LA OROYA Software, 1993. ------------------------ Document for the Yachting programme, by Stephan Scholz The programme >>> Yachting <<< is public domain. C O M M E N T S : ================= This programme intends to show the relationship between wind speed and direction, sail-boom angle and yacht heading and speed, turning this into a playable simulator game. On loading, a screen showing a circular wind graph appears: The darker blue zone shows the maximum traveling speeds for modern yachts, according to the direction the wind is coming from. The light blue area shows speeds with raised spinnaker for rear winds. Improvements on the first version: ---------------------------------- - The rather messy printed numbers for the yacht speed have now been converted into a speedometer dial, and the heading is now given by a smooth mini-scrolling compass. The dashboard now boasts the name of the programme, and the pseudonym logo "La Oroya" - taken from a mountain-town in the Andes I had always wanted to visit but never got round to. - Some calculations have been taken out of the main loop and some numbers converted into variables - scrounging milliseconds... - Also, compiling it did seem to improve things a bit, thank heavens! - The background scrolling speed has been improved, making the whole programme perform more smoothly. The culprit was that I was copying the whole background instead of a third of the strip! My sincere apologies for any hassle caused. - The race is done in three separate laps. Before starting, you can point your yacht in the desired direction, i.e. depending on the wind angle, you can choose your course by clicking on the rudder chevrons "<" or ">". Press space to start the lap. You will have to keep your space bar down a few seconds, as the routine only reads the keyboard between waves, when the horizon is up. This part also lets you quit by pressing "Q". You will win if you ve won two out of three laps, Wind direction changes a bit from lap to lap. Once you ve started the radar-scanner indicates a green dot near the buoy you should be heading for. - An ocean sound, changing with speed, adds atmosphere... If you are stealing the other s wind this sound will change into a swishing sound. If your wind is being stolen, your speedometer will tell you, and the ocean sound becomes quieter. - The creacking noises are when you move your sail or raise or lower the spinnaker. The latter now takes a few seconds - 5 creaks! - Collisions are accompanied by a violent crashing sound, and you are spun off course violently! Future versions might have a damage control. Possible improvements : ----------------------- - Instead of having an automatic competitor getting sailing speeds from a wind angle table called AUTOS in the SAILDATA procedure, one could have a version where a second computer were linked up and a second operator controlled the other ship in the same fashion as Object 0 (the viewpoint - your ship, in effect) is controlled. - One could also set up a championship routine, perhaps with different models that behaved differently under different weather conditions, and hall of fame to enter one s name. Further comments: ----------------- A mathematical co-processor would probably be a grateful additive to use with this trigonometry and decimal-places ridden programme !!! An accellerator is also convenient, giving faster screen update and smoother movement, as the processor has a lot of work with all the calculations. I have tried to keep these to a minimum, using data tables as much as possible, and I haven t included a jib (the fore-sail), or the turning effect that can be achieved by letting out or bringing in only one of the two sails. A trigonometrical drift calculation for each sail is necessary, similar to the propulsion calculation (which would have to be done for each sail too), so you can guess what will happen without an accellerator! Hence also the lack of lateral drift. Normally, depending on your speed, your true course can drift upto 5 degrees leeward of your heading with winds forward of the beam. This sideways drift could be included, but would slow down the programme and make it harder to sail than it already is. So at present the YACHTING programme supposes that your course is your heading, and this is kept constant unless you move your rudder, i.e. you have a jib that someone is attending to, thus maintaining the ship balanced and on course. This way you are spared the never-ending rudder operations necessary to keep single-sailed craft on course, or balancing the jib and the mainsail all the time. INSTRUCTIONS ON HOW TO SAIL: ---------------------------- On the starting line, choose which direction to face when you start. Take care you are not heading squarely into the wind - you won t get any speed at all! Click on the rudder chevrons "<" and ">" to rotate. Your yacht will move forward if the wind catches the sail. In the main navigation instrument in the lower center, there is a light blue line indicator in the green ring, indicating where the wind is coming from, relative to your ship. If you turn your ship, this line will turn, moving round in the green ring as the wind angle changes with respect to your ship. This line is the apparent wind, which will move forwards as you gather speed, so you will have to adjust the sail boom accordingly, to maintain optimum sail angle with respect to the wind. Inside the green circle, is a drawing of your ship. You have a boom indicator which can be moved outwards on inwards by clicking on the chevrons "^" and "v". The boom will be light blue if optimum sail efficiency is achieved, although this is not possible for very rear winds. It will be green if the wind is pushing the sail - meaning less efficiency, as no laminar flow is being achieved. Laminar flow happens happens with a wind incidence of 10 to 25 degrees on the sail, as a suction force is ceated, similar to an aircraft wing. If the boom indicator is grey, however, it means the sail is flapping loosely in the wind, and you are getting no push at all. In this case you should draw in the boom, clicking on the red "v" to the right of the instrument, until the boom slowly moves in. It may take a while to start moving if it has been out far - all that loose rope has to be collected..! If you are headed straight into the wind, i.e. the blue wind line is near the nose of your ship, taking in the boom will be to no avail, and you will have to turn the yacht right or left, clicking on the red ">" or "<" below the instrument - the yellow line is your rudder. Turning will be very sluggish indeed if you have no speed, so DON T turn into the wind without speed ! - i.e. for tacking - doing a zig-zag course for a route against the wind. Even if your boom indicates laminar flow, i.e. it is light blue, there is a certain optimum position within the 10-25 degree angle of incidence range, which is 22 degrees. Move the boom in or out just a little to get this best push! Your speed will tell you. Of course, depending on where the wind is coming from your optimum speed will vary. There are no random factors affecting wind, boom or steering. It s difficult enough without those! If your competitor is too fast for you you might like to reduce the A#*2.1 value to A#*1.7 in the SAILDATA procedure in the READ A# instruction just before the AUTOS data section. (These values give the speed for the automatic ship, based on the wind graph data table). Your own ship s speed table is different: Your speed depends on wind incidence angle on the sail - this table is SAILS data section, and is complemented by the SPINNAKER data section further on). Don t change these, as it will probably ruin your yacht s performance. Your adversary s ship and your own ship behave differently: Yours is a bit faster and sails closer to the wind, although your competitor accellerates and turns faster, and runs very well before the wind. You will find it very useful to get round the other boat on the windward side, steal the other s wind. Watch out you don t get on the leeward side - you ll lose your speed. If you are heading into the wind you can do so only at an angle. Watch your speed indicator, which is to the left of the main instrument. With a 12 knot wind your yacht (which is very efficient and fast and behaves somewhat like a catamaran even!), will sail forwards at about 8 knots with a real wind coming from the side (90 deg.) and 3 or 4 knots heading into the wind at angles of 40 or 45 degrees. The real wind angle cannot be "seen" from your yacht, only the apparent wind, which changes with your speed. Should you want to see the real wind on the wind instrument, there is a line you can use: Draw H(WW,3),H(WW,4) to H(WW,5),H(WW,6). Write this in, just below Draw H(AWA,3),H(AWA,4) to H(AWA,5),H(AWA,6) in the main loop. You may find it interesting to see how your ship s apparent wind behaves with respect to the real wind, depending on your speed. If you are sailing with rear winds, your boom should be let out as far as possible, clicking on the red "^", and you can achieve a speed of about 4 kts. without spinnaker. If you click on the little box inside the speed instrument, this will slowly raise or lower the spinnaker. The symbol in the box will tell you if it is stowed (v), raised (^) or being raised or lowered (*). The spinnaker gives you increased push for any real winds coming from anywhere behind the beam (90 to 180 degrees). If you raise the spinnaker with forward winds, this will bring you to a halt. With a spinnaker, the maximum yacht speed, just over 10 knots, will be achieved with a real wind at 135 degrees. If at 180 degrees, speed is about 6 knots. For the moment, the program has a fixed real wind speed of 12 knots but the wind direction is random. Watch out with hitting the buoys or the other ship! It will send you spinning violently off course! It may happen that the other one will hit you too, so watch out! Keep an eye on the radar-scanner. The blue dot tells you where the other ship is. You are the yellow dot. Even if you or the other boat leave the boundary of the scanner, a dot remains in the blue fringe on the margin to tell you in what direction that ship is. The red dots are the three buoys, and a little green dot near one of the buoys will indicate which buoy you should be heading for. Starting off, sail for the north buoy, which lies ahead and to the left of where you are, (the other ship will set off, so you can follow it - you are faster, and can overtake it). Sail round the north buoy, (don t collide with it), and as soon as you hear the bell, or you see the green dot on your scanner disappear from the north buoy, you can set course for the Southwest buoy, and then the East one, which is the "finish line". To keep track of the route, the programme has to detect if you ve entered an area 5000 VLU s in diameter which touches the north buoy on the north side. The west buoy also has such an area to the south west. During the race, rounding the buoy without hitting it is easy enough. IMPORTANT: If you don t enter these areas, i.e. if you give the buoy too wide a berth, the programme can t detect that you have rounded the buoy, and won t finish the race - the other ship will continue sailing past the last buoy ad-infinitum... During the race it is easy enough to round the buoys close enough without danger of hitting them. The finish "line" is an area 5000 VLU s in diameter, touching the last buoy on the south east (This is the buoy you started the race from). You can enter the finishing area from any direction south of the buoy. The program detects who is first to enter this area and will tell you if you ve won the lap - and the times you ve bumped into something. Have fun! Stephan Scholz