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Affordable GPS Speedometer


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I'm looking for a SpeedPuck alternative to mount on my i14. I want to monitor live speed and export GPS tracks.

I think the SpeedPuck is quite clumsy and a lot of device for just a small number. 10+ years after it's release there surely must be some alternatives. Any recommendations?

In general I'm wondering why dinghy electronics are so expensive. Same thing with the T060. Is it just the production numbers or are the sensors so much better than what we have in smartphones?

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I think it'll be production volumes, competition, offshoring etc, lower margin distribution etc. I'd imagine that a smartphone would be $5k rather than $500 if it were made in same volume as SpeedPuck or similar.

I never fail to be amazed by how much cost can be driven out of stuff by volume and effective industrialisation.

Dan

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Have tried cheap Chinese cycling computers, cost about 15 euro each.  I sewed one to the  either side of the mainsail tack.  Could be easily attached either side of the boom. Just waterproofed with extra insulating tape. Displayed KPH, they eventually drowned and did not replace, but nice to have an easy to read speedo for a while.

Did not find just a speed number particularly useful for self coaching, or racing, compared to the gains from sailing with other similar boats.  It did cure me of wanting to spend big money on a sailing GPS.  

Still waiting for a GPS tracker or phone app to gain critical mass, like a strava for racing, for post race analytics, outside of big money tracked events.  MotionX app seems to work ok for training.

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Consider attaching a phone in a see through dry bag on the mast.  There are plenty of apps that will display your gps speed and a number of apps to record your track.  Probably the least expensive way using something you already have.

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Without a way to average speed over time, and calculate true wind speed, it seems to me that the "How many knots am I going?" is interesting but not particularly useful.

I've sailed on a number of big boats with a guy sitting there playing snacktician and monitoring speed toward the next mark, and half the stuff they rant about is useless (could be a personality issue). For tuning or training, the important inputs would be speed average over perhaps a minute, speed trend, wind speed, and wind angle. You would want to develop the best acceleration along a course at a given wind strength and angle. This is something most dinghy develop fairly well just by seat of the pants, but of course differences in boats and conditions require different targets and techniques... as far as I know, nobody makes such a thing.

There are poker chip type GPS senders that are fairly inexpensive, a couple of GPS + accelerometer could be linked to a smartphone with an app to analyze the position/speed data and perhaps even tell you things about steering habits and pitching.

FB- DSK

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A small cheap tablet computer with built in GPS would do that for  you, there are plenty of Android gps tracker programs and GPS speed meter programs. you can pick one up for around $70.

 Stick it in a plastic bag, hang it below the boom, on the mast facing you..

 

 

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57 minutes ago, maxstaylock said:

like a strava for racing, for post race analytics

For post-sailing analysis, I'm using chartedsails. No critical mass yet. I really like the analytics.

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2 hours ago, maxstaylock said:

Have tried cheap Chinese cycling computers, cost about 15 euro each.

This is a great idea. A first search on Ebay even gives some waterproof results.

2 hours ago, Steam Flyer said:

Without a way to average speed over time, and calculate true wind speed, it seems to me that the "How many knots am I going?" is interesting but not particularly useful.

I sailed with GPS speed on the 14 before and I feel it's really usefull on a boat where the speed difference between upwind modes can be so significant. And for topspeed bragging rights of course.

1 hour ago, Iceman22 said:

The Vakaros Atlas is small and had compass and GPS speed plus heel and much more.

That thing looks nice but doesn't really tick the affordable box.

With some cheap Android device I fear that readability (especially when in a bag) and battery life won't be great.

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1 hour ago, 14berlin said:

With some cheap Android device I fear that readability (especially when in a bag) and battery life won't be great.

In my experience, it's not too bad. Set the backlight to max. What's your battery life expectation? 

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7 hours ago, The Q said:

A small cheap tablet computer with built in GPS would do that for  you, there are plenty of Android gps tracker programs and GPS speed meter programs. you can pick one up for around $70.

 Stick it in a plastic bag, hang it below the boom, on the mast facing you..

I tried some early phone apps for speed, they were really inaccurate. Anything that uses change in coordinates (which I expect apps for phones and similar devices use) will likely be rubbish, things based on the GPS signal (such as SpeedPuck) are much more accurate.

My SpeedPuck is 10 years old and going strong, so there's a lot to be said for the quality. I think I got it at a special price of AUD300 so averaging that over the years means they're not that expensive.

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4 hours ago, RobG said:

I tried some early phone apps for speed, they were really inaccurate. Anything that uses change in coordinates (which I expect apps for phones and similar devices use) will likely be rubbish, things based on the GPS signal (such as SpeedPuck) are much more accurate.

My SpeedPuck is 10 years old and going strong, so there's a lot to be said for the quality. I think I got it at a special price of AUD300 so averaging that over the years means they're not that expensive.

Did I not say a tablet fitted with a GPS chip?, These are, with the right program, just as accurate as your speed puck, they do not depend on guestimations from the nearest phone mast.

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5 hours ago, The Q said:

Did I not say a tablet fitted with a GPS chip?, These are, with the right program, just as accurate as your speed puck, they do not depend on guestimations from the nearest phone mast.

I presume that any modern device that shows its location uses GPS. Trilateration from phone towers is generally only used when GPS positioning is not available or less accurate (e.g. when inside a building). It can be pretty accurate depending on the geometry of the towers and device.

As for whether you can get accurate speed from a "GPS chip", that depends on the chip. The method used to generate accurate speed from GPS signals is different to that used to determine position. The device speed with respect to the satellite may be used to help calculate the initial location estimate, but a calculated over–the–ground speed, or the data to calculate it, may not be available to external programs.

A simple test is to compare the device speed to that of a car's speedo. There should be a consistent difference between the two, the "GPS" speed should not vary any more than the car's speedo. My experience with phone apps for speed is that they can vary from second to second by ±5% or more of the actual speed.

I guess I'm saying that just because a device has GPS location capability doesn't mean it can also generate accurate speed data.

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A cheap smartwatch with gps, the ones runners use, maybe? Not sure how the data transfer works, but most show instantanious speeds and laps etc. Buy a used one. Lot's of fitness freaks out there selling perfectly fine equipment when the get the latest gadget.

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  • 2 weeks later...
17 hours ago, Tubes said:

I'm looking at the Novasail products atm, if anyone has any experience, LMK what you think about them.

Using a NOVASAIL NS 100 since several years, I can say it's a good product which provide essential information while sailing

You can make yourself a good idea with the operating manual

NS100 Operating Manual English.pdf

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On 1/14/2021 at 8:47 AM, The Q said:

A small cheap tablet computer with built in GPS would do that for  you, there are plenty of Android gps tracker programs and GPS speed meter programs. you can pick one up for around $70.

 Stick it in a plastic bag, hang it below the boom, on the mast facing you..

 

 

Yaeeah, thats what I'm looking for. Using my android phone or tablet as a speedo only. I don't need any tracking to see where I made goofs, the list would b to long. Any ideas for an app that would read low speeds with tenths? All Ive found did not have accuracy at low speeds or did include heart rate and other non applicable stuff with slow updates.

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For simple straight speed.. then....

boatspeedo from the Google play website.

Speedo only, choose, knots, kph or mph, full screen numbers.

black background , and nothing else,  so low power drain.

Its as accurate as the chip in your tablet will allow.

 

I've tried several with tracking as I like so see where I've been occasionally, all have something I like or dislike, normally the better ones have ads or want to charge you money and I'm a cheapskate.

At the moment my favourite is Boatspeed, which has count down for racing and mapping, and angle of heel which could be useful.

 

 

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  • 1 month later...

real cheap speedo only well distance and direction too but no export/import or maps

the early GPS devices both the hikers or car units will show speed distance and direction/track

they can be found at yard sales for 5 to 20 bucks hikers units have internal battery car units need 12v power but not alot

yes there are better units for marine use but they cost alot more to get a marine map on screen

but I do not think many daysailors/racers need maps

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  • 2 months later...

To navigate the traffic, I use a simple GPS. I don't need a complicated GPS, so I don't have to spend a lot of time with it. GPS lam bought on the Motorcycle GPS platform, and I was happy for a while. However, at the moment, some technical issues really bother me and confuse me in navigating the traffic. I thought about changing the GPS to avoid all these problems, but I don't know how to choose a good GPS. maybe someone knows GPS and can help me with its choice, so as not to make a mistake with GPS. I will be very grateful for a bit of help with this problem.

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