, angles of attack and
         | boat heel and behavior in a visual way.
         | 
         | It's still WIP, but you might find it useful for yacht-specific
         | stuff!
        
       | stass wrote:
       | If other people are interested in sailboat physics -- this
       | resource is a goldmine of information on how sailboat and sails
       | work and physics around it:
       | https://www.onemetre.net/Design/Design.htm
        
       | philips wrote:
       | I am a lake sailer. And without landmarks or anything it is
       | impossible for me to perceive the boat as moving.
        
         | derbOac wrote:
         | Even some kind of wake or something would help.
        
         | MOARDONGZPLZ wrote:
         | I thought I was doing something wrong. It doesn't seem like
         | anything I do has any effect, but guess that's just because
         | there is no apparent effect.
        
         | reaperman wrote:
         | Eventually it made sense that boat-speed only changes the
         | "apparent wind", as it's only simulating wind-boat
         | interactions, not water-boat interactions.
        
       | m_herrlich wrote:
       | You can set the wind to 0 and the speed somehow stays at 35
       | knots, I don't know much about sailing but that can't be right
        
       | cladopa wrote:
       | A great project, but it needs some kind of grid movement and
       | rocking, foam or something so you can perceive its movement.
        
       | pomian wrote:
       | Here is a fun sailboat race simulator. It's very simple, but
       | pretty realistic especially for open ocean racing. You can use
       | their default race course, sometimes join a planned regatta, or
       | make your own. (It was great during COVID, to try racing across
       | the oceans, or around the world. It's in real time, so you might
       | not need to change anything for days If you are in the trade
       | winds, and open ocean, but then when you get closer to land,
       | things get "Western" very quickly - just like with a real boat.
       | It's called SailNavSim. (Learned about it from HN.)
       | 
       | 8bitbyte.ca
        
       | 867-5309 wrote:
       | why so heavy on the water graphics and light on the sail?
        
         | stass wrote:
         | You get water graphics for free from three.js
        
       | ge96 wrote:
       | it's hard to tell if you're moving
        
       | gitroom wrote:
       | That wake thing would've totally helped me too, felt weird not
       | seeing any movement. Glad I wasn't the only one who got thrown
       | off.
        
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       (page generated 2025-04-23 23:00 UTC)