Ship Simulator

English forum => Ship Simulator Extremes => General discussions => Topic started by: Traddles on August 29, 2010, 12:25:25

Title: Speeds and distances.
Post by: Traddles on August 29, 2010, 12:25:25
I am somewhat perplexed by the notation of speeds (SOG) in knots and distances (DTW) in metres. As an experienced seafarer I have never used metres as a unit of distance, only nautical miles. ??? For close quarter manoevering by all means use metres, for example when berthing the ship to report clearance distances from for'd and aft when squeezing into a space between two other moored ships. Surely not for distances to go at sea or distances steamed. :captain: :thumbdown:
Title: Re: Speeds and distances.
Post by: Tomaten on August 29, 2010, 12:26:51
I completely agree!
Title: Re: Speeds and distances.
Post by: Traddles on August 29, 2010, 12:59:11
Whilst I am aware that the Nautical mile is now internationally a fixed distance (1.852 kilometres), the practical use of the sea mile is more often used as a measure of distance at sea, and it is still termed a nautical mile by seafarers. Thus, if using knots as a unit of speed, it were better to use the partner term nautical miles. A sea mile, for the uninitiated, is the distance subtended at the surface of the earth by an angle of 1 minute of arc at the centre of the earth. As the earth is a spheroid and not a perfect sphere it is shorter at the poles than at the equator.
Title: Re: Speeds and distances.
Post by: Aad The Pirate on August 29, 2010, 13:30:24
Whilst I am aware that the Nautical mile is now internationally a fixed distance (1.852 kilometres), the practical use of the sea mile is more often used as a measure of distance at sea, and it is still termed a nautical mile by seafarers. Thus, if using knots a a unit of speed, it were better to use the partner term nautical miles. A sea mile, for the uninitiated, is the distance subtended at the surface of the earth by an angle of 1 minute of arc at the centre of the earth. As the earth is a spheroid and not a perfect sphere it is shorter at the poles than at the equator.
You're so right 'bout this. Kind of sloppy, so to speak  :doh:
Title: Re: Speeds and distances.
Post by: risbis30 on August 29, 2010, 19:29:48
Does ony of you guys know how to work waypoints on free roaming.
Title: Re: Speeds and distances.
Post by: TNeves on August 29, 2010, 23:54:15
Does ony of you guys know how to work waypoints on free roaming.

Waypoints in SSE are used with the autopilot, not like in the SS2008. Maybe in future updates we will have this added.
Title: Re: Speeds and distances.
Post by: LucAtC on August 30, 2010, 00:14:17
Having expanded the chart full screen, you will be able to insert temporary waypoints, only existing as long the chart is full screen. Another icon activates the waypoint, which at once modifies the course of your ship to go to this next waypoint. A slider can change the speed of the simulation, restored as soon as you leave the chart.
Regards,
Luc
Title: Re: Speeds and distances.
Post by: risbis30 on August 30, 2010, 16:51:35
ohwell thanks ony way
Title: Re: Speeds and distances.
Post by: Stuart2007 on August 30, 2010, 20:42:07
Whilst I am aware that the Nautical mile is now internationally a fixed distance (1.852 kilometres), the practical use of the sea mile is more often used as a measure of distance at sea, and it is still termed a nautical mile by seafarers. Thus, if using knots as a unit of speed, it were better to use the partner term nautical miles. A sea mile, for the uninitiated, is the distance subtended at the surface of the earth by an angle of 1 minute of arc at the centre of the earth. As the earth is a spheroid and not a perfect sphere it is shorter at the poles than at the equator.

Or an easier way. Point the boat in the right sort of direction and hope for the best...  ;D
Title: Re: Speeds and distances.
Post by: IRI5HJ4CK on August 30, 2010, 20:43:36
Hahah :lol:
Title: Re: Speeds and distances.
Post by: mvsmith on September 17, 2010, 20:44:38
The DTW in the 1.2 patch is now in nautical miles, which is nice for ancient mariners, but not so useful when testing missions and you want to know when you are nearing a 30-meter trigger radius.
I suspect that may be the reason it was initially in meters.
I demand an option to have DTW in meters for testing. If I don’t get it, I shall hold my breath until I turn blue and VSTEP will be very sorry.
Title: Re: Speeds and distances.
Post by: LucAtC on September 17, 2010, 23:35:47
There is a text (http://calgary.rasc.ca/latlong.htm) worth reading about the spheroid and distances at its surface.  
In a different past, different places, everything shorter than the mile was measured in meters, and sometimes above the mile, rangefinders for instance. On European waterways, distances are measured in m or its multiples, but I am not certain for more exotic places.
Regards,
Luc
Title: Re: Speeds and distances.
Post by: marcstrat on September 18, 2010, 07:23:12
Hoy,
A very nice text of the explaination of the "Miles",thanks you for that.

For the game i like the nautical mile system better.It is used on the sea,and most of the seagoing people are used to use this.
The decimal system is not used everywere on the planet,were the lenght knowned as "Metre"is  part of.
Even when you have to dock a vessel,afther a while you get used to.
Regards
Marc
Title: Re: Speeds and distances.
Post by: Traddles on September 18, 2010, 16:03:43
It is not all that long ago that we hoary old salts used to divide up the nautical mile into Cables, and Fathoms.  ::)
A cable length being 1 tenth of a nautical mile (approximately 608 feet, and based on the length of a sailing ships anchor cable.) and a fathom being roughly 100 th of a cable (i.e. 6 feet) No messing with accuracy for us, and what is a metre anyway,  ;) something invented in Napoleons day.  :thumbdown:  
In case anyone thinks I am being serious, think again. :C
Title: Re: Speeds and distances.
Post by: Dazzle MN on October 05, 2010, 20:19:00
I must admit from a modern seafaring point of view in an industry which is drastically changing now, The Nm is a measure of distance above the water, m is a measure of depth given on the chart at the lowest, low water.
With an industry preparing to adopt the new ECDIS system over paper charts it does make things easier for VSTEP to make this more realistic, so long as they do not make the charts in damn raster format, those things are a waste of time.
It would be nice to see some Xbow on SS in the future, but I think also important to get some older vessels on as well, such as the Liner steam ships.