We’ve been using Sailwave for several years and this is the first time that a skipper has said something about the BCE not being right. I re-scored the race in another program and the last few BCE’s differ. I did the BCE for the last boat by hand and came up with 5:33:46 not 4:45 as was calc’d by Sailwave.
I am using the most recent version of Sailwave 2.19.8. I initially scored in 2.16 and then downloaded 2.19 and opened the file and re-scored to see if it would make a difference.
BCE is how much faster the boat would have had to have sailed to have been first / joint first.
So I have done a test with your figures
Using the first 2 and the last 2 boats and then adding a Test boat.
The Test boat has the same rating as the last boat but its elapsed time I entered as 4:45 quicker than the time for the last boat, and as you can see this is then the same corrected time as the first boat. So the 4:45 calculated by Sailwave is the correct value for a BCE. How did you calculate your 5:33?
We’ve been using Sailwave for several years and this is the first time that a skipper has said something about the BCE not being right. I re-scored the race in another program and the last few BCE’s differ. I did the BCE for the last boat by hand and came up with 5:33:46 not 4:45 as was calc’d by Sailwave.
I am using the most recent version of Sailwave 2.19.8. I initially scored in 2.16 and then downloaded 2.19 and opened the file and re-scored to see if it would make a difference.
If you do the math, 5:33 is the time difference between the corrected
times for the two boats. That is a traditional method of displaying
finishes and the time of boats after the 1st-place boat. BUT, with a TCF
formula such as US Portsmouth that probably isn't really the most
accurate way of displaying such information - although it may be the way
that is most readily understandable by competitors and most often used
traditionally.
The confusion is just a misunderstanding of nomenclature.
Selby - BCE stands for Back Corrected Elapsed time, meaning the elapsed
time that the competitor would need to have to tie with the 1st-place
boat. The "BCE" in Sailwave doesn't actually display that time but
rather the difference between that time and the elapsed time for the
1st-place boat. Because US Portsmouth is a time-on-time type system that
scores with a calculated TCF (time correction factor, which is
multiplied by the elapsed time to come up with the corrected time) the
"BCE" displayed by Sailwave will only be equal to the difference in
corrected times when the TCF is 1.000, meaning that the US Portsmouth
number is 100.00. Sailwave is doing what it thinks is proper, although
that might not be what you expect and are used to. You'll probably just
have to educate the sailors if you want to display that information. I
don't believe Sailwave can display the difference in corrected times,
although I could be wrong (in my area 99.9% for racing is done with
time-on-distance scoring, where the "BCE" in fact IS equal to the
difference in corrected times so the issue doesn't arise often).
Art
···
On 6/20/2016 1:34 AM, Jon Eskdale jon@sailwave.com [sailwave] wrote:
Hi Selby,
BCE is how much faster the boat would have had to have sailed to have been
first / joint first.
[image: Inline images 1]
So I have done a test with your figures
[image: Inline images 2]
Using the first 2 and the last 2 boats and then adding a Test boat.
The Test boat has the same rating as the last boat but its elapsed time I
entered as 4:45 quicker than the time for the last boat, and as you can see
this is then the same corrected time as the first boat. So the 4:45
calculated by Sailwave is the correct value for a BCE. How did you
calculate your 5:33?
We've been using Sailwave for several years and this is the first time
that a skipper has said something about the BCE not being right. I
re-scored the race in another program and the last few BCE's differ. I did
the BCE for the last boat by hand and came up with 5:33:46 not 4:45 as was
calc'd by Sailwave.
I am using the most recent version of Sailwave 2.19.8. I initially scored
in 2.16 and then downloaded 2.19 and opened the file and re-scored to see
if it would make a difference.
Thanks Art - I did actually realise where the 5:33 came from - I was just wanting Selby or any of the other readers to think about what he/they calculated - compared to the definition of BCE.
If I was the competitor the BCE would me a lot more to me than the differential in corrected times. The BCE is the time I would have needed to have been quicker by - very easy to understand - If only I had finished 45secs faster I would have come first is very easy to understand - but a differential of say 55 secs in corrected time what does that mean in reality?
If you do the math, 5:33 is the time difference between the corrected
times for the two boats. That is a traditional method of displaying
finishes and the time of boats after the 1st-place boat. BUT, with a TCF
formula such as US Portsmouth that probably isn’t really the most
accurate way of displaying such information - although it may be the way
that is most readily understandable by competitors and most often used
traditionally.
The confusion is just a misunderstanding of nomenclature.
Selby - BCE stands for Back Corrected Elapsed time, meaning the elapsed
time that the competitor would need to have to tie with the 1st-place
boat. The “BCE” in Sailwave doesn’t actually display that time but
rather the difference between that time and the elapsed time for the
1st-place boat. Because US Portsmouth is a time-on-time type system that
scores with a calculated TCF (time correction factor, which is
multiplied by the elapsed time to come up with the corrected time) the
“BCE” displayed by Sailwave will only be equal to the difference in
corrected times when the TCF is 1.000, meaning that the US Portsmouth
number is 100.00. Sailwave is doing what it thinks is proper, although
that might not be what you expect and are used to. You’ll probably just
have to educate the sailors if you want to display that information. I
don’t believe Sailwave can display the difference in corrected times,
although I could be wrong (in my area 99.9% for racing is done with
time-on-distance scoring, where the “BCE” in fact IS equal to the
difference in corrected times so the issue doesn’t arise often).
Art
On 6/20/2016 1:34 AM, Jon Eskdale jon@sailwave.com [sailwave] wrote:
Hi Selby,
BCE is how much faster the boat would have had to have sailed to have been
first / joint first.
[image: Inline images 1]
So I have done a test with your figures
[image: Inline images 2]
Using the first 2 and the last 2 boats and then adding a Test boat.
The Test boat has the same rating as the last boat but its elapsed time I
entered as 4:45 quicker than the time for the last boat, and as you can see
this is then the same corrected time as the first boat. So the 4:45
calculated by Sailwave is the correct value for a BCE. How did you
When I implemented it I did it based on “what would be the most useful number to show?” and figured the answer was: “how much faster you needed to sail, taking into account the ratings of both boats, to tie with the winner”. It later turned out that this was actually called something - BCE - or to be more correct in Sailwave’s case - BCE delta. I cannot remember what I called it originally, but I can remember considering using (what turned out to be called) BCE, but figured the sailors would then just have to do subtraction to figure out what that means relative to the winner, so did the subtraction for them. I still think it’s the most useful metric to publish and at Mubmles at leasy we’ve had many “if only I hadn’t messed up that bloody tack…” beer banters based on it
If you do the math, 5:33 is the time difference between the corrected
times for the two boats. That is a traditional method of displaying
finishes and the time of boats after the 1st-place boat. BUT, with a TCF
formula such as US Portsmouth that probably isn’t really the most
accurate way of displaying such information - although it may be the way
that is most readily understandable by competitors and most often used
traditionally.
The confusion is just a misunderstanding of nomenclature.
Selby - BCE stands for Back Corrected Elapsed time, meaning the elapsed
time that the competitor would need to have to tie with the 1st-place
boat. The “BCE” in Sailwave doesn’t actually display that time but
rather the difference between that time and the elapsed time for the
1st-place boat. Because US Portsmouth is a time-on-time type system that
scores with a calculated TCF (time correction factor, which is
multiplied by the elapsed time to come up with the corrected time) the
“BCE” displayed by Sailwave will only be equal to the difference in
corrected times when the TCF is 1.000, meaning that the US Portsmouth
number is 100.00. Sailwave is doing what it thinks is proper, although
that might not be what you expect and are used to. You’ll probably just
have to educate the sailors if you want to display that information. I
don’t believe Sailwave can display the difference in corrected times,
although I could be wrong (in my area 99.9% for racing is done with
time-on-distance scoring, where the “BCE” in fact IS equal to the
difference in corrected times so the issue doesn’t arise often).
Art
On 6/20/2016 1:34 AM, Jon Eskdale jon@sailwave.com [sailwave] wrote:
Hi Selby,
BCE is how much faster the boat would have had to have sailed to have been
first / joint first.
[image: Inline images 1]
So I have done a test with your figures
[image: Inline images 2]
Using the first 2 and the last 2 boats and then adding a Test boat.
The Test boat has the same rating as the last boat but its elapsed time I
entered as 4:45 quicker than the time for the last boat, and as you can see
this is then the same corrected time as the first boat. So the 4:45
calculated by Sailwave is the correct value for a BCE. How did you
calculate your 5:33?
We’ve been using Sailwave for several years and this is the first time
that a skipper has said something about the BCE not being right. I
re-scored the race in another program and the last few BCE’s differ. I did
the BCE for the last boat by hand and came up with 5:33:46 not 4:45 as was
calc’d by Sailwave.
I am using the most recent version of Sailwave 2.19.8. I initially scored
in 2.16 and then downloaded 2.19 and opened the file and re-scored to see
if it would make a difference.
I have taken a screen shot of your answer and will forward to the skipper who questioned Sailwave’s BCE. I will study your response and figure out how to give the skippers’ a two sentence explanation. Some are analytical and will want to understand the details, others rely on the software to do the calculations.
I am sending a screen shot of your reply to the questioning skipper. I’m sure he will have more questions, maybe this will encourage him to learn Sailwave so that he can get in the weeds on this.
