SpeedCoach Additional Information

1. How Moving Water Affects Your SpeedCoach
2. FAQ's About Calibration
3. Racing Tricks with your SpeedCoach
4. Seat Racing with your SpeedCoach

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How Moving Water Affects Your SpeedCoach

A common misconception of the SpeedCoach system is that the measurements will be affected by moving water. Actually, the SpeedCoach meter was designed so that it is completely unaffected by currents and tides. Understanding this can help you train more effectively.

Let's start with a basic analogy for rowing on moving water. Imagine using the moving walkway between terminals at an airport. Before getting on the walkway, assume you are walking at a speed of 3 mph. When you hop on the walkway, you continue to walk at 3 mph, but the walkway adds another 2 mph. To the observer standing at a gate, it looks like you are traveling at 5 mph. If you were training for the Airport Terminal Olympics, you would want to know your walking speed of 3 mph, not the observed 5 mph.

Now imagine that you've arrived at your gate, only to find that the gate for your flight has been changed. You get back on the same moving walkway, but this time walking in the opposite direction. You continue to walk at 3 mph on the walkway, which is moving at 2 mph in the other direction. But to the observer standing the gate, you are moving 1 mph. (In fact, he thinks about calling security.)

The speed that is most important to your rowing is the same as the 3 mph walking speed. Likewise, you want to know how fast your boat is moving through the water, NOT how fast your boat is moving compared to land. It doesn't matter if your boat is traveling upstream or downstream, your speed through the water will be the same (assuming the pressure is the same).

Let's use an example of two 1000 meter pieces on a racecourse, one upstream and one downstream. You finish the downstream piece in 3:30, drink some water, and get a couple minutes of rest. Now you turn around do the upriver piece in 3:52. We all know that you can't compare the times for these pieces, because one was downstream and one was upstream. The SpeedCoach meter, however, would have displayed the same speed in either direction.

There is a huge benefit to using a speedometer when training. If you use the distance measured by the SpeedCoach meter, as opposed to the land marked distance, you can compare pieces in either direction. Furthermore, you can compare pieces from day to day, even if the current or tide has changed! Please note that the wind WILL affect the measured speed. This is a much different phenomenon than moving water, because the wind is actually pushing against the boat. Sorry. But we are working on that. (No, not really.)

One more way to think about this is to imagine rowing upstream at exactly the same speed as the current. Your boat will appear to be standing still to the person on shore, even though you're working pretty hard to keep your boat from moving backwards. Fortunately, the SpeedCoach meter will continue to show your boat speed and count off the meters rowed through the water. (By the way, a GPS would indicate no speed and no distance. It has no idea if you are on land, water, or a moving walkway at the airport.)

FAQ's About Calibration

There are many misconceptions surrounding calibration when it comes to using a SpeedCoach. Here is some background information that will hopefully help you set up your SpeedCoach for your individual needs.

All SpeedCoaches (Red, Gold and XL) have a "calibration" value that helps the unit compensate for different impeller locations and to perform accurately on that particular boat. All boats are shaped differently and hull integrity can be jeopardized due to damage. Additionally, due to sealed bulkheads and the boat's internal structure, sometimes it is impossible to mount the impeller & blue speed sensor exactly 5 meters from the bow. To compensate for these inconsistencies from boat to boat, you can adjust your SpeedCoach's calibration value to reflect your particular boat.

This individual calibration is NOT necessary for the SpeedCoach to be a useful training tool. When the impeller is mounted 5 meters (16' 3") from the bow, the factory calibration value of 1.000 will provide readings that are very close to accurate. And even if your unit is not calibrated, you will always see relative changes in boat speed.

For example, if Monday your average split was 1:57 and Tuesday your average split is 1:55, then you are going faster on Tuesday than you were on Monday. Additionally, if you are using the SpeedCoach to seat race athletes, and the average speed for the lineup with Joe is 1:45, and the average speed for the lineup with Sam is 1:42, then Sam's lineup is moving the boat faster.

So why calibrate? Many teams use the SpeedCoach to monitor their speed based on a time standard that they are trying to achieve. The SpeedCoach reading absolutely accurately is important in this instance, and calibration would be an extra step to ensure this.

For example, if your crew is preparing for their championship race and you know that typically, crews that advance to the final go around/under 8:00, then you can build a powerful training plan based on knowing that you need to average a 2:00 per 500 meter split. You can build in target splits for pretty much every workout all season, and by gauging your daily progress compared to the targets, you'll be able to anticipate how your crew will stack up on race day.

Whether to calibrate your unit or just go with the factory calibration of 1.000 is an individual decision based on your training needs. If you decide that you want to calibrate your SpeedCoach, the formula is at the end of this post. (The SpeedCoach XL's feature a nifty calibration routine that steps you through the process and does the math for you.)

A few parting notes: * Calibration is boat and impeller location specific. If the unit is moved to a new boat, or the location of the impeller is modified, it is recommended that the unit be recalibrated.

* If you are in a team setting with mulitple boats and SpeedCoaches, if you are going to calibrate, try to keep the same unit with the same boat. This way, you won't need to change the calibration value on the SpeedCoach unit every day. Additionally, once you calibrate a unit to a particular boat, consider marking the impeller location with permanent marker and jotting down the calibration value somewhere on the boat so it's easy to remember.

* It is recommended that regardless of whether you plan to calibrate or not, the impeller should be placed as close to 5 meters from the bow as possible. Every boat has a turbulent boundary layer of water underneath the shell, and as you move to the stern, the layer gets larger. Placing the impeller closer to the stern increases the chance that the water will be too turbulent for the impeller to spin consistently. NK has wiring harnesses for every size boat so that the blue speed sensor can be mounted 5 meters from the bow.

* 5 meters from the bow may seem like a random number, but on most singles, that's typically an accessible area. In most sweep boats, that's typically right around 2 seat, also an easily accessible area.

Calibration Routine To calibrate the SpeedCoach, row over a measured distance on still water (on flowing water, row both up and down stream and average the results shown on the display). Then, use the following formula to obtain the new calibration value:

(Old Cal Value) (True Distance)/Displayed Distance= New Cal Value

For example, if the known rowed distance is 1 mile, but the display shows 0.92, the calibration value would be: (1.00) (1.00)/0.92 = 1.086

Racing Tricks with your SpeedCoach

Here are some tips for getting the most out of your boat using your SpeedCoach System.

Having trouble finding the right cadence? Finding the most effective start and sprint is often a difficult process. Simply rowing at the highest rate possible does not guarantee the fastest boat speed. Knowing your boat speed can help you find your most effective rates during these critical parts of the race.

For example, try the following 40-stroke sprint workout: Build to base rating and hold for ten strokes. Increase the rate by 2 beats every ten strokes while taking note of the splits on the SpeedCoach monitor. Make sure that the splits go down for every shift up in rate. The point at which the splits stop going down is probably your highest effective stroke rate.

This same type of workout can be applied to the start and settle strokes, too. Sometimes the most efficient base cadence is really a beat or two lower than you think!

Do you row on a river or tidal area? A SpeedCoach can make sure you are training for the right distance. Tides and current can change your practice conditions on a daily basis. Even within different lanes on a race course, the water speed can differ greatly. One day it could take you 6:30 to do 2k, and the next day it could take 7:00. If you use a SpeedCoach, the distance is not influenced by the moving water. It ONLY measures the distance that your boat has traveled through the water. This is why the distance on a SpeedCoach doesn't always match up with the land distance on a marked course.

Knowing that you are training for the same distance every day with a SpeedCoach can add a element of consistency that is difficult to achieve with many river and tidal bodies of water.

Racing on any new, unfamiliar or unmarked race courses? Knowing exactly where you are during the race is often a guessing game. Not with your SpeedCoach meter. Set up your unit so that it reads your pace (/500) and distance (m). Put the unit in STOP mode. When set at the starting line, take the unit out of STOP mode. While most people use landmarks for the 500, 1000, & 1500 meter lines, you will have an exact measurement showing you these points (provided your course is well measured and your SpeedCoach is calibrated). You will know right where to make your moves and how far you have to go.

What about impeller drag? The question of drag often times comes up when looking at the pros and cons of racing with a SpeedCoach. When the SpeedCoach impeller was being developed, laboratory tests were performed in a tow tank to determine drag effects. They found that for a single shell, the impeller drag was less than 1% of the total drag of the boat, and proportionately smaller for larger boats. Simply put, over a 2000m race, it adds less than 0.5 second.

While plenty of races are won and lost by smaller margins than that, consider the additional information that a SpeedCoach can provide during a race. Ultimately, each racer needs to decide for themselves if the pros outweigh the cons. One way to look at it is to imagine doing a 2k-erg piece with no monitor - racing with a SpeedCoach gives you the same information that the monitor gives you on the erg.

Seat Racing with your SpeedCoach

Now that it's early spring, erg rooms grow quieter and more boats head out on the water. Everyone's pulled their test pieces and rowers have established themselves at the head of the pack. But wait, ergs don't float! Right? How do you know your top dog on the erg isn't dead weight in the boat? And what about the one who rows with the best of them, but struggles on the erg? Who's going to make the boat? There are many philosophies on how to seat race, and what ever works for you is great. Here's another option.

Most people believe the SpeedCoach system is designed for smaller boats, like singles and doubles. But in fact, it can also be very effective in larger team boats. Let's say you have an eight to fill. You start with your top eight erg scores. Here's a ninth that is a very steady rower and shows some real improvement. They deserve a shot at the boat. Instead of breaking into fours to seat race, send your normal eight out with a SpeedCoach system and switch one rower during practice. For example, run a series of minute pieces, building the rate up each minute to race pace. Note the average boat speed for each piece. Now switch rowers. Repeat this series and again note the boat speed. Immediately, you will have numerical feedback as to their effectiveness in the boat. Simply put: if the split ain't lower - the boat ain't goin' faster.

You can even perform long-term seat racing by comparing lineups over several days. Just have your coxswains record the average speed during either steady state or pieces. Then run a similar workout with a different lineup to see if the boat speed increases or decreases. This allows the rowers enough time to get comfortable in their lineup, as opposed to switching boats every 1000 meters. It also won't take long before your coxswains start to get a feeling for typical boat speed for a given workout.

This type of racing is ideal for smaller programs with barely enough rowers to fill an eight. These programs don't have the luxury of racing a fleet of fours to find boat movers. Instead, just switch one rower at a time and check the boat speed. Mixing the lineup with the same eight rowers may also uncover a faster lineup. However, without knowing their boat speed, it's difficult to quickly find the best lineup.

Keep in mind that changes in current will NOT affect the measured speed, but wind and fatigue should be taken into account. In a future article, we'll discuss why water current will not affect your speed measurements.