Excel calculator for measuring volume and displacement with a cup or bucket

It's easy to measure the volume of a fluid sample or the volumetric displacement of an irregularly-shaped object if you have access to a "graduated cylinder" of the appropriate size. Unfortunately, graduated cylinders, especially big ones, are hard to come by. Measuring cups for cooking can work for small amounts of liquid and small dunked-objects, but they're usually not marked in fine enough increments to provide scientific precision.

Other mundane vessels such as cups and buckets can be used to measure displacement pretty well if you don't mind doing a little extra math and measurement. The purpose of this post is to simplify that math and share a tool that will do it for you. At the end of the post I share a story of how a student and I applied this technique to answer an ecological question. 

The Math Part: There's a formula for the volume of a cylinder (V = πr²h) that makes it easy to relate fluid volume to the level of fluid in a cylindrical container. In the formula, r is the radius of the cylinder and h is the height. Most cups and buckets are not true cylinders, though. They're usually wider at the top than at the base, so technically they are a truncated cone or "frustum" shape. The formula for the volume of a frustum is V = (1/3)π(R²+Rr+r²)h where R is the bigger radius of the top and r is the smaller radius of the bottom. Another thing that's tricky about a frustum compared to a true cylinder is that its vertical height (h) is shorter than the length along the wall (w), which complicates measurement. Luckily, the relationship between h and w can be calculated by substituting the relevant measures into the Pythagorean theorem for right triangles, a² + b² = c² -> (R-r)² + h² = w² then solving for h.

The Practical Approach: Follow this step by step guide and use the Microsoft Excel calculator tool embedded and linked below to turning a frustum shaped cup or bucket into a useful measuring container. The calculator file has two worksheets- "Template" is a blank version with no measurements added yet, and "Example" is filled out already with approximate dimensions of a hardware store bucket. 

Step 1) Measure the inner diameter at the wider (top) of the vessel, which we'll call "D." Half that diameter will give us the radius of the top of the vessel, "R." If you enter the value for D the calculator will fill in the value for R. 

Step 2) Measure the inner diameter of the bottom of the vessel, which we'll call "d". You might have to measure the outer diameter of the bottom of the vessel and subtract 2x the wall thickness to get the inner diameter. Half of d will give us the radius of the inside bottom of the vessel, "r." If you enter the value for d the calculator will fill in the value for r. 

Step 3) Measure the inside wall length from top to bottom, which we'll call "W." Enter that in the calculator. The calculator will now give you the total volume of the vessel in cubic mm, cubic cm, and liters. You can tweak the file if you need volume expressed in different units. 

Step 4) Put the vessel down on a flat, even surface and partially fill it with liquid. Add enough liquid to cover the object(s) you're going to dunk in it, but not so much that it will overflow when you dunk the object(s). It shouldn't matter what liquid you use, but water is nice. 

Step 5) Measure the distance from the rim of the vessel to the surface of the liquid and enter it in column L. We're calling that value "B" because it's the before dunking measurement. 

Step 6) Dunk whatever you need to measure the volume of in the liquid and measure the distance from the rim of the vessel to the surface of the liquid again. Enter it in column M. We're calling this value "A" because it's the after dunking measurement. If the thing you're measuring the displacement of floats you might have to push it down or weigh it down in a bag to get it all the way under. Just be careful that you account for the volume of whatever other objects you're using to sink the object of interest. Also make sure there aren't any air bubbles trapped in the thing you're sinking, unless you want the air pockets included in the volume. Note that the fluid displacement method won't work if the thing you dunk dissolves in the fluid, because dissolved matter won't displace as much fluid as solid matter.

Step 7) Once you've filled in all the yellow boxes the calculator should be giving you accurate values for volume of the fluid, volume of the fluid + object, and volume of the object. 

This is the calculator- It should work online but it will probably be less annoying if you download it. 

How my student used it: In fall 2025, one of my undergraduate research interns used an earlier version of this bucket displacement method to determine how much space is occupied by the plants in dry detention ponds with different management styles. Her results showed that even though it LOOKS like the plants in a natural meadow or wetland occupy a lot of 3d space, the volume that they actually take up is negligible. I.e., the added water storage capacity you get by mowing a dry detention pond is less than 1 vertical millimeter and doesn't justify the loss of plant habitat and ecosystem services that occurs when you mow. 

For the sake of completeness, I shall end this post with a classic meme image of a southern elephant seal (Mirounga leonina) with a bucket. 

Windsurf sail mounted to 14x23 SUP Raceboard

I tried mounting an 8.0 windsurfing sail on my 14'x23" Rivera RP SUP raceboard today. I had to do a lot of fiddling to get the universal joint attached to the carry handle on the SUP, but once I was actually on the water it was a lot of fun. I filmed some video of sailing it with my version 1.0 universal joint attachment, which was pretty wobbly, but worked. The location is the north end of Lovers Key in Bonita Springs, Florida, where there is a bridge over Big Carlos Pass, which connects the Gulf of Mexico to Estero Bay. There's some red tide beginning to affect the area again, and beachgoers including myself were coughing a bit.



After filming I redid the mast base attachment and went out for a second round of sailing. The new attachment felt a lot more secure, and emboldened me to circumnavigate Lovers Key on the craft (see GPS track). Under sail power the board felt light and sleek, and had a smooth transition from gliding to planing. It went upwind OK considering that it didn't have a daggerboard.

Starboard Race SUP Test- 12'6x24.5, 14x24.5, 14x23

The Bonita Springs paddle shop that sponsors our SUP race team, CGT Kayaks and Paddleboards, sells a couple different brands of paddleboards, including StarBoard. Not all of us on the team race the StarBoards (I ride a Riviera and some others use Hovies), but we're all curious about the pretty blue and red StarBoards and how they perform. Justin DiGiorgio had the idea to do a board test of the three different models of StarBoard AllStar that CGT currently has on the for sale / for demo rack: a 12'6x24.5 and 14'x24.5 in carbon construction, and a 14'x23 in the cheaper "hybrid" construction. The AllStars are all designed to work for both rough water and flatwater racing, with the different lengths and widths intended to suit different weights and styles of rider.

The format of the test was one we have used previously- 2x400m with a 30 second rest between them to turn around. The first 400m was downriver, and the second upriver, to cancel out any effects of current. The total paddling time of each trial was about 5 minutes. The testers were Justin (91 kg), Matt Kearney (64 kg), and me (77 kg), and we each tried each board once with long rests in between. We did the timing and distance tracking with my Speedcoach SUP 2 GPS. These are the results:



All of us were fastest on the 14x23 AllStar, slowest on the 12'6x24.5 AllStar, and intermediate in speed on the 14x24.5 AllStar. That is exactly what we would have expected because longer, narrower boards are inherently faster, at least in flatwater conditions where stability is not a limiting factor. What was interesting was how the board dimensions had more or less effect on our speed based on our body weight. As the medium weight guy, I was about equally advantaged by the 1.5" narrower board (+0.36 kph) and disadvantaged by the 1.5' shorter board (-0.33 kph). For lightweight Matt there was less of a 12'6 penalty (-0.22 kph), but unexpectedly there was also less of a narrowness advantage (+0.11 kph). Perhaps the slightly heavier weight or different flex pattern of the 14x23 "hybrid" construction board vs. the 14x24.5 carbon construction board was more of an issue for Matt. Heavyweight Justin had the greatest disadvantage on the 12'6 (-0.47 kph), but benefited from narrow width about the same amount as I did (+0.33 kph). However, for Justin we predict that the narrow width benefit would be lost quickly in rougher water due to more difficulty staying on the board.

Maximum Heart Rate and Training Zones Excel Calculator

Since getting into standup paddleboard racing I've started paying attention to physiological aspects of fitness, like Heart Rate (HR). I'm no expert in HR, but here's what I've learned from the Internets:

1. HR is a measure of how many times your heart beats in a given time period. It's usually expressed as bpm: beats per minute.
2. Your heart beats slower when you are resting, and faster when you are exercising.
3. There is a big difference between your "resting HR" and your "maximum HR".
4. Exercise scientists divide the range between resting HR and maximum HR into about 5 "zones" of exercise intensity.
6. Each person's resting HR, maximum HR, and zones are unique to that person, but there are some trends in HR based on age and fitness level.
7. Resting HR is usually 50-80 bpm, but it tends to be lower in more fit people and higher in out-of-shape people.
8. Maximum HR tends to be >200 bpm for kids, and decreases steadily with age. Fitness training doesn't increase your Max HR, but it might help maintain it as you age.
9. There's a "rule of thumb" for calculating your maximum HR. It's: Max HR = 220 - Age. There's also a more precise formula: Max HR = 211 - (0.64 x Age). (Nes et al. 2012)
10. Due to natural genetic variability, it's common for your true Max HR to be up to 20 bpm higher or lower than the Max HR predicted by the formula.
11. To figure out your true Max HR you need to do a "stress test," which involves exercising, increasing the intensity to 100%, and measuring your HR at that point. Fun!

There are lots of charts and guides figuring out your heart rate zones and training, but I wanted to make one that could be easily customized for an individual. So, I came up with the excel version below. Try it out and let me know what you think.

Wavesup with Angulo Surfa 10'4 and Exocet WindSUP 10'2

The other day I paddled in the waves with my windsurf buddy Alex. He has a cool new board- an Exocet WindSUP 10'2, which is pretty similar in dimensions and design intent to my modified Angulo Surfa 10'4. I.e., it's intended to be a maneuverable mid-sized SUP board that also functions as a full-planing windsurf board. I had never tried Alex's board before, but he let me try it that day. I liked it. It was a little more nimble and quick to accelerate than my reconfigured Angulo, but also a little less stable and less forgiving of sloppy takeoffs and such, perhaps due to the narrower nose and tail. I was relieved that my own jerry-rigged board compared pretty favorably to the latest and greatest WindSUP... at least in paddle mode. I'd still like to try Alex's board with a sail sometime.

Post race analysis of SpeedCoach SUP 2 data

Today was the second of the CGT Summer Time Trials paddle races in the Imperial River. For this one I used one of the shop's demo boards: a 14' x 27" 404 v3 raceboard in PVC construction. The board is 2.25" wider than my own board (Fanatic Falcon), making it a lot more stable and a wee bit harder to maintain at top speed. My time was 47:54, second place after Mark Athanacio who got 46:34. Both Mark and I were slower than we were in the first race, probably because we weren't drafting each other like we did that time. Also it was really hot- 31C already when the race started.

This was the first race where I used the NK SpeedCoach SUP 2 and heartrate monitor during the race. Over the last week I've been fidding with the SpeedCoach a lot and figuring out how to do some more stuff with it. There are two formats that the device can export data in: .csv and .fit. The former file type is a data table that can be opened in Microsoft Excel and used to make graphs, etc. The latter includes latitude/longitude coordinates and can draw your path in a mapping program. It's not entirely straightforward to draw your path, though. Here's how I've done it so far.

1. From the "NK Link" program that goes with the SpeedCoach, you export the data as a .fit file.
2. You upload the file to an online fit to tcx converter and download the .tcx file.
3. You use the website "GPS Visualizer" to generate a Google Earth format (.kml) file from the .tcx file. GPS Visualizer gives you lots of options for the conversion. I picked "colorize by speed" to show different rainbow colors to my track depending on how fast I was going. I'm not satisfied with that feature, though, because the colors aren't a smooth blend. My track just looks like a birthday confetti of colors and there's no easily readable key to what color is what speed.
4. You download the .kml file produced by GPS Visualizer and open it in Google Earth. Then you can get whatever zoom and angle you want to view your track.

I've combined the GPS track and some of the data from the race into the graphics below. Getting the axes to look right in the Y versus elapsed time graphs was tricky. I had to tell Excel to use 0.000694444 (which is [1/24]/60) as the major unit on the x axis so that the numbers would go minute by minute instead of in weird decimals. Also, you need to make the graphs as scatterplots, then choose "no markers" for the markers and add a connecting line. If you try to make a line graph directly it doesn't work as well. Anyway, here are the pictures and some story to go with them:

The course starts at the dock at Riverside Park in Bonita Springs, and goes East, downriver, towards the Gulf of Mexico. The river is tidally influenced so sometimes, like this morning, the water actually flows upriver. So we were paddling against the current a bit on the first leg. You can tell that going upriver was favored because of the boost of speed I get at 17 minutes, which is right after I turn around the downriver buoy and start coming upriver with the tide. The next part of the race I mostly get slower and slower, which is probably due to a combination of fatigue, my technique slipping, less favorable current, and the upriver section being narrower with more bends.

Looking at the heart rate graph you can see some neat patterns that don't show up in just the speed alone. One is that after the strain of the initial 90 seconds of sprinting, my bpm actually declines for a few minutes. That's because I'm drafting behind Brandon Gunderson's Hobie Apex 4R 14-5.75. I didn't have to paddle as often or as hard to maintain my speed then as I when I wasn't drafting. I passed Brandon after 5 minutes and he drafted me off and on until the buoy turn at 17 minutes when I lost him. Even though I was a little faster, it might have been a good strategic move to keep Brandon along and have him lead for a while so I could rest. My heart rate got really high going hard upriver in the blazing heat, sometimes getting above my age-based maximum safe heart rate recommendation of 184 bpm. At 25 minutes I could feel my heart skip a beat and thud in an uncomfortable way. That happens to me occasionally when I'm in the middle of a long hard stretch, but this is the first time I got to capture it on the heart rate monitor. I eased off the throttle to recover back down to 170ish bpm, and tried to keep below 184 until the very end of the race. It's interesting that my speed was getting slower and less consistent in the last 25% of the race even though my effort (heart rate) was steadily high. That might have something to do with my technique slipping. When fitness trainer Mark Athanacio (who had started about a minute behind me) passed me on the way to the upriver buoy he reminded me to straighten up and recover a bit between strokes to get a better breath and to be able to load more weight onto the next stroke.

I find that stroke rate is the hardest thing to interpret from the SpeedCoach data. For one thing there are always some spikes of weirdly high or low stroke rates. Low stroke rate might happen when switching sides paddling, and apparently high stroke rate might be the result of the sensor getting bumped or jostled by stepping around on the board or rocking in the waves. Despite the blips, there does seem to be a trend of high stroke rate being associated with faster speed. I think one of my instincts when I get tired is to take slower but deeper strokes. However, in terms of speed gained vs. energy spent, it might be better if I can train myself to keep a relatively fast tempo when I'm tired but reduce the power a little to not get exhausted.

Although this post has been almost all about me, I should make sure to congratulate everyone who raced today. It was a tough, hot day, and lots of people still trucked through the whole course, many of them without the benefit of fancy raceboards and weed-shedding fins like I had. I saw more than one birds' nest of pine needles and sticks shake loose from finishers' fins when they finally stopped paddling at the finish line. I'd say weed fins are essential for freshwater paddling in Florida even for non racers.

Got a new GPS gadget - SpeedCoach SUP 2

This afternoon the UPS delivery person dropped off my new geeky toy - a SpeedCoach SUP 2. It's a GPS with a high refresh rate designed to give accurate, by-the-second speedometer readings, and it has an internal accelerometer that can sense every paddle stroke you take. (It can display your strokes per minute and your distance traveled per stroke, the product of which is, of course, your speed.) Also, it uses bluetooth wireless communication to talk to a heart rate sensor that you wear around your chest. The bluetooth lets you extract the data from the unit to your PC for analysis, which I think is super cool. You can also use the wireless to download timed interval "workouts" to the SpeedCoach, which will then tell you when to go fast, when to rest, etc. There are five workout programs already in the machine when it comes out of the box, and you can tweak them and save them if you want to.

I had to rush to get on the water to try the toy today because the radar showed a thunderstorm coming in from the east. I did a 1.61 km (1 mile) paddle downstream in the Imperial River, then took a rest and did the same thing coming back upstream. Going downstream I didn't start the SpeedCoach data recording properly, so I didn't get any data for that section. Going upstream and upwind after I was already a little tired I didn't get the most impressive times, but the data was still useful. Here's what it looked like when I graphed it in Microsoft Excel:

Speed- It took me 20 seconds or so to get up to speed. Quicker acceleration is something I need to work on, since this could really hurt me in a race with lots of buoy turns where you have to stop and then accelerate again. I also notice that there are lots of little ups and downs in the speed, which might have to do with wind, current, and water depths changes as I was going up the bends of the river. I definitely noticed just by looking at the screen on the SpeedCoach that I was a lot slower in shallow water, and a lot faster when I could find an eddy in the downstream current. I'm sure there's a "human element" to the ups and downs, too, with my wavering will and focus. Strokes per minute- I take about 56 strokes per minute on average, but when I take more strokes per minute I'm faster. There are times that my stroke rate seems to suddenly dip really low, which may be when I'm switching paddling sides or may be when the accelerometer fails to pick up strokes. Heart rate- My resting heart rate (not shown) is 65-70 bpm. My "warmed up" heart rate (after paddling hard for a mile then taking a couple minutes to rest) is about 120. It took about a minute of paddling hard for my heart to go from 120 to 170ish, then it gradually got up to 180ish after about 10 minutes. I think around 180 is my hard-workout max.

Hopefully the data this gizmo delivers will give me some better insight into what works and what doesn't work for going faster. :)

Pics of Windsurfing the 14' Fanatic Race SUP

The other day my wife Rhonda graciously came to the beach with me after work to take some pictures of me windsurfing the 14' Fanatic Falcon SUP that I recently converted into a windsurf. I would have gotten some onboard video, too, but I loaned my GoPro to my graduate student a couple months ago and haven't gotten it back yet. Anyway, the pics are below. It was a day with disorganized knee-high waves and 5-10 knot side-offshore winds, fading to 0-5 knots. I used a 6.4 sail.

When the wind got to too light to get around with the sail I paddled for a bit. Man, trying to surf a race sup is hard. It's really tippy, it takes a long time to turn around, and when you do catch a wave it's hard not to crash. But it's fun.

Using 14' Fanatic Falcon Race SUP for Windsurfing

As my wife Rhonda says, I am a notorious "min-maxer" when it comes to choosing and fine-tuning my watersports equipment. I proved this recently by swapping my nearly-new racing paddleboard (a beautiful blue 14' x 26" 404 Carbon Pintail Zeedonk) for a different model (a beautiful red 14' x 27.25" Fanatic Falcon).

The Fanatic was on consignment at CGT Kayaks and Paddleboards and I put my Zeedonk on consignment in its place. If you're in the market for a super-lightweight, all-carbon race sup for under $900 you can find my Zeedonk at CGT. Say you saw it on my blog and they might give you a discount. Here is why I did the switch:

1. I wanted to put a mast-track in the race SUP to mount a windsurfing sail, but I wasn't sure the 10 kg Zeedonk would hold up to the extra abuse it would take in windsurfing mode. The Fanatic is a few kg heavier with a thicker skin more like a standard windsurf, so I figured it would be a safer bet for windsuring use.
2. The noses on the two boards are different. The piercing bow of the Zeedonk works really well for paddling in flat water, but I could imagine it being tricky to negotiate through chop at higher windsurfing speeds. In contrast, the bow on the Fanatic is blunt and upturned, which I figured would make it more "self-trimming" in rough water. (Both boards are supposed to be good for open-ocean "downwinder" paddling and "catching bumps," but I think the Zeedonk takes a more active approach to fore-aft trim when doing that.)
3. When I borrowed the Fanatic for a test-paddle in the Imperial River I found that it was only a little slower than the Zeedonk. That was important, because I didn't want to totally sacrifice my hopes of keeping up with the faster SUP racers in the CGT race series this year.

So far I've been quite happy with the Fanatic Falcon. After pushing myself through some more training runs on the Imperial River, trying a new fin, and adjusting to the board's different style, I've got my course times down to where they were on the Zeedonk. The board is definitely an unusual shape, but it works. The bulbous nose is its most notable feature.

The nose is supposed to help it bob over waves and chop that it hits at a straight-on or side-on angle, and help prevent it from "pearling" under the water when riding down a wave. I paddled the board one time in choppy waves on the Gulf of Mexico. Though it was a lot less stable and less maneuverable than my Exocet WindSUP and Angulo Surfa, it was pretty powerful for catching waves and getting long, fast rides.

Balancing out the bulbous nose is a long-tapered, narrow tail with the fin set unusually far forward. This makes the overall outline of the board a teardrop shape, like the cross-section of a fin. There's minimal wake behind the board when in motion which implies minimal turbulent drag.

The weird straps on the front of the board are like suitcase handles for when you're running the board into or out of the water at the start or finish of a paddle race from the beach. I'm not sure I'll ever use them when racing, but they came in handy as tie-down points when I improvised a windsurf sail attachment system for testing purposes. (I wanted to see roughly if the board was sailable before I put any permanent holes in it.)

For the improvised system I taped a foam block to the bottom of a universal joint so that it could rest on the deck of the board without denting it. Then I tied the universal joint in place with a line to each of the straps, and a line to a little block of wood that I wedged into the recessed carry handle of the board. The carry handle is about in the middle of the board, and I assumed that the mast base would need to be just a bit in front of that.

When I got the board to the beach to test it with the jury-rigged sail attachment it was windier than I had expected; about 10-15 mph with some chop on the Gulf of Mexico. I rigged a 6.4 sail and took off like a shot. The board definitely accelerates quickly and goes fast in a semi-planing mode. In gusts it would get into fully-planing mode, but with a rooster tail of spray behind the tail, indicating a less than optimal pattern of water release from the unusual tail. The board handled the chop very well and went upwind at a steep angle when railed to windward. It took some work to tack, as expected, but it did tack. Jibing was easy because it would keep gliding on the long, voluminous tail even when I stepped far back on the board to make it pivot around. Overall it exceeded my expectations as a windsurf board, so decided to go ahead with the mast track installation.

The first step was to peel away the deck pad where the mast track would go.

The next step was to route out a hole a little bigger than the mast track. I filled the hole with a sandwich of high density pink insulation foam, with a layer of fiberglass between the two thin slabs of pink foam and a layer of fiberglass and filler between the pink foam and the foam of the board's interior.

After that cured I routed a hole within the pink foam just big enough for the mast track itself. (I bought the mast track from Roy Massey at Ace Performer.) The next day I put the mast track itself in, in a manner similar to that used for the pink foam. The final phase was to fair the excess fiberglass and epoxy off the top of the mast track and lay three layers of fiberglass over the area, overlapping with the mast track, pink foam, and some of the original decking of the board. I topped it all off with the piece of deck padding that I'd saved so it will look good less conspicuous.

I'm now on vacation at my folks house in North Carolina, but I'm looking forward to testing the real mast track when I get home in the new year. I'm curious how the board will work in really light conditions with an 8.0 or 9.5 sail, as sort of a poor-man's Starboard Serenity / K15.

In other news, my dog gave me a scare the other day when she fell off the back of my WindSUP and took a moment to pop back up to the surface, swimming poorly. To be safe we're going to have her wear this lifejacket from now on. I think she looks good in it.

Cool Way to Measure Surface Area of a SUP Paddle Blade

I've been enjoying flat-water standup paddleboarding a lot since doing some informal races this fall and buying a 14' race SUP a few weeks ago. A big part of the enjoyment is striving to go faster. The three main ways to do that seem to be, 1) paddling harder, 2) getting more fit, 3) using better equipment, and 4) developing better technique. I've noticed definite improvements that I can attribute to 1, 2, and 3. Changes in technique have probably had some effect, too, but it has been hard for me to distinguish those effects from the others.

Anyway, as I was geeking out reading about SUP gear and techniques online, I came across some guidelines for what size paddle blade you should use. It makes sense that there would be an optimal size for paddle blades, since a very small blade wouldn't catch enough water to push you forward effectively, while a very large blade would make your strokes awkward, slow, and tiring. Body weight seems to be the main determinant of optimal blade size. Since I weigh around 175 pounds / 80 kg I ought to use a paddle blade with an area between 90 and 100 inches squared.

Its a little more complicated than that, though. Apparently there are at least two other things that affect optimal paddle size: your strength to weight ratio and the length of the race you'll be paddling in. If you're super strong for your weight, like a wrestler or a gymnast, then you can benefit from maybe a 10% or so bigger paddle blade than someone your weight would normally use. If you're doing a short "sprint" race then you might also benefit from a bigger blade. On the other hand, a smaller than normal blade could help in a long-distance race by preventing muscle fatigue. I think I can ignore the race length factor, since the race I do is medium length. Regarding strength to weight ratio, I have no idea how that might be calculated, but I can do about 15 pullups so I'll go out on a limb and say I'm above average in that department. So 100 inches squared would probably be better than 90 inches squared for me.

The only thing is, I bought my paddles a long time ago and I had no idea how big the blades were and whether they were the right size for me or not. Since they're odd shapes with rounded edges it would be hard to figure out their area by normal math and measurement. Fortunately, I'm a scientist, and I realized that I could use the same image analysis software that I use to quantify seagrass blade areas to quantify my paddle blade areas. The software is "ImageJ," a free program that you can download from the US National Institute of Health. I think it was originally developed to help medical doctors measure the size of suspicious moles, etc. It takes a little fiddling to figure out all the features of ImageJ, but the basic method I used to measure my paddle blade areas is this:

1. Put the paddles on a flat surface with an even color that contrasts sharply with the color of the paddles.
2. Lay a ruler or other object of known size next to the paddles.
3. Hold a camera steady and level above the paddles and take a picture.
4. Shrink the file size a bit so ImageJ can manage the picture.
5. Open the picture in ImageJ.
6. Use the line tool to trace 0 - 12 inches on the ruler, and use "Analyze, Set Scale" to set that scale at 12 inches.
7. Use the "Adjust, Color Threshold" menu to turn the image to black and white, and twiddle the levels so that the paddles show up as a simple block color on a blank background.
8. Use the paintbrush tool to cut off the heads of the paddles where they meet the shaft, and fix any gaps or spillovers in the paddle shapes.
9. Use the magic wand tool to select a paddle head, and then use "Analyze, Measure" to get its area, which will be in inches squared.

Original image-

Processing image in ImageJ-

I found that my Angulo carbon fiber paddle head is 97.2 inches squared, and that my cheap aluminum and plastic paddle head is 106.8 inches squared. It will be hard to make a fair comparison of the two paddles since the aluminum one is about twice as heavy, but I'll give the big one a try on the race course to see if it seems like the extra size is in any way helpful.

New SUP: 404 14' Pintail Zeedonk

CGT Kayaks and Paddleboards is the outfitter / shop that organized the Imperial River summer race series that I did the last part of this fall. CGT recently opened a new brick-and-mortar shop in downtown Bonita Springs, just a few blocks from my house. When I heard that they had a line on some barely-used demo boards I called dibs on a 14' carbon fiber race sup. I'd had the bug to get a race-specific SUP since doing the summer races, but was waiting for the right deal to come along. This one was just $800, which is real cheap for that sort of thing.

The sup is a "Pintail Zeedonk" from the brand "404 Paddleboards." It's 427 x 67 cm, with a very pointy nose, a long flat section, and some slight vee and rocker in the pintail section. "Zeedonk" is supposed to mean it's fast as a zebra but stable as a donkey. I'm not familiar with donkey stability, but I did notice that it was a lot more stable than the only other race sup I've ever tried- a 61 cm wide Starboard.

Of course the Zeedonk was less stable than my 360 x 80 cm wide Exocet WindSUP (right side of picture), but it's also significantly faster.

I took the Zeedonk for a practice run on the 4.5 mile Imperial River SUP course yesterday and finished in 0:51:27, which is about 6 minutes quicker than my best ever time on the WindSUP. Having to change out of my wetsuit top during the course, and getting some pine needles stuck on the non-weed fin I was using might have slowed me down, so I'm thinking that with some more tuning and training I could break the 50 minute barrier. That's going to be my goal for the time being.

One of the things that I gather is important for getting the max speed from these race sups is standing in the right spot; not too far forward to or too far back. In the picture above it looks like the middle of the board is low and the nose and tail are high, but when it's in motion its own wake wraps around it in such a way that the bow entry and tail release seem pretty good.

As one might imagine, I'm already contemplating putting a mast track on the board to see how it works as a windsurf. I think the rocker is flat enough that it could plane, or at least glide really fast. My only hesitation is that the construction is quite light and I'm not sure the board would stand up to bouncing through chop at windsurf planing speed. I'll enjoy it as just a SUP for a while before I decide if I'm going to do a conversion or not.

Gonna try a SUP race in Bonita Springs

I'm going to test my mettle next Saturday at a local paddleboard race. The race is part of a series hosted by "Calusa Ghost Tours," a local kayak/sup outfitter. The proceeds from the race fee will fund the Bonita Springs Historical Society, which is doing some things that I really like, such as helping raise money to preserve the old-timey Everglades Wonder Gardens zoo/park/art-gallery in my neighborhood.

The race is a 4.5 mile round trip down and back up a section of the black-water Imperial River. It's the same area I usually paddle when the wind and surf are down and I just need to get on the water.

I'll use the Exocet WindSUP 11'8" with a small weed-fin. Even though the WindSUP is heavy, it has good glide and I think it will paddle faster on flat water than my Angulo 10'4". I tried the course last night and finished in 1:08 paddling pretty close to as hard as I could. I would need to be finishing about 20 minutes faster to win the race, based on the previous winners times, but I think I'll at least be able to stay somewhere in the pack. I'm going to make it a personal goal (maybe a long term goal) to bring my time down to 1:00 even. To help me towards that end I'll need to practice my padding technique and improve my cardiovascular fitness and core strength. I'm also trying a technological fix, by shortening my paddle by about 20 cm. (Since I got the paddle it has definitely been too long, but I never bothered to adjust it because I wasn't trying to maximize my paddling speed or anything.) We'll see how it all works out.

Rundown of Spring 2014

I had a busy spring semester of teaching and research at Florida Gulf Coast University and didn't have much leisure time to spend on blogging. So now that I've turned in all my final grades and shifted gears to research-only mode for summertime, I'll catch up on some of the things I would have blogged about if I hadn't been so busy.

I kept my first-year students busy with lab activities in my "Marine Systems" class.

I hired a research technician to help me with labwork and fieldwork in the Caloosahatchee Estuary. She and my graduate student also made an official school webpage for me: http://blogs.fgcu.edu/douglasslab/

Sometimes the fieldwork was awesome.

In the lower part of the Caloosahatchee Estuary we saw cool saltwater critters like this Spotted Batfish.

Sometimes the fieldwork was not awesome, but we still got it done.

In the upper Caloosahatchee Estuary, where the water is mostly fresh, we searched for signs of Vallisneria americana, a grasslike underwater plant. As recently as the 1990s, Vallisneria formed lush underwater meadows in this area, full of brackish-water loving fishes and crustaceans. Unfortunately, unstable salinities resulting from irregular water flows through a man-made structure on the Caloosahatchee (the S-79 lock and dam) have decimated the Vallisneria. Where we searched near a bird rookery island in March, all we found were a few solitary blades of the grass, plus lots of gross mud and cracked eggshells and such.

The one thing I did make time to blog about this spring was windsurfing, although there were a few good windsurfing sessions and projects that I neglected to document. One project was changing the "double concave" bottom on my formula board to a "flat vee." It helped the board plane earlier and easier, and hasn't had any negative impacts that I can tell.

Intermediate stage in the bottom-shape conversion, where I had routed out the concave sections before filling them flush with foam slabs.

Another windsurfing project was shipping the RRD beginner board I'd picked up on craiglist to a buyer in the Northeast. Shipping windsurfing gear is an expensive boondoggle.

I used about four rolls of packing tape and 20 cardboard boxes to wrap this on up, hence the sarcophagus appearance.

My dog Grace learned how to SUP. I lured her onto the board with treats, but it was hardly necessary because she took to it quite naturally.

She's so calm on the water that she'll even lie down and rest on the board.

The Exocet WindSUP 11'8", with it's ample width and flotation, is nearly perfect for dog SUPing, though if I was only using it for that I would put some grippy padding on the nose because Grace likes to stand right on the bow.

There were some interesting botanical events around my house in Bonita Springs.

One was the sexual maturation of a large agave plant in our front yard. It shot up a towering inflorescence, which began looking like a giant asparagus, then morphed into a multi-tiered flower structure as tall as our royal palm tree.

Another botanical event was our replacement of a ratty looking Crape Myrtle with some cute little Bougainvilleas.

Rhonda also bought us a "tasteful" garden gnome sculpture. I assume our next purchase will be a pink plastic flamingo.

I shouldn't forget to mention Rhonda's HUGE spring news: She achieved her life's goal of getting a big book publishing contract. Titan Books bought her latest sci-fi novel, plus two more (not written yet) from the same trilogy.

Despite being a famous author, Rhonda still works full time for NASDAQ and works as a full-time dog parent and semi-pro miniature golfer.

Besides the worrying environmental trends I've seen during my research outings in the Caloosahatchee Estuary, there have been some other interesting and upsetting things going on with the environment of Southwest Florida. One of them is the relentless conversion of undeveloped greenspace to housing developments and shopping centers.

This is a political cartoon from outside one of my colleagues' offices. It was drawn in 1997. The areas around FGCU now look a lot more like the 2020 picture!

In addition to the permanent loss of terrestrial wildlife habitat when these developments are built, I'm concerned about the additional runoff pollution that they'll introduce to the area's already strained waterways.

The canal near our house, for example, is looking really gunky.

One thing that I think degrades the health of the canal is that it's always being sprayed with herbicide. Some of the spraying is because its next to some disused railroad tracks. Though they don't maintain the tracks themselves in a state that would allow a train to pass, they still think it's necessary to poison every living thing in the right-of-way until its a shriveled brown wisp. Not all the herbicide is for the railroad tracks, though. They actually spray it right in/on the water of the canal and the wetland plants around it. I guess the government (city, county, state?) worries that it will get too clogged with plants to effectively drain water off the land in a flood. Some of the plants are non-native, too, like the beautiful floating "Water Hyacinth." The Lee County Hyacinth Control District often poisons them, but sometimes uses other methods, like introducing herbivorous fishes.

Canal filling up with live hyacinths before poisoning.

Canal full of live and dead hyacinths, and poison, after poisoning.

I'm not an expert, but my instinct as a scientist is that the best thing to do if the floating plants become a nuisance would be to sweep them up off the surface of the water with some kind of giant net or rake, then turn them into nutrient-rich compost for agriculture and gardening. You see, when aquatic plants grow they absorb the excess nutrient pollution from the water. If you kill them and leave them in the water to rot, all the nutrients and pollution (plus the herbicide) go right back into the water, causing problems downstream and in the ocean. But if you scooped them out instead you'd be removing the excess nutrient pollution- a win-win scenario.

Another uncool environmental trend is the fad of shark-fishing off the beach. Lots of macho young dudes will show up at the beach around sunset and set up tons of rods right in the area where everyone is swimming, beachcombing, and windsurfing. Sometimes they'll cast their baits out, and other times they'll use a kayak to put bigger baits out really far to try to catch bigger sharks.

Believe it or not, this small, butchered shark was actually being used as BAIT by a young man fishing off Bonita Beach Access #10. After an unsuccessful night of fishing he tossed it away in the water, where it drifted back and forth in the waves until bumping into an unsuspecting swimmer the next day, right before this picture was taken. Though there appear to be decent populations of small and medium sized sharks in Florida, their populations are actually extremely low compared to their healthy, historical abundance, and many shark species are still in decline. So I don't think catch and kill shark fishing should be allowed.

On a completely different note, I'm going to need a new windsurfing vehicle soon. The speedometer and odometer have never worked, the gas gauge doesn't work, the air conditioner doesn't work, and now the backhatch is rusting off. I might have to make a last-minute new-used minivan purchase before my honeymoon trip to the Florida Keys this June.

I'll stop there for now.