What's your mile time?

[Kaihoe]

Bill,

  Your probably right, I was trying to do the maths with kids at the playground

Headmount,

  Most of the boards ar 12'6"s  with a handful of 14"s (including me) we don't really do unlimiteds down here.  And yes it is fast, but usually the top 10 finishes in under 20 minutes, top 20 in 21 or 22. 
 
   This race Jerry Stehpensen beat JP Tobin (the NZ olypmic windsurfer) by 3secs.  Annabel Anderson placed 7th overall 

[LaPerouseBay]

Actually that's 9.9 minute miles which is pretty much 6 MPH -- more considering the run at the end. What size boards are these?

Umm, Kaihoe was correct.

1.86 miles in 18.5 minutes is a 9.6 min/mile pace...

Annabel is a pistol.      

[PonoBill]

How did you get that Larry? 18.5/1.86 = 9.946

[LaPerouseBay]

The old fashioned way, I googled it.

http://www.arkansasrunner.com/calculators/minpermile.htm

[NoahG]

PonoBill is right. 9.9/min/mile OR roughly 9:57 as calculated by that arkansas runner calculator.

Been following the forum for awhile but do not post too much.  I like this topic because I've been trying to figure out what the top guys mile pace is and set my goals to reach some of their numbers.

I believe the x-factor in computing these times, however, is the "true" distance of the course.  Even the slightest Mis-measurement of the course could completely change the mile time - or example

18.5 mins / 1.86 miles = 9.946 min/mile

Let's pretend the course is off by just .06 miles (length of a football field)

So, 18.5 mins / 1.80 miles = 10.278 min/mile

Anyway, just my thoughts.

[PonoBill]

Quite right. Virtually every course I've raced on has been inaccurately measured. GPS measurement is inaccurate because it's a summation of a lot of bits of data that vary widely. Look at a trace and you'll see what I mean. Google map stuff is an approximation of the track because most people kind of straight-line it while actual tracks (my chicken line for Maliko for example) are quite different.

It's like the old question "how long is the Coast of California", and the answer is, it depends. It's nearly infinitely long if the precision is high enough.

For most endeavors it would be trivial, but our racing takes place in a small window of low speeds. And so it's very significant.

I've been modeling the hull speed of various SUP boards, accounting for waterline and weight. As usual my data is a mess, but I'll clean it up a little and post it. Playing with physical models I think I may have hit on a strategy for race drafting that could be important. It looks like there could be a hull speed advantage for close drafting, but it's so close that cooperation would be required.

On another front, I've hit on an explanation for hull speed that most folks will find intuitive and useful. It's a little long though, so I'm going to do it as a Ke Nalu post.

[LaPerouseBay]

Thanks for the clarification Noa, I stand corrected. 

[PonoBill]

Interesting, I looked at a couple of pace calculators on the web and they all agree with Kaihoe and LPB. I wonder what that's all about? Am I missing something? There's no units conversion (60 seconds=a minute, 60 minutes=an hour) since everything is decimal to begin with and the units remain the same.

[Kaihoe]

I must be approaching geezerdom cause I really can't be bothered working out which is the right answer (I once had a dgree in maths too)

Noah is right the (inaccuracy) of course distances make a big difference, even the difference between high and low tide provides his football field in difference, although we end up running the second half as they don't move the finish.

I've given up on using GPS as it measures the distance you have personally travelled, causing runners, being blown off my the wind or what ever. You get a nice number but it doesn't provide a good comparison against the guys you compete against.

[PonoBill]

Now THAT is exactly what you don't want to do approaching Geezerdom. I'm work on my math skills every morning. Kahn academy -- the best thing ever on the internet.

The GPS error problem stems from the limited precision of a GPS coordinate. Most GPS devices calculate distance by adding up all the incremental distances traveled. Besides all the wobbling around and speed variations we do,  the device adds in the error band for each of a the relatively wide variations in velocity. you get a lot of error. Surprising that it works as well as it does.

I'm wondering if all the calculators on the web are derived from the same base formula the enables easy conversion of days/hours/minutes/seconds into decimal and likewise handles the distance differences. That might account for what appears to be a consistent error.

It might seem arrogant for me to say "all of them are wrong and I'm right" but I don't think the simple calculation distance/time = pace is erroneous.

[surf monkey]

Didn't think of the measured course on a map point A to B vs the GPS. My measured course goes up two boat channels you try to keep a strait course but 5-10 strokes per side you zig zag. So would the GPS count the zig zag measuring the A to B as a long course.

So the GPS should have the Fastest times.

[surf monkey]

OK

Changed it up today measured out a different course with no turns had a slight side wind, Used a older 45 lb Bark 18'6, 10:02 time, works out to 6 MPH. Not use to paddling the heavy board but once it's moving feels good.

[hbsteve]

I believe you can get the exact distance between two fixed markers from a nautical chart of your area.  Then you can time yourself, and calculate you average speed.  NOAA is one place to look for charts.  Because these charts are used for navigation, distances should be correct.

[pdxmike]

It would be interesting to hear from people who have both a gps and an accurately-measured course.   That's a good point about zig-zagging.  If the gps is accurate, it should give a distance longer than the measured one, unless you're going perfectly straight. Measuring your distance with a gps doesn't penalize you zigzagging. 

surf monkey--you're moving fast. 

[PonoBill]

Straight line distances are always correct. That isn't the probelm. It's the path traveled that isn't. Take a typical Maliko run. Google earth and those crazy buggahs that skim Spartans say it's 9.5 miles. For me it's almost 10.5. When I get under 10 you can tell it's a flat day.

Worse yet, we zig and zag. If your GPS was extremely accurate--that is, it measured the absolute distance traveled while it's clamped to your wrist, it would say a Maliko run was 50 or 100 miles. Or maybe a thousand. Instead it averages, and uses some very zooty algorithms to do it, because it's not simple.