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PostPosted: Thu Jul 05, 2007 1:05 pm 
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Site Rank - Old Salt

Joined: Fri Mar 23, 2007 8:12 am
Posts: 433
Location: Florida
Speed numbers & stats for all you current or future Island owners

First, I have had the Island since Oct. 06, my wife has one also.
My total number of sailing miles is over 1,000 so far, but I only started keeping a detailed log starting this year. So I will only use that data.

In 6 months I have used the Island in sail mode for 699 miles, 42 outings, 190 hours. That is a lot of use no matter how you count it. This does not include use in "Adventure kayak" mode - as those are separate numbers.

My average outing is 4hours 31 minutes, average trip almost 16 miles. Some of my longest trips have been over 26miles and over 6 hours.

Included in spreadsheet log are max speeds (GPS) and max winds speeds(online wind data recorder) for that day. If I total up all my max speeds and average them out I get 9.5mph max speed.

I started to notice a pattern.
Here are a few data points
Max boat speed mph / max wind speed mph

9.2 / 15
10.4 / 17
12.7 / 21
10.5 / 18

I noticed that the max boat speed is roughly 60 % of the max wind speed for the day (9.2mph max boat speed divided by max wind speed 15mph = .613 or 61%

So, using the spreadsheet and 42 sailing trips I found that the Island max speed works out to 66.73% of wind speed.

Like any curve this ratio won't work in very low wind speeds or very high wind speeds. My average max wind speed was 14.24 mph. Things like current, pedaling, changing wind speed, sail trim, & chop will all greatly alter performance and speed. But with 6 months of data on 42 trips I think I have developed a decent yardstick. More data tends to eliminate the occasional "bad sailing day".

Average speed for me if hard to gauge. On most trips I will stop frequently to fish, eat, sight see, ect. So when time and distance of entire trip are computed the average speed is low.
I have very easily logged many runs of over an hour where average speed was 5-6mph range.

Yakaholic


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PostPosted: Thu Jul 05, 2007 7:45 pm 
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Joined: Sat Nov 12, 2005 10:46 pm
Posts: 2424
Location: Escondido
That's some really nice info! I've heard speculation on the wind speed / boat speed ratios but yours is the first actual data I've seen. Great job!

I don't log any sailing info for the most part, but do record certain pedaling distances and speeds, since I do quite a bit of that. It really makes a nice reference base so if you want to try something different, you have a good way to evaluate your efforts.


This is apparent wind speed? What are your general impressions about speed at different points of sail? Where do you typically pick up your maximum? It seems I get my best steady speeds on a close / beam reach (in light chop), but my max speeds come in if I bear off a bit when a gust comes along. With more chop, I seem to do better on a broad reach, but then a GPS makes a poor substitute foe a sailing partner! 8)


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PostPosted: Thu Jul 05, 2007 8:27 pm 
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Site Rank - Old Salt

Joined: Fri Mar 23, 2007 8:12 am
Posts: 433
Location: Florida
Thanks Roadrunner.

The wind data come from recorders that display their data online every hour for that day and historical data.

So if I sail from 8am to 1pm I can go back in the evening and check what kind of wind I was actually sailing in.
IE
time - mph
8am E8
9am E10
10am ENE10
12pm E12
1pm E12 G14

I would then enter wind data into 2 cells
one being wind for the trip E8-14mph
The other being max wind = 14mph
Plus all the other trip, time, tides, max speed etc in other cells.

Now my max speed run might have been 9.5 mph and it might have occured at noon with a 12mph wind. But for simplicity (and symmetry) I use max GPS speed reached combined with top wind recorded for the trip. Figured by using both maximums I would get a more accurate boat speed to wind speed ratio. Most max boat speeds happen during gusts and highest winds of the day.

My sustained speed seem to happen with close reach. My fastest speeds are the gusts that happen during a broad reach - where the boat just wants to fly before the wind.

I think 66% is decent for a sailing kayak. Its not the 2x wind speed (200%) of a trifoiler. But it still promises a thrilling ride in moderate winds.

Yakaholic.


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PostPosted: Thu Jul 05, 2007 8:40 pm 
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Joined: Thu Jul 27, 2006 4:50 pm
Posts: 461
Location: sacramento california
Hey Yak- :wink:
Thanks for the rundown on the A.I..
My buddy and I took his H-16 out today in the delta and the Sherman Island bouy marker #14 max wind speed was 13mph and the max G.P.S. speed we recorded was 16.4..Just FYI for comparison on a Hobie 16 while sailing on a close reach in light air.
Kepnutz


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PostPosted: Sun Jul 22, 2007 7:27 am 
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Site Rank - Captain

Joined: Sun Jun 24, 2007 6:47 pm
Posts: 94
I took the AI on Lake Michigan the last two days with my GPS mounted.

Wind speed was on the order of around 13 knots. Sailing close hauled would get me 5-6 mph. Max speed was 8.1 mph.


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