WD12 - 3.5 and 6.4 mph. Speeds are no wind, slack tide and measured with GPS. In addition, a photo at the higher speed shows a wave pattern indicating that the boat was at hull speed.

I'll also add a run pace, a speed that's work but which can be kept up for an hour or two - 4.2 mph.

Laszlo

Passagemaker Dinghy - 3 - 3.5 mph all day long, 4.5 mph flat out, which is about hull speed for this Rubenesque lady, though she'll do more under sail sometimes.

.....Michael

For the Northeaster Dory as a Tandem (my wife with 6' oars and I with 8'):

Easy pace -- 3.5 mph

Sprint pace -- 5.5 mph   

Northeaster Dory
No GPS, over a measured 3.25km track, fixed seat, 8.5' oars, bare boat. Pace was what Laszlo calls a run pace. It was my first time rowing that distance, could improve time with continued workouts. Actual distance over ground would have been slightly longer with all the wandering. Breeze was 90 degrees to direction so no help there.

Out: foul tide, 1.25 hours
Back: mostly slack water, 1 hour 

Was rowing in company with David in an Annapolis Wherry, sliding seat, 9' carbon fiber hatchets. He absolutely crushed me. Easily arrived at either end 15 minutes before me and at a loping pace.

   Shearwater Sport Sectional --

Easy paddling at 3.9 mph (3.7 - 4.2)

Sprint pace at 6.0 for 30 seconds

There was a slight breeze, sometimes with me, sometimes against me, and sometimes calm. The breeze seems to make little difference in this boat.

Silver Salt, I'm not sure I understand your data. An hour to cover 3.25 km? That's slightly over 2 miles. I would think you could get well over 4 miles an hour at run pace in the dory. What am I misunderstanding?   

   Nautical Mile, not Knotical Mile. ;-p

I decided to flesh out this discussion by mining some data from past threads on the Forum. For consistency I converted speed in nautical miles to standard mph. There is more data to be mined in the Forum archives, and I will try to add it as I find the time.

Pax 20 -- easy pace -- 6.0 mph; race pace -- 6.8 mph https://www.clcboats.com/forum/clcforum/thread/41761.html

Shearwater Double -- easy pace 4.0 - 4.5 mph -- 6+ mph at exercise effort https://www.clcboats.com/forum/clcforum/thread/39492.html
https://www.clcboats.com/forum/clcforum/thread/31343.html

Waterlust Canoe Hobie drive -- easy pace 3.5 mph https://www.clcboats.com/forum/clcforum/thread/39295.html

Skerry -- average rowing -- 4 mph  https://www.clcboats.com/forum/clcforum/thread/32497.html

Annapolis Wherry Tandem (rowed solo) -- 7 mph sustained for an hour https://www.clcboats.com/forum/clcforum/thread/25369.html

Chesapeake 17LT -- 4.7 mph sustained for 2-3 hours https://www.clcboats.com/forum/clcforum/thread/25369.html

 I have re-posted the Google Earth graph from the Skerry link in Birch2's post above as the image host has been changed (scroll down the page). For what it's worth, I'm 3 years older but can still achieve the same pace if the wind isn't too bad.  

I must express a little skepticism that you can cruise at 7 knots for an hour  in a tandem wherry rowing solo. I'm by no means a serious rower, but with my son I have (briefly) rowed the TAW to over 6 mph and at that speed it puts up an impressive wake. For a single rower to throw up a much higher wake for an entire hour would be quite a performance.

Vaclav Stejskal at One Ocean Kayaks has some nice figures for drag vs speed in a variety of 5-6 meter hulls ( http://www.oneoceankayaks.com/kayakpro/kayakgrid.htm#waveanch )

that show how speeding up from 6 to 7 knots entails an 80%  increase in drag force. That's because 6 knots is about the 'hull speed' for craft of this length. 

For comparison, the Olympic single scull record for 2 km (6:30.74 ) is 18.3 km/hr or 9.9 knots. Because racing shells are over 25 feet long, they should be expected to have a higher hull speed the TAW, whose wetted length is around 18 feet. 

Has anybody rowed a Tandem Annapolis Wherry over six nautical miles in an hour?

   Due to advancing age, I seem mixed things up. In the first sentence please read 7 mph, not 7 knots. The rest of my comment is as I meant it.

NE Dory. I make about 3 knots at a very relaxed pace. I always have the rigging up so that means I'm rowing with the boom flapping about my ears. Also because of the mast, sitting on the middle thwart with my crew on the aft thwart. This may not make for the best trim, apart from when camping gear is piled in the bow. No sprint data, I'm afraid.

Addendum: standard 8ft Spruce oars ordered through CLC.

   I took my 57-year-old 10' Folbot Junior out for a spin this morning, in part to see how it compares with the 14' 6" Shearwater Sport.

Easy cruising speed is 3.6 mph (as opposed to 3.9 mph) and sprint speed is 5 mph (as opposed to 6 mph).

By the way, the link is to a brief YouTube tribute I made to the boat.

   We went once on a club paddle where John, a farmer from Ocala, paddled a 10ft plastic tube at the speed our 17ft sea kayaks were cruising at. But most times that just ain't going to happen.  Howeverr the point is that its not the boat speed here but the skills of the paddler and strength of the paddler that determine ultimate speed. 

I'm a little interested in y'alls method for determining "cruise speed" and "sprint" . Are you dead reckoning or using the average moving rate reading from your GPS? 

My remarks 9/7 regarding a Passagemaker Dinghy were referring to readings from a Garmin Etrex 10 hiking GPS, converted from knots to MPH.

.....Michael

  I use the free Strava app on my phone. It gives me a GPS track and its "Anaylsis" function allows me to highlight parts of that track so that I can see time, distance, and average speed. Here, for example, is a link to an image of my 5-mile paddle last month in my Shearwater Sport Sectional:

Complete GPS track

You can see that my speed varied, but I averaged 4.3 mph.

Since I've been interested in "cruising speed," I highlighted a smaller section where the speed seemed fairly consistent (when I crossed the lake in my first mile);

Cruising speed

My average was 4.3 mph for that mile.

Sprint speed is something I can maintain for only 30 seconds or so.

Sprint speed

This sprint averaged 6.1 mph.

Your point that "cruising speed" depends at least as much on the engine as on the boat is a good one. My wife paddled almost identical boats a couple of days ago. My easy cruising speed in the 10' Folbot was 3.6 mph. Hers in an almsot identical boat was 2.8 mph.

Everybody is different . . . which makes boat speed comparisons difficult.

   Shearwater 17 averaging 5mph cruising speed in fair conditions 

This topic has been up for a few weeks now, and it has taken me a while to answer because I wanted to put together a thoughtful reply. 

I’ll start out with the caveat that my post below applies to kayaks.  I do row my Goat Island Skiff a bit, but not enough that I can provide any meaningful data.

It probably goes without saying, but the best way to compare boats is to paddle them, ideally side by side in the conditions that they will be used.  Paddler power is half of the speed equation, and power is significantly impacted by a number of factors (comfort, stability, stroke dynamics, etc) which can only be determined when you put your butt in a boat and paddle it for a while.  This is a lesson that I recently learned the hard way when I bought a commercial race boat without paddling it.  Although it is by far the fastest hull that I own, it becomes a medieval torture device after about 30 minutes and speed drops precipitously.

In the homebuilt world, it is sometimes very difficult to get demo paddles.  In that case, probably the best way to compare speeds is to use Kaper drag data if you can get it.  CLC does not publish this data but it was included in all the reviews done by the old Sea Kayaker Magazine.  Luckily, I bought copies of their reviews for both the Ch17 and S&G Petrel Play before they went under.  Some designers, like Nick Schade, Bjorn Thomassen and Dan Cauette (Clearstream Custom Watercraft) provide drag data on their designs.

If you can’t demo the boats and can’t get the drag data, you are left with using speed data reported by other paddlers.  Paddler power is half of the speed equation, so it is important to understand what kind of a “motor” was used to generate the speed data.  A skilled, fit, thin, young paddler may report speeds in his Wood Duck that are greater than a portly mature paddler’s speed in a Pax 18, although the latter boat is undoubtably faster.  For me, the greatest value in this kind of data is to create speed differentials between boats.  If a paddler reports that he is 0.2 MPH faster in boat A than boat B, it is likely that I will see similar results.

One last item to discuss is the use of GPS for speed measurement.  I suspect that most of the numbers reported above are from GPS receivers.  The bottom line is that GPS computed speeds for short sprint distances (<30-60 seconds) are meaningless.  For this reason, I will not be providing “sprint” speeds.  More info provided below.

With all of that out of the way, here is the data for our kayaks, including two commercial boats.  My motor is 58 years old, 5’7”tall and weighs 152#.  I would probably be classified as an advanced paddler and am in excellent aerobic condition.  Race pace data is 8-12 miles, heart rate ~152 and an 80 SPM cadence with Epic Small Mid-Wing paddle.  All day pace is heart rate ~125 with a 70 SPM cadence and smaller Jantex Rio Small Plus Wing paddle.  Data was recorded with Garmin Fenix 5x and downloaded to Garmin Connect:

S&G Petrel Play (14’ x 23”) – Race 5.2 mph (11:30 min/mile) – All Day ~4.8 mph (12:30 min/mile)

90% BTD Frej (15’ x 19”) – This is my wife’s boat, so I paddle it very little.  I have one 5-mile paddle averaging 5.4 mph (11:05 mile/min).  This boat is very tight for me so I can’t get my legs into the stroke and get very little rotation.  I would call the pace midway between race and all day.  This is a very sleek boat and is quite fast for its length.  With a higher deck, I don’t doubt that I could paddle it faster than either the 16LT or 17LT.

Ch16LT (15’6” x 23”) – Race 5.4 mph (11:06 min/mile).  All Day 5.2mph (11:30mile/min).

Ch17LT (16’10” x 23”) – Race 5.5 mph (11:00 min/mile).  All Day 5.2 mph (11:30 mile/min). 

Shearwater Double (18.5’ x 27”) – I don’t have a lot of precise speed info because nearly all its use is recreational and leisurely.  My flea-weight (5’2”, 115#) wife and I did one 10k recreational race and averaged 5.7 mph (10:30 min/mile) in horrible conditions (30 kt headwind for the first half).  We could have shaved several minutes off our time, but we throttled way back at the half-way point.  We were far ahead of the nearest boat and I had paddled a 20k race the day before, so we took it easy.  During relaxed paddling, my wife and I paddle in the low 5’s and when she stops paddling, I move the boat in the upper 4s.  I have paddled it with a guy friend who is a decent paddler and we could maintain 6 mph but not much faster.     

Wahoo FSK (18.5’ x 20.5”) – Race 6 mph (9:55 min/mile).  All Day 5.7 mph (10:30 mile/min).  Note that race pace is with raised Nelo rotating seat which helps with rotation.  All day pace is with a comfortable foam seat.  I have paddled this boat in many races, and find it competitive with the Epic 18x, V8 and Stellar 18R.  It is a bit slower than the Epic V8 Pro.  This was my first race boat and I have over 1200 miles in it.

Mystery (20’ x 20”) – Race 6.2 mph (9:40 min/mile).  All Day 5.8 mph (10:20 min/mile).   Note that race pace is with a raised Nelo rotating seat which helps with rotation.  All day pace is with a comfortable foam seat.  I have paddled this boat in three races, and find it faster than the Epic 18x, V8 and Stellar 18R, and competitive with the V10 Sport.  It is slower than the Epic V10 and Stellar SEI.  I have 170 miles in this boat and plan to race it in the Chattajack 31 in ten days.

Stellar SEI Surfski (20’ x 18.1”) – Race 6.3 mph (9:30 min/mile).  Personal best on my standard eight-mile training course is 6.4 mph (10:24 min/mile).  All Day is probably 6.0 mph (10 min/mile) but the hard surfski bucket is hard to sit in over three hours.  This is my currently my preferred race boat, and I have numerous races and over 850 miles in it.  It has shown itself competitive with the Epic V10, but slower than a well paddled elite surfski.  You can tell when an elite ski is not well paddled, because the paddler will be swimming next to it.  Those are easy to pass.   

Stellar Rapid-S (20’3” x 16.3”) – This is the boat that I bought without a demo paddle and have always regretted it.  At Race pace, I can paddle this boat 6.5 mph (9:15 min/mile) but only for 2-3 miles when using the standard ICF K1 style hard seat.  After that, my legs fall asleep and my speed drops significantly.  I replaced the hard seat with a foam seat which greatly improved comfort but restricts rotation a bit.  With the foam seat, I can paddle 10-12 miles in relative comfort, but my speed is basically the same as the SEI above.  This is not a boat that I will paddle more than a couple of hours.  Due to the stability of this boat, I am unable to generate as much power as I can in the other boats.  I also must be very careful where I paddle it because wave/wakes are very perilous, and it is impossible to wet re-board this boat.  I have paddled the Rapid-S 375 miles but hope to replace it with either a Stellar SES or SEA soon.  Both of those boats are traditional skis which can easily be re-boarded in deep water. 

GPS SPEED DISCUSSION

A bit of a warning here, GPS is a subject where I have significant technical knowledge as a result of my work. IMHO, the number one error of consumer level GPS users is to overestimate the speed accuracy of GPS.  GPS calculates speed by determining the distance travelled between fixes and dividing by time. At surski speeds (~7 mph), you cover approximately 10 feet per second, so to get a good 2 sec speed reading, the unit must be able to measure 20' distances accurately. The problem is, GPS is not nearly that accurate. According to the owner of the GPS system (US Government), consumer grade non-augmented GPS receivers have an accuracy of about +/- 16' (the spec accuracy is generally 30'). This means that when a GPS tries to give you a two second speed reading, it will measure the distance as 20' +/- 16', which results in a speed reading of 7 +/- 5.5 mph. GPS manufacturers recognize this limitation so virtually all add speed smoothing algorithms to their processors so that the user does not see that much scatter.  These algorithms do a good job when operating at a steady speed but can produce some wild results with rapid speed or course changes. 

I have lots of observations to back up the theory.  Over the last twelve years, I have recorded and downloaded nearly every one of my workouts (run, paddle, bike, row, hike).  When I go back and review the downloads, I find that approximately 20% show a “maximum speed” that is physically impossible for me.  Another 40% of the events show maximum speeds that although physically possible, certainly exceed my effort that day.  Regardless of what my GPS says, I can’t run as fast as Usain Bolt.     

Very high end (Aviation and Professional Marine) GPS units are much better WRT speed for two reasons.  First, they all employ augmentation (WAAS here in North America) which improves the average accuracy down to <1 meter.  Secondly, they operate at a higher frequency.  Most consumer level GPS receivers operate at 1 Hz, where high end units operate at 5 or 10 Hz.  The operating frequency of a GPS receiver is more like the clock speed of a computer.  A 1 Hz GPS calculates position once per second where a 10 Hz unit does it 10 times per second.  (Do not confuse this with the refresh rate of the display.)  So, if we redo the geeky math above for 7 mph with a high-end GPS, a two second distance measurement would be 20 +/- 6’ which equates to 7 +/- 2 mph.

So, what do GPS manufacturers say about the speed accuracy of their units?  The answer is very little.  Reviewing the owner’s manuals of the twelve GPS devices that I currently have, only two make any mention of the accuracy of their displayed speed.  One is an older (non-augmented) driving GPS and it says that its speed should be “within one MPH at highway speeds.”  The other is a newer augmented (WAAS) hiking GPS with a twelve-satellite receiver, which lists its speed accuracy as 0.22 MPH steady state.  The implication of the latter spec is that the speed accuracy would be (much) lower in a dynamic environment involving acceleration/deceleration/turns. 

The bottom line from this discussion is that the speed calculated by your GPS has little meaning in dynamic environments like surfing down a wave, sailing in a puff of wind or during turns.  Once stabilized for 30+ seconds on a constant course at a constant speed, the speed displayed should stabilize and be reasonably accurate.  This assumes of course, that the GPS is placed in a position that it has a good unobstructed hemispherical view of the sky.  GPS signals are weak when they reach the earth from the satellite orbiting at 12550 miles, so it does not take much of an obstruction to block the signals from some satellites and significantly degrade your GPS accuracy.     

Good post Mark, thank you. My Garmin ETrex seemed notoriously inaccurate when I used it in the boats - on the Google Earth trace I posted some time ago it showed a maximum elevation of 8 metres and a couple of other peaks around 5 metres. The track was recorded on a windless day with a pretty much flat sea. Five and 8 metre peaks? I'm not that brave! 

Yambo,

It's just as bad when you're on land, but you aren't as aware of sea level and so the error isn't as obvious.

The US FAA has measured actual vertical accuracy in GPS to be 4.7 meters, which is right in line with your errors. If you had access to WAAS, which only works in the Western Hemisphere, it would be 1.3 meters.

There are also errors caused by the difference between the actual shape of the Earth and the mathematical model of the shape used in the calculations. The WGS84 model currently the most used in civilian receivers is supposed to accurate overall to +/- 1 m.

Measurements taken on the water are also affected by how seal level is defined in the mapping application. It's almost guaranteed to never match up with the actual water level due to tidal variation.

So your vertical errors are pretty reasonable for how the system works and not the fault of your receiver.

Laszlo

An addendum about the Wood Duck 12 sprint speed in light of Mark's excellent discussion of GPS inaccuracies.

I did indeed get that value using the max speed function of my GPS unit. However, it was a 50-satellite receiver tracking 18 satellites at the time, WAAS was enabled and the correction had been applied to all the satellites and it was a 5Hz unit (though the display and NMEA string output were 1 Hz).

There was no wind, it was low slack tide, the course was a straight line orthogonal to the direction of tidal flow. There was an unobstructed view of the entire sky from the water and the run was on the order of a minute. Just before I started, I observed the receiver to verify that it was stable (no sudden changes in position or velocity) and I reset the trip computer function to clear all previous data.

I was seriously trying to get an accurate reading and, like Mark, I've had some experience with GPS and its vagaries. That's why all the elaborate setup and noting of the conditions. So, while I can't give an exact statement of error for the reading, I'm pretty confident that it's in the right ballpark.

Laszlo

 Thanks Laszlo. the GPS is no longer with us and isn't really missed. I'm very much a map/chart and compass guy although not a complete Luddite - I use Navionics quite a lot in my fishing boat.  

   I totally agree that "maxium speed" as measured by a phone GPS is worthless. But I do think that a sprint speed measured over at least 30 seconds -- (preferably more but who can "sprint" for much longer?) -- is worth measuring. I've found it to be fairly consistent in my own testing and I'm glad that Mark agrees: "Once stabilized for 30+ seconds on a constant course at a constant speed, the speed displayed should stabilize and be reasonably accurate."

As an avid cyclist, the most distressing part of such measurement errors is the great uncertainty about elevation gain data.  Strava basically gives up on this and defaults to elevation data from maps unless the cyclist is using a barometric altimeter. I'd appreciate further insight on this, but I should think that the margin of error for tiny barometric altimeters is quite substantial, leading to very suspect data in recording the short hill climbs of most cycling routes. . . . I realize this it way out of bounds for a forum on boats. But I doubt I'm the only peddler/paddler on the Forum.

 As an alternative, I'll be spending my winter months trying to wire a Garmin paddle-wheel sensor and some accelerometers to an arduino board. In theory this should resolve speed fluctuations at sub-second intervals. In practice... we'll see!

If you get that done, please do report back. There are some interesting challenges with that approach and it will be fun to see how you solve them.

Laszlo

Compass and GPS might be right up there with the dressing table mirror and the bathroom scale in terms of being devices which make no concession to human vanity.  <;-)

.....Michael