Navigation help please

Saturday afternoon was pretty good.....E 6 k, switching round to S at 11 k, sunny with some cloud and 21C.
Basically, we went back and forth across the bay, and I'm trying to figure out our average speed of the last run in 11 k of wind.

We started at 45.362837/75.844388
and ended at 45.370942/75.806120
well, within 100 yards or so.
In reality, we sailed more or less due East, so if I take 75.844388 minus 75.806120
I get .038268 of Longitude, apply that to 17,600 miles (circumference at 45N per Google),
and that gives me about 1.87 miles, which we covered in just under 9 minutes.
or about 12.5 mph or 10.7 knots.

That sound about right?

_________________
2015 H16, with spin,
SOLD 1989 Hobie SX18 Sail # 1947 "In Theory..."
'Only two things are infinite, the universe, and human stupidity. But I'm not sure about the former.'

that's what i come up with.

Decimal degrees is an unusual format.

Usually the format is ddd mm.xxxxx (degrees, decimal minutes) or ddd mm' ss" (degrees, minutes, seconds)

Are your figures truly decimal degrees?

Decimal degrees? I blindly took the math off Google Maps.
The end result of the calculation seemed reasonable.

Josh (F18 NACRA) and Joaquin (Inter 20) said I should invest in a GPS
OR use RaceQS on my smart phone.

Recommendations for a GPS?
(Easy to see and use please, I wear reading glasses when at my desk).

_________________
2015 H16, with spin,
SOLD 1989 Hobie SX18 Sail # 1947 "In Theory..."
'Only two things are infinite, the universe, and human stupidity. But I'm not sure about the former.'

You do have a decent amount of north-south in your course, if you plot it. and Given how many sailor bragging rights are at stake with top speeds, you want to make sure you have the entire distance sailed!

There are a couple of easy ways to get the full distance:
1) calculate the east-west distance just like you did. Calculate the N-S distance using the fact that 1°=60' and 1' latitude= 1 nm. Then combine the 2 distances with the pythagorean theorem (the distance between the two points is the hypotenuse). This method ignores the curvature of the earth, but works well over short distances like this.
2) google "distance between coordinates" and use one of the internet tools people have written to do the detailed calculation.
3) punch both coordinates into Google Earth and use the ruler tool to measure.

All of the above methods give you 1.69nm, or about 11.3 kts.

_________________
1990 Hobie 18SX #2077

John,

not sure if you're using anything currently, but I use the following for a "GPS"

1) a waterproof phone pouch: http://www.amazon.com/gp/product/B005LN ... ge_o02_s00
2) Two (free) GPS apps:
“Speedometer Maps and Tracks” by Yadvinder Mann records top & avg speed, total distance and time, and records your track. (Hit "play" to start GPS, "pause" to stop and "record" to save)
“Sailboat GPS Tracker and Data Logger” by Ndili Technologies, Inc, records your track with metadata - you can click on any part of your track and find out what your speed and course were at that location and time. It does not explicitly tell you your max speed, average speed or distance (hence the two apps), but it does allow you to review your track overlaid on google maps and share your track online!

For example, a few weeks ago I used the first app to record a top speed of 14.17 mph, distance of 12.61 mi, avg speed of 7.03 and time of 1 hr, 47 mins, 34 seconds on one outing.
I used the second app to record the track: http://n1.ndili.com/NTechWeb/r/1IN95ZRCCA42/tracks/en (I was sailing upwind & up current. Wind speeds were 8-12 mph out of the SW)

I don't go out without starting the GPS anymore, it's too much fun seeing what my top speed was at the end of the day! I don't use it at all while sailing, but I like taking a look afterwards. I find the track interesting to review - you can see where you hit consistent geographical wind shifts, or if the wind was veering or hauling consistently. Though really, I'm just happy to see what my max/average speed is after each sail, and I'm always surprised to what my total distance is. Last weekend I covered 40 miles in four hours!

Never heard of raceQS, I'll have to check that one out!

_________________
Mike

'79 H18 standard 'Rocketman II' sail #14921 RIP
'78 H18 (unnamed) sail #14921
'08 H16 sail #114312
'97 H21SC sail #238

Hey Sabres, the data logger app isn't free ($4.99), however is gladly pay for it if it was offered on my Android. I can get it on my iPad, but don't carry it for obvious reasons. The other, "Speedometer Maps..." I cannot find for either my Android or the iPad. Is that the correct name?

Smattie, that's really unfortunate! I'm running both apps on my iPhone 6. The first, "Sailboat GPS tracker and data logger" I recall being free to download and use, but to unlock the highest resolution tracking and a few other features (not relevant to Hobie sailing) there is an optional subscription service.

The second is the top result if I search the apple App Store for "speedometer maps and tracks" or "carspeedometer".

Hi John, I have been playing with RaceQs and so far I love it! It has all of the data that a sailing buff could want.
It does all the basic GPS stuff, but if you add marks and start finish to the map after you sail, it will give you VMG, groove, distance between boats etc. The best part is if you have more than one boat using it, you can replay the track with the other boat info added to your map.
Here is one I did a while ago, I was racing a Hobie Tiger around the island on my Nacra. Skip ahead a good chunk.
http://raceqs.com/tv-beta/tv.htm#userId=1017125&updatedAt=2015-08-02T00:26:48Z&dt=2015-08-01T13:24:26-07:00..2015-08-01T15:30:32-07:00&boat=Nacra&model=F18

_________________
Todd
Hobie 21SE
Bellingham, WA

Todd, great RqceQ's, well done.
Looks like you tack better than the NACRA, however his upwind is faster.


Here is a link to last week's racing on the Ottawa River up here in Canada, out of Nepean Sailing Club...
http://raceqs.com/tv/tv.htm#userId=18053&updatedAt=2015-08-13T00:20:44Z&dt=2015-08-12T17:35:37-04:00..2015-08-12T20:19:05-04:00&boat=In%20Theory&model=F18&time=1439416359011&focus=In%20Theory&tab=match&view=follow&lat=45.368279&lon=-75.822588&tilt=1&range=3878&heading=180

This is fun stuff. Wish us luck for tonight.

cheers

_________________
2015 H16, with spin,
SOLD 1989 Hobie SX18 Sail # 1947 "In Theory..."
'Only two things are infinite, the universe, and human stupidity. But I'm not sure about the former.'

Wow, that app (RaceQs) is unreal! I had no idea that there was something like that out there, I'm definitely downloading that one!

Thanks for sharing guys, I honestly found it more fun and exciting watching the digital replays of your races and playing with the analytics than I did watching the entirety of the America's Cup!

Is RaceQs pretty common/universally used at catamaran fleet races and regattas? Or is it very much a hit or miss/localized thing? I would expect a number of people to be apprehensive about using it, or concerns that it may provide an unfair advantage, but I think it looks like an incredibly fun and useful tool! If only the "live broadcast" feature worked for mobile devices, it could even be a way to involve friends and family, and make spectating a lot more fun!

Looks like I can consolidate my "two app" system, this app tells you everything you could want to know and then some!

_________________
Mike

'79 H18 standard 'Rocketman II' sail #14921 RIP
'78 H18 (unnamed) sail #14921
'08 H16 sail #114312
'97 H21SC sail #238

Consider "Sailing Tactician Beta" for Android. Logs a gpx track you can view later. I leave the triple stack set to display Vmg to mark, speed, and 10sec average speed. I hang it from the boom in a waterproof case by lanyard with a little Velcro so it doesn't spin around on the lanyard

Dang ! No Androids here:
I'm a Blackberry guy, and happy with my new Classic.
I'll need some technical help to figure out downloads....

Frostbite on Sunday, if I can get crew, and Turkey Trot on Thanksgiving Monday, (yes, this is Canada).
Then we back the boat away for the winter.....

_________________
2015 H16, with spin,
SOLD 1989 Hobie SX18 Sail # 1947 "In Theory..."
'Only two things are infinite, the universe, and human stupidity. But I'm not sure about the former.'

I have had luck with bifocal sunglasses that I get from Amazon. They are pretty cheap, so I have a few different pairs. Also, one thing to note is that a deactivated phone can still be used for GPS, so I use a retired iPhone 4s in a waterproof pouch. The biggest issue for me is that I can barely see the screen in sunlight.