Sandhamn Race series
The Sandhamn Race series is based on knowledge about conditions from real life sailing in this area and the island positions is based on sea map from reality with minor deviations. The Tide conditions are added to create more dynamics.
In many cases the start-time gives a anti clockwise turn to the Tide-current, but some races could be based on one tide only (so its wise to take attention to times of tide against the time of start).
In the Sandham series all races over race version number 10 are based on the same local; current, waves and wind, conditions. In versions (1-10) the relationships of tide, wind and waves was under development. Biggest discrepancy is a comparison between Race 1 against Race 11, with decreasing difference with increasing Race number. However the discrepancy is only very local and with very slight differences.
All Races from number 11, and higher, is based on unchanged maps. The screen dumps shows this higher version. The low land islands in middle of the map lower the wind a bit more than its should, its a mistake which will be fixed in next series, there are too many race to add changes to and it's impossible to change them with exactly the same result.
Here is a link to a 59 page PDF - with all Sandhamns Map:s Wind and Current.
DATA of the Sandhamn races - example with Force 5 setting of windspeed:
- COMMON for Wind, Waves and current: it slowly increase when stopped by land.
- Current speed up to 1.3 knots. Current speed is depending’s on the setting of force (wind speed) chosen in the Race settings.
- Current direction: Follow the lands shape. Bigger islands moving more water and more fare out from it. Some Narrow Inlets also speed up current in narrow in a logical way - look at the current maps.
- Wind speed at open sea is 100-120%. Farther off shore the winds goes up to 120%, slowly increasing.
- Wind speed in some Narrow inlets is increasing or decreasing depending on the land shape against the wind direction and it will always be a lower wind speed behind land.
- Waves, depends on land condition and normally follow the wind conditions, so waves "tells you" local wind speed conditions also...
- Tide - LOW and HIGH gives a tide from E to W, FLOOD and EBB gives a tide from SW to NE
- LEEWARD SIDE OF LAND - see also the explaining graph below:
- High land = 48% wind speed
- Middle high land = 60% wind speed
- Low land = 80% wind speed (in middle of the map it affect more by mistake = ca 60-70%, in different direction)
This is Sanhamn on a reality sea map, read more about sandhamn - link to Royal Swedish Yacht Club, KSS