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Title: Routing in GPSNavX (comparision GPSNavX vs MaxSea)
#1
Hi,

Yesterday I was at a life demonstration of MaxSea (Basic, with GRIB, STREAMING and ROUTING module) (costs a total of 1500 EURO).
The program looks great and seems to be intuitive, but there wasn't much that GPSNavX couldn't do.

Features I like to see in GPSNavX:
* tidal stream arrows like the GRIB data, with the possibility to have tidal or weather (GRIB) data at any point the mouse pointer points (CTRL-Weather/Stream)
* view 2 or more charts at once (like vector, raster and areal photograph) with all the waypoints and boat / routes being on every map.
* log book, which automatically saves all waypoints plus infos about changing weather conditions or wind conditions with a filter function:
if wind increase by 10 kts include it in the logbook

* but the most interessting feature was the routing module:
just plan your route with waypoints and from any point where your boat is, the ideal route is being calculated and drawn as movable vector object. This route considers tidal stream forces and directions (taken from streaming data file) as well as wind force and direction (taken from GRIB files). (Just like a navigation system in cars shows you the shortest way or fastest to reach your destination.)
Of course routing calculation is used too with MOB, where wind and streams are taken into consideration too to find back your man/woman on sea.

The presenter of MaxSea told us that other progs do this too, but don't consider streaming data.

BTW when asked why MaxSea doesn't come back to MAC computers, the answer was, when C-Map charts are being ported to MAC, MaxSea will be ported back to MAC too.

By the end of 2005/2006 MaxSea will have S57 charts.

All in all I was very impressed by the presentation, but GPSNavX nearly has all the features (except those mentioned above) but for a much lesser price.

Another topic mentioned was the vulnerability of laptops under seaweather conditions.
Most laptops today do have rigid enough harddisks which can quietly absorb some shocks. But the problem is the ventilation inside laptops (computers) which gets salty moisty air inside your computer. This humid salty air can destroy motherboards. So better would be to have small selfmade PCs without ventilations. BTW how does a Mac mini compare here?
 
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#2
The routing assumes one can sail their boat to some pre-defined performance level. Manufacturers and designers provide polars for their boats (wind speed/angle related to speed). Unfortunatley the majority of sailors cannot even come close to sailing their boats to the polars. The polars assume optimal sail configuration and condition, designed displacement, skilled driving, smooth seas, etc.

It would be interesting to work on a routing algorithm, I am not sure it would actually work in the real world where there are so many varibles

- Weather forecast N days out
- Actual sailed performance versus projected (polars)
- Sea state
Scott Dillon
Sydney Australia
North Shore 38
CYCA
 
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#3
I agree you : except for racing sailors, these kind of features are not really useful !
For leasure sailors, a full integration of electronic navigation, as ferries or merchant ships, with automatic logbook, autopilot in gps mode, and so on, is not necessery a secure way of sailing...
GPSNavX features, for the lowest coast I know, offers enough efficience to let us long hours on the deck, looking around, drink in hand :wink:
Don't you believe ?
 
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#4
cyberhusky Wrote:(snip....)
Most laptops today do have rigid enough harddisks which can quietly absorb some shocks. But the problem is the ventilation inside laptops (computers) which gets salty moisty air inside your computer. This humid salty air can destroy motherboards. So better would be to have small selfmade PCs without ventilations. BTW how does a Mac mini compare here?

I'll be using a mini on the coast of Maine this summer but only for a month, which I doubt is a fair test of this issue, but I'll keep an eye on it. If we have a foggy month, :-((, maybe I'll have more to report (I hope not....). A light coating of WD-40 might be useful prevention, but I don't think I'll crack the mini that far open (I did my own RAM upgrade).
 
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#5
GPSNavX Wrote:The routing assumes one can sail their boat to some pre-defined performance level.

The prsenter of Maxsea said that this routing module is only usefull for trip longer 70 NM. For short distances it of no importance to know the better routing.

The example he showed was just based on wind and streaming forces / directions. The calculated route is made up of one track which is broken into several waypoints where to go.
The so calculated route seemed to longer than the shortest way but as streaming and wind was considered at the different waypoints and the ETA the longer route ( a bend curve) was faster because of streaming and wind advantages!
He didn't say anything about preformance sailing.
 
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#6
Here is an example of how routing works in MaxSea.

http://comen.maxsea.fr/MaxSea/Products/F...fault.aspx
 
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#7
All routing is based on forecasting the speed of your boat.

Can you forecast the speed of your boat 3 hours out, 1 day out, 3 days out? A .25 knot difference can make a huge difference of where you will be in 48 hours.

It's an interesting tool, but applying it to real-world passages could be very challenging.
Scott Dillon
Sydney Australia
North Shore 38
CYCA
 
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#8
I tend to agree wıth most comments regardıng the real applıcabılıty of polars prıvıded by buılders: They tend to be ınflated and often do not reflect varyıng sea condıtıons, even ıf one ıs as good as , say Mıke Goldıng.
However versıon 12.5 of Maxsea provıdes for you to buıld you own polars ıe ıt wıll regıster over tıme YOUR best speed at gıven wınds speed & angles and you can dıstınguısh for sea condıtıons and the robe she ıs wearıng. These polars, truly reflectıng your boat's performance combıned wıth your stırrıng abılıtıes can be very usefull for long dıstance crossıng and ıf you want to escape from a storm already on you or comıng ın your dırectıon. You can then use the routıng modul and ask the program to avoıd wınds of more than xx knots and seas of more than yy feet.
As a sıde, you can also ask a pro to come on board for a week and compare your performance/polars wıth hıs. A better way to ımprove than match racıng.
4wıw
 
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