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Old 02-11-2007, 10:02 AM   #1
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Garmin Etrex

I've got one of the above handheld GPS's which i've only ever used for speed runs, Scott (badboy) wants to borrow it for Tricky's race thats coming up but i'm not sure its any good as its not a chartplotter thingy???
Anyone know if it will be of any help??
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Old 02-11-2007, 10:07 AM   #2
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A chartplotter is of little help in a race. If you're so lost you need a map of the coastline you're racing along, you may as well retire.

My advice is, load the waypoints for each mark, and perforrm a 'Go To' for each leg. Use the rolling road screen, with the arrow showing the way.

The garmin (and most other) gps software doesn't work well for multi lap races if you try to create a route for the whole race. it will get very confused.
Use the 'Go To' feature, and it will be fine.
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Old 02-11-2007, 10:10 AM   #3
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Thanks JF, I'd best dig out the instructions then as i have no idea how to load way points.
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Old 02-11-2007, 11:30 AM   #4
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For the race, you will not need a multi lap course ( which as JF suggests the GPS's cant handle very well! )

So simply loading the waypoints, and making a route between the waypoints and following it like a rolling road will get you near to the specific turn buoys. Then - if you have your 'course chart' you can decide which way round the buoy you need to go, and then off to the next waypoint.
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Old 02-11-2007, 11:42 AM   #5
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Quote:
Originally Posted by verytricky View Post
making a route between the waypoints and following it like a rolling road will get you near
I'd steer well clear of loading a multi waypoint route for going in circles.
Just my humble opinion, but it is based on experience and understanding the logic programmed into the Garmin GPS units. I pretty much guarantee it will throw a hissy fit if you do it that way.
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Old 02-11-2007, 03:43 PM   #6
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I'd steer well clear of loading a multi waypoint route for going in circles.
Just my humble opinion, but it is based on experience and understanding the logic programmed into the Garmin GPS units. I pretty much guarantee it will throw a hissy fit if you do it that way.

We are agreeing dumbass!

I am saying that for the course, it will not be a circular route, and the waypoints/rolling road will work well for this specific event!
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Old 02-11-2007, 03:52 PM   #7
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We are agreeing dumbass!

I am saying that for the course, it will not be a circular route, and the waypoints/rolling road will work well for this specific event!

It's round the island isn't? maybe a bit egg-shaped, but still circular.

BTW, when I've explained the reason, I will graciously accept your apology for the dumbass comment.
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Old 02-11-2007, 05:16 PM   #8
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But - it is a SPIRAL, not a Circle!!

The lines dont cross.

If they crossed, then the thing would be fugged!



Why dont you answer your phone so I can insult you in person?
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Old 02-11-2007, 05:23 PM   #9
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'Ere!
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Old 02-11-2007, 05:31 PM   #10
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But - it is a SPIRAL, not a Circle!!

The lines dont cross.

If they crossed, then the thing would be fugged!



Why dont you answer your phone so I can insult you in person?

They don't have to cross......would you like me to explain...dumbass?

And, some of us have to work, i'm in a feckin conference, so I can't answer your abusive call.
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Old 02-11-2007, 06:35 PM   #11
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Yes, you have to explain, cos I thought it was only if they crossed, or passed the same point twice.
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Old 02-11-2007, 07:11 PM   #12
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Multi- Lap GPS:
Dont use the same waypoint allocate new: lat long, vary by the minimium amount for each time it comes up. Only once will it be in the actual location but pretty close on the rest unless you going for 10 laps +

depends how good the unit is as to the success,
Its a marine thing Aviation units are fine flying in circles for hours on end going around the same co-ords
Fine Example above Very Trickys pad just look up at about 0800 tomorrow morning Marc
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Old 02-11-2007, 07:33 PM   #13
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Fine Example above Very Trickys pad just look up at about 0800 tomorrow morning Marc
I have a shot gun - dont scare my chickens!!
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Old 02-11-2007, 07:34 PM   #14
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Fine Example above Very Trickys pad just look up at about 0800 tomorrow morning Marc
Hmmmmmn - O8hoo - You are safe. Wont be awake for a few hours....


1 mile west exactly, on the Greenwich Meridian exactly...
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Old 02-11-2007, 08:21 PM   #15
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It's round the island isn't? maybe a bit egg-shaped, but still circular.

.
Wouldn't tha be Ovoid ish!
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Old 02-11-2007, 10:14 PM   #16
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Yes, you have to explain, cos I thought it was only if they crossed, or passed the same point twice.
OK Dumbass.

This is of course based on my experience. I believe it to be proven, at least it was with the GPSs of the generation that was current when I raced, and for quite a while after. I have no reason to think they've changed any.

Right, the GPSs used for marine pleasure navigation (ie, pretty much all of em) have their software aranged in such a way that you can have a number of waypoints stored (usualy upwards of 250) and also a number of routes made up of waypoints in that list.

For example, you might have a route stored, made up of 20, or 30 waypoints that takes you from say, Dock Head at Southampton, to Plymouth.
In normal pleasure use, that would take you nicely from mark to mark, in the pre-programmed sequence, ending in plymouth. Perfect.

Now, there's another wee aspect to the route execution that again, for pleasure use, navigating in the normal way, from one location, to another, one way, and usually in one direction, is perfect.

Example: The route we spoke of earlier (Southampton > Plymouth) is sitting happily in the GPS memory, however, you're floating about near hurst castle (near the Needles) and have just decided to take a trip to Plymouth.
If you select your stored route to Plymouth, the software looks at your current location and automaticaly plots it's first leg, as the next waypoint in sequence, closest to where you are, and then carries on along the rest of the pre-programmed route from there on. So It kind of hops onto the route, adjacent to where ever you happen to be when you activate the route.

This is done ('thinking' just a bit too much for it's own good) because if it did exactly what it was told (which would be perfect for racing multi, or even single lap races) it would first try and take you to Dock Head to begin your route, as this is the first waypoint in your pre-programmed route, even though this is 15 miles in the wrong direction and across a large part of Hampshire. So, for pleasure navigation, this little bit of software behaviour is very clever, but for racing, it is shite, because:

Whilst mustering just off Cowes for the start of the RTI race, you call up and activate your pre-programmed route RTI, but clever Mr GPS says to itself, "Hang on a minute, you don't need to go round all those silly marks, and that big island, because your final destination is just in front of you! (or maybe behind)" and normaly, but not always, it will tell you summat daft like you have 1/2 a mile to go to the end of the race, even though you haven't actualy started yet.
Sometimes they start ok, then get confused, and throw a hissy.

We had lots of fun & games trying to get round this problem without having to touch the GPS, as this wasn't easy tearing along at 80 (as we both had jobs to do in the boat, and niether were dedicated Navis)

We ended up with 4 GPSs on the dash, with each one set on a 'GoTo' to the longest, or most hard to find & distant marks, and we'd choose the appropriate gps to follow for any particular leg, then just used our eyes, and the compass for the short, easier legs.

However, if you have a dedicated naviguesser, who can hang on to the GPS and push the buttons without too much trouble, the easy way, is as I suggested, of having all the waypoints stored, and call each one up in turn, as a 'GoTo', which is a surefire way of ensuring no confusion on the part of the GPS control software.

All this is my humble opinion, so feel free to shoot me down. (but it worked perfectly for us)
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Old 02-11-2007, 10:26 PM   #17
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The workaround I found on my gps was to go a Follow Route (or whatever the command is), and THEN do a goto waypoint for the relevant first mark of the route you want to navigate to.

In racing circumstances more hassle than it's worth, but is possible to make the fkkr do what it's told.
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Old 02-11-2007, 10:35 PM   #18
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With the garmin units, all the time the end waypoint is nearer than other waypoints in the route, it wanted to go for it (sometimes, not always)
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Old 02-11-2007, 10:41 PM   #19
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Certainly found that it did that by default, but then manually selecting the 1st mark after selecting the route it worked OK (was on Garmin). But with the size of the typical course, it aint worth bothering cos you can eyeball 1 mark to the next.

And who's gonna get lost going round the island anyway. It's not like trying to navigate to weymouth via france, is it.
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Old 02-11-2007, 10:53 PM   #20
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And who's gonna get lost going round the island anyway. It's not like trying to navigate to weymouth via france, is it.
This is true.

Is it going to be just RTI, first home wins, or are the marks being monitored, ie, it used to be Sconce, Bridge, West Princessa, Bembridge Ledge etc (West Princessa was always a bitch)
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